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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text @@ -0,0 +1,3079 @@ +The Project Gutenberg EBook of The Atomic Bombings of Hiroshima and +Nagasaki, by United States + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: The Atomic Bombings of Hiroshima and Nagasaki + +Author: United States + +Posting Date: August 3, 2008 [EBook #685] +Release Date: October, 1996 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK ATOMIC BOMBINGS, HIROSHIMA, NAGASAKI *** + + + + +Produced by Gregory Walker + + + + + + + + + + For an HTML version of this document and additional + public domain documents on nuclear history, visit + Trinity Atomic Web Site: + http://www.envirolink.org/issues/nuketesting/ + + + + + +THE ATOMIC BOMBINGS OF HIROSHIMA AND NAGASAKI + +by The Manhattan Engineer District, June 29, 1946. + + + +Index + + + FOREWORD + INTRODUCTION + THE MANHATTAN PROJECT INVESTIGATING GROUP + PROPAGANDA + SUMMARY OF DAMAGES AND INJURIES + MAIN CONCLUSIONS + THE SELECTION OF THE TARGET + DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS + Hiroshima + Nagasaki + THE ATTACKS + Hiroshima + Nagasaki + GENERAL COMPARISON OF HIROSHIMA AND NAGASAKI + GENERAL DESCRIPTION OF DAMAGE CAUSED BY THE ATOMIC EXPLOSIONS + TOTAL CASUALTIES + THE NATURE OF AN ATOMIC EXPLOSION + CHARACTERISTICS OF THE DAMAGE CAUSED BY THE ATOMIC BOMBS + CALCULATIONS OF THE PEAK PRESSURE OF THE BLAST WAVE + LONG RANGE BLAST DAMAGE + GROUND SHOCK + SHIELDING, OR SCREENING, FROM THE BLAST + FLASH BURN + CHARACTERISTICS OF INJURIES TO PERSONS + BURNS + MECHANICAL INJURIES + BLAST INJURIES + RADIATION INJURIES + SHIELDING FROM RADIATION + EFFECTS OF THE ATOMIC BOMBINGS ON THE INHABITANTS OF THE CITIES + APPENDIX: Father Siemes' eyewitness account + + + +FOREWORD + +This report describes the effects of the atomic bombs which were +dropped on the Japanese cities of Hiroshima and Nagasaki on August 6 +and 9, 1945, respectively. It summarizes all the authentic information +that is available on damage to structures, injuries to personnel, +morale effect, etc., which can be released at this time without +prejudicing the security of the United States. + +This report has been compiled by the Manhattan Engineer District of the +United States Army under the direction of Major General Leslie R. +Groves. Special acknowledgement to those whose work contributed +largely to this report is made to: + + The Special Manhattan Engineer District Investigating Group, + The United States Strategic Bombing Survey, + The British Mission to Japan, and + +The Joint Atomic Bomb Investigating Group (Medical). and particularly +to the following individuals: + +Col. Stafford L. Warren, Medical Corps, United States Army, for his +evaluation of medical data, + +Capt. Henry L. Barnett, Medical Corps, United States Army, for his +evaluation of medical data, + +Dr. R. Serber, for his comments on flash burn, + +Dr. Hans Bethe, Cornell University, for his information of the nature +of atomic explosions, + +Majors Noland Varley and Walter C. Youngs, Corps of Engineers, United +States Army, for their evaluation of physical damage to structures, + +J. 0. Hirschfelder, J. L. Magee, M. Hull, and S. T. Cohen, of the Los +Alamos Laboratory, for their data on nuclear explosions, + +Lieut. Col. David B. Parker, Corps of Engineers, United States Army, +for editing this report. + + + +INTRODUCTION + +Statement by the President of the United States: "Sixteen hours ago an +American airplane dropped one bomb on Hiroshima, Japan, and destroyed +its usefulness to the enemy. That bomb had more power than 20,000 tons +of T.N.T. It had more than two thousand times the blast power of the +British Grand Slam, which is the largest bomb ever yet used in the +history of warfare". + +These fateful words of the President on August 6th, 1945, marked the +first public announcement of the greatest scientific achievement in +history. The atomic bomb, first tested in New Mexico on July 16, 1945, +had just been used against a military target. + +On August 6th, 1945, at 8:15 A.M., Japanese time, a B-29 heavy bomber +flying at high altitude dropped the first atomic bomb on Hiroshima. +More than 4 square miles of the city were instantly and completely +devastated. 66,000 people were killed, and 69,000 injured. + +On August 9th, three days later, at 11:02 A.M., another B-29 dropped +the second bomb on the industrial section of the city of Nagasaki, +totally destroying 1 1/2 square miles of the city, killing 39,000 +persons, and injuring 25,000 more. + +On August 10, the day after the atomic bombing of Nagasaki, the +Japanese government requested that it be permitted to surrender under +the terms of the Potsdam declaration of July 26th which it had +previously ignored. + + + +THE MANHATTAN PROJECT ATOMIC BOMB INVESTIGATING GROUP + +On August 11th, 1945, two days after the bombing of Nagasaki, a message +was dispatched from Major General Leslie R. Groves to Brigadier General +Thomas F. Farrell, who was his deputy in atomic bomb work and was +representing him in operations in the Pacific, directing him to +organize a special Manhattan Project Atomic Bomb Investigating Group. + +This Group was to secure scientific, technical and medical intelligence +in the atomic bomb field from within Japan as soon as possible after +the cessation of hostilities. The mission was to consist of three +groups: + + 1. Group for Hiroshima. + 2. Group for Nagasaki. + 3. Group to secure information concerning general Japanese activities in + the field of atomic bombs. + +The first two groups were organized to accompany the first American +troops into Hiroshima and Nagasaki. + +The primary purposes of the mission were as follows, in order of +importance: + +1. To make certain that no unusual hazards were present in the bombed +cities. + +2. To secure all possible information concerning the effects of the +bombs, both usual and unusual, and particularly with regard to +radioactive effects, if any, on the targets or elsewhere. + +General Groves further stated that all available specialist personnel +and instruments would be sent from the United States, and that the +Supreme Allied Commander in the Pacific would be informed about the +organization of the mission. + +On the same day, 11 August, the special personnel who formed the part +of the investigating group to be sent from the United States were +selected and ordered to California with instructions to proceed +overseas at once to accomplish the purposes set forth in the message to +General Farrell. The main party departed from Hamilton Field, +California on the morning of 13 August and arrived in the Marianas on +15 August. + +On 12 August the Chief of Staff sent the Theater Commander the +following message: + +"FOR MACARTHUR, SIGNED MARSHALL: + +"GROVES HAS ORDERED FARRELL AT TINIAN TO ORGANIZE A SCIENTIFIC GROUP OF +THREE SECTIONS FOR POTENTIAL USE IN JAPAN IF SUCH USE SHOULD BE +DESIRED. THE FIRST GROUP IS FOR HIROSHIMA, THE SECOND FOR NAGASAKI, +AND THE THIRD FOR THE PURPOSE OF SECURING INFORMATION CONCERNING +GENERAL JAPANESE ACTIVITIES IN THE FIELD OF ATOMIC WEAPONS. THE GROUPS +FOR HIROSHIMA AND NAGASAKI SHOULD ENTER THOSE CITIES WITH THE FIRST +AMERICAN TROOPS IN ORDER THAT THESE TROOPS SHALL NOT BE SUBJECTED TO +ANY POSSIBLE TOXIC EFFECTS ALTHOUGH WE HAVE NO REASON TO BELIEVE THAT +ANY SUCH EFFECTS ACTUALLY EXIST. FARRELL AND HIS ORGANIZATION HAVE ALL +AVAILABLE INFORMATION ON THIS SUBJECT." + +General Farrell arrived in Yokohama on 30 August, with the Commanding +General of the 8th Army; Colonel Warren, who was Chief of the +Radiological Division of the District, arrived on 7 September. The +main body of the investigating group followed later. Preliminary +inspections of Hiroshima and Nagasaki were made on 8-9 and 13-14 +September, respectively. Members of the press had been enabled to +precede General Farrell to Hiroshima. + +The special groups spent 16 days in Nagasaki and 4 days in Hiroshima, +during which time they collected as much information as was possible +under their directives which called for a prompt report. After General +Farrell returned to the U.S. to make his preliminary report, the groups +were headed by Brigadier General J. B. Newman, Jr. More extensive +surveys have been made since that time by other agencies who had more +time and personnel available for the purpose, and much of their +additional data has thrown further light on the effects of the +bombings. This data has been duly considered in the making of this +report. + + + +PROPAGANDA + +On the day after the Hiroshima strike, General Farrell received +instructions from the War Department to engage in a propaganda campaign +against the Japanese Empire in connection with the new weapon and its +use against Hiroshima. The campaign was to include leaflets and any +other propaganda considered appropriate. With the fullest cooperation +from CINCPAC of the Navy and the United States Strategic Air Forces, he +initiated promptly a campaign which included the preparation and +distribution of leaflets, broadcasting via short wave every 15 minutes +over radio Saipan and the printing at Saipan and distribution over the +Empire of a Japanese language newspaper which included the description +and photographs of the Hiroshima strike. + +The campaign proposed: + +1. Dropping 16,000,000 leaflets in a period of 9 days on 47 Japanese +cities with population of over 100,000. These cities represented more +than 40% of the total population. + +2. Broadcast of propaganda at regular intervals over radio Saipan. + +3. Distribution of 500,000 Japanese language newspapers containing +stories and pictures of the atomic bomb attacks. + +The campaign continued until the Japanese began their surrender +negotiations. At that time some 6,000,000 leaflets and a large number +of newspapers had been dropped. The radio broadcasts in Japanese had +been carried out at regular 15 minute intervals. + + + +SUMMARY OF DAMAGES AND INJURIES + +Both the Hiroshima and the Nagasaki atomic bombs exhibited similar +effects. + +The damages to man-made structures and other inanimate objects was the +result in both cities of the following effects of the explosions: + +A. Blast, or pressure wave, similar to that of normal explosions. + +B. Primary fires, i.e., those fires started instantaneously by the +heat radiated from the atomic explosion. + +C. Secondary fires, i.e., those fires resulting from the collapse of +buildings, damage to electrical systems, overturning of stoves, and +other primary effects of the blast. + +D. Spread of the original fires (B and C) to other structures. + +The casualties sustained by the inhabitants of both cities were due to: + +A. "Flash" burns, caused directly by the almost instantaneous +radiation of heat and light at the moment of the explosion. + +B. Burns resulting from the fires caused by the explosion. + +C. Mechanical injuries caused by collapse of buildings, flying debris, +and forceable hurling--about of persons struck by the blast pressure +waves. + +D. Radiation injuries caused by the instantaneous penetrating +radiation (in many respects similar to excessive X-ray exposure) from +the nuclear explosion; all of these effective radiations occurred +during the first minute after initiation of the explosion, and nearly +all occurred during the first second of the explosion. + +No casualties were suffered as a result of any persistent radioactivity +of fission products of the bomb, or any induced radioactivity of +objects near the explosion. The gamma radiations emitted by the +nuclear explosion did not, of course, inflict any damage on structures. + +The number of casualties which resulted from the pure blast effect +alone (i.e., because of simple pressure) was probably negligible in +comparison to that caused by other effects. + +The central portions of the cities underneath the explosions suffered +almost complete destruction. The only surviving objects were the +frames of a small number of strong reinforced concrete buildings which +were not collapsed by the blast; most of these buildings suffered +extensive damage from interior fires, had their windows, doors, and +partitions knocked out, and all other fixtures which were not integral +parts of the reinforced concrete frames burned or blown away; the +casualties in such buildings near the center of explosion were almost +100%. In Hiroshima fires sprang up simultaneously all over the wide +flat central area of the city; these fires soon combined in an immense +"fire storm" (high winds blowing inwards toward the center of a large +conflagration) similar to those caused by ordinary mass incendiary +raids; the resulting terrific conflagration burned out almost +everything which had not already been destroyed by the blast in a +roughly circular area of 4.4 square miles around the point directly +under the explosion (this point will hereafter in this report be +referred to as X). Similar fires broke out in Nagasaki, but no +devastating fire storm resulted as in Hiroshima because of the +irregular shape of the city. + +In both cities the blast totally destroyed everything within a radius +of 1 mile from the center of explosion, except for certain reinforced +concrete frames as noted above. The atomic explosion almost completely +destroyed Hiroshima's identity as a city. Over a fourth of the +population was killed in one stroke and an additional fourth seriously +injured, so that even if there had been no damage to structures and +installations the normal city life would still have been completely +shattered. Nearly everything was heavily damaged up to a radius of 3 +miles from the blast, and beyond this distance damage, although +comparatively light, extended for several more miles. Glass was broken +up to 12 miles. + +In Nagasaki, a smaller area of the city was actually destroyed than in +Hiroshima, because the hills which enclosed the target area restricted +the spread of the great blast; but careful examination of the effects +of the explosion gave evidence of even greater blast effects than in +Hiroshima. Total destruction spread over an area of about 3 square +miles. Over a third of the 50,000 buildings in the target area of +Nagasaki were destroyed or seriously damaged. The complete destruction +of the huge steel works and the torpedo plant was especially +impressive. The steel frames of all buildings within a mile of the +explosion were pushed away, as by a giant hand, from the point of +detonation. The badly burned area extended for 3 miles in length. The +hillsides up to a radius of 8,000 feet were scorched, giving them an +autumnal appearance. + + + +MAIN CONCLUSIONS + +The following are the main conclusions which were reached after +thorough examination of the effects of the bombs dropped on Hiroshima +and Nagasaki: + +1. No harmful amounts of persistent radioactivity were present after +the explosions as determined by: + +A. Measurements of the intensity of radioactivity at the time of the +investigation; and + +B. Failure to find any clinical evidence of persons harmed by +persistent radioactivity. + +The effects of the atomic bombs on human beings were of three main +types: + +A. Burns, remarkable for (1) the great ground area over which they +were inflicted and (2) the prevalence of "flash" burns caused by the +instantaneous heat radiation. + +B. Mechanical injuries, also remarkable for the wide area in which +suffered. + +C. Effects resulting from penetrating gamma radiation. The effects +from radiation were due to instantaneous discharge of radiation at the +moment of explosion and not to persistent radioactivity (of either +fission products or other substances whose radioactivity might have +been induced by proximity to the explosions). + +The effects of the atomic bombs on structures and installations were of +two types: + +A. Destruction caused by the great pressure from the blast; and + +B. Destruction caused by the fires, either started directly by the +great heat radiation, or indirectly through the collapse of buildings, +wiring, etc. + +4. The actual tonnage of T.N.T. which would have caused the same blast +damage was approximately of the order of 20,000 tons. + +5. In respect to their height of burst, the bombs performed exactly +according to design. + +6. The bombs were placed in such positions that they could not have +done more damage from any alternative bursting point in either city. + +7. The heights of burst were correctly chosen having regard to the +type of destruction it was desired to cause. + +8. The information collected would enable a reasonably accurate +prediction to be made of the blast damage likely to be caused in any +city where an atomic explosion could be effected. + + + +THE SELECTION OF THE TARGET + +Some of the most frequent queries concerning the atomic bombs are those +dealing with the selection of the targets and the decision as to when +the bombs would be used. + +The approximate date for the first use of the bomb was set in the fall +of 1942 after the Army had taken over the direction of and +responsibility for the atomic bomb project. At that time, under the +scientific assumptions which turned out to be correct, the summer of +1945 was named as the most likely date when sufficient production would +have been achieved to make it possible actually to construct and +utilize an atomic bomb. It was essential before this time to develop +the technique of constructing and detonating the bomb and to make an +almost infinite number of scientific and engineering developments and +tests. Between the fall of 1942 and June 1945, the estimated +probabilities of success had risen from about 60% to above 90%; +however, not until July 16, 1945, when the first full-scale test took +place in New Mexico, was it conclusively proven that the theories, +calculations, and engineering were correct and that the bomb would be +successful. + + +The test in New Mexico was held 6 days after sufficient material had +become available for the first bomb. The Hiroshima bomb was ready +awaiting suitable weather on July 31st, and the Nagasaki bomb was used +as soon after the Hiroshima bomb as it was practicable to operate the +second mission. + +The work on the actual selection of targets for the atomic bomb was +begun in the spring of 1945. This was done in close cooperation with +the Commanding General, Army Air Forces, and his Headquarters. A +number of experts in various fields assisted in the study. These +included mathematicians, theoretical physicists, experts on the blast +effects of bombs, weather consultants, and various other specialists. +Some of the important considerations were: + +A. The range of the aircraft which would carry the bomb. + +B. The desirability of visual bombing in order to insure the most +effective use of the bomb. + +C. Probable weather conditions in the target areas. + +D. Importance of having one primary and two secondary targets for each +mission, so that if weather conditions prohibited bombing the target +there would be at least two alternates. + +E. Selection of targets to produce the greatest military effect on the +Japanese people and thereby most effectively shorten the war. + +F. The morale effect upon the enemy. + +These led in turn to the following: + +A. Since the atomic bomb was expected to produce its greatest amount +of damage by primary blast effect, and next greatest by fires, the +targets should contain a large percentage of closely-built frame +buildings and other construction that would be most susceptible to +damage by blast and fire. + +B. The maximum blast effect of the bomb was calculated to extend over +an area of approximately 1 mile in radius; therefore the selected +targets should contain a densely built-up area of at least this size. + +C. The selected targets should have a high military strategic value. + +D. The first target should be relatively untouched by previous +bombing, in order that the effect of a single atomic bomb could be +determined. + +The weather records showed that for five years there had never been two +successive good visual bombing days over Tokyo, indicating what might +be expected over other targets in the home islands. The worst month of +the year for visual bombing was believed to be June, after which the +weather should improve slightly during July and August and then become +worse again during September. Since good bombing conditions would +occur rarely, the most intense plans and preparations were necessary in +order to secure accurate weather forecasts and to arrange for full +utilization of whatever good weather might occur. It was also very +desirable to start the raids before September. + + + +DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS + +Hiroshima + +The city of Hiroshima is located on the broad, flat delta of the Ota +River, which has 7 channel outlets dividing the city into six islands +which project into Hiroshima Bay. The city is almost entirely flat and +only slightly above sea level; to the northwest and northeast of the +city some hills rise to 700 feet. A single hill in the eastern part of +the city proper about 1/2 mile long and 221 feet in height interrupted +to some extent the spreading of the blast damage; otherwise the city +was fully exposed to the bomb. Of a city area of over 26 square miles, +only 7 square miles were completely built-up. There was no marked +separation of commercial, industrial, and residential zones. 75% of +the population was concentrated in the densely built-up area in the +center of the city. + +Hiroshima was a city of considerable military importance. It contained +the 2nd Army Headquarters, which commanded the defense of all of +southern Japan. The city was a communications center, a storage point, +and an assembly area for troops. To quote a Japanese report, "Probably +more than a thousand times since the beginning of the war did the +Hiroshima citizens see off with cries of 'Banzai' the troops leaving +from the harbor." + +The center of the city contained a number of reinforced concrete +buildings as well as lighter structures. Outside the center, the area +was congested by a dense collection of small wooden workshops set among +Japanese houses; a few larger industrial plants lay near the outskirts +of the city. The houses were of wooden construction with tile roofs. +Many of the industrial buildings also were of wood frame construction. +The city as a whole was highly susceptible to fire damage. + +Some of the reinforced concrete buildings were of a far stronger +construction than is required by normal standards in America, because +of the earthquake danger in Japan. This exceptionally strong +construction undoubtedly accounted for the fact that the framework of +some of the buildings which were fairly close to the center of damage +in the city did not collapse. + +The population of Hiroshima had reached a peak of over 380,000 earlier +in the war but prior to the atomic bombing the population had steadily +decreased because of a systematic evacuation ordered by the Japanese +government. At the time of the attack the population was approximately +255,000. This figure is based on the registered population, used by +the Japanese in computing ration quantities, and the estimates of +additional workers and troops who were brought into the city may not be +highly accurate. Hiroshima thus had approximately the same number of +people as the city of Providence, R.I., or Dallas, Tex. + + +Nagasaki + +Nagasaki lies at the head of a long bay which forms the best natural +harbor on the southern Japanese home island of Kyushu. The main +commercial and residential area of the city lies on a small plain near +the end of the bay. Two rivers divided by a mountain spur form the two +main valleys in which the city lies. This mountain spur and the +irregular lay-out of the city tremendously reduced the area of +destruction, so that at first glance Nagasaki appeared to have been +less devastated than Hiroshima. + +The heavily build-up area of the city is confined by the terrain to +less than 4 square miles out of a total of about 35 square miles in the +city as a whole. + +The city of Nagasaki had been one of the largest sea ports in southern +Japan and was of great war-time importance because of its many and +varied industries, including the production of ordnance, ships, +military equipment, and other war materials. The narrow long strip +attacked was of particular importance because of its industries. + +In contrast to many modern aspects of Nagasaki, the residences almost +without exception were of flimsy, typical Japanese construction, +consisting of wood or wood-frame buildings, with wood walls with or +without plaster, and tile roofs. Many of the smaller industries and +business establishments were also housed in wooden buildings or +flimsily built masonry buildings. Nagasaki had been permitted to grow +for many years without conforming to any definite city zoning plan and +therefore residences were constructed adjacent to factory buildings and +to each other almost as close as it was possible to build them +throughout the entire industrial valley. + + + +THE ATTACKS + +Hiroshima + +Hiroshima was the primary target of the first atomic bomb mission. The +mission went smoothly in every respect. The weather was good, and the +crew and equipment functioned perfectly. In every detail, the attack +was carried out exactly as planned, and the bomb performed exactly as +expected. + +The bomb exploded over Hiroshima at 8:15 on the morning of August 6, +1945. About an hour previously, the Japanese early warning radar net +had detected the approach of some American aircraft headed for the +southern part of Japan. The alert had been given and radio +broadcasting stopped in many cities, among them Hiroshima. The planes +approached the coast at a very high altitude. At nearly 8:00 A.M., the +radar operator in Hiroshima determined that the number of planes coming +in was very small--probably not more than three--and the air raid alert +was lifted. The normal radio broadcast warning was given to the people +that it might be advisable to go to shelter if B-29's were actually +sighted, but no raid was expected beyond some sort of reconnaissance. +At 8:15 A.M., the bomb exploded with a blinding flash in the sky, and a +great rush of air and a loud rumble of noise extended for many miles +around the city; the first blast was soon followed by the sounds of +falling buildings and of growing fires, and a great cloud of dust and +smoke began to cast a pall of darkness over the city. + +At 8:16 A.M., the Tokyo control operator of the Japanese Broadcasting +Corporation noticed that the Hiroshima station had gone off the air. +He tried to use another telephone line to reestablish his program, but +it too had failed. About twenty minutes later the Tokyo railroad +telegraph center realized that the main line telegraph had stopped +working just north of Hiroshima. From some small railway stops within +ten miles of the city there came unofficial and confused reports of a +terrible explosion in Hiroshima. All these reports were transmitted to +the Headquarters of the Japanese General Staff. + +Military headquarters repeatedly tried to call the Army Control Station +in Hiroshima. The complete silence from that city puzzled the men at +Headquarters; they knew that no large enemy raid could have occurred, +and they knew that no sizeable store of explosives was in Hiroshima at +that time. A young officer of the Japanese General Staff was +instructed to fly immediately to Hiroshima, to land, survey the damage, +and return to Tokyo with reliable information for the staff. It was +generally felt at Headquarters that nothing serious had taken place, +that it was all a terrible rumor starting from a few sparks of truth. + +The staff officer went to the airport and took off for the southwest. +After flying for about three hours, while still nearly 100 miles from +Hiroshima, he and his pilot saw a great cloud of smoke from the bomb. +In the bright afternoon, the remains of Hiroshima were burning. + +Their plane soon reached the city, around which they circled in +disbelief. A great scar on the land, still burning, and covered by a +heavy cloud of smoke, was all that was left of a great city. They +landed south of the city, and the staff officer immediately began to +organize relief measures, after reporting to Tokyo. + +Tokyo's first knowledge of what had really caused the disaster came +from the White House public announcement in Washington sixteen hours +after Hiroshima had been hit by the atomic bomb. + + +Nagasaki + +Nagasaki had never been subjected to large scale bombing prior to the +explosion of the atomic bomb there. On August 1st, 1945, however, a +number of high explosive bombs were dropped on the city. A few of +these bombs hit in the shipyards and dock areas in the southwest +portion of the city. Several of the bombs hit the Mitsubishi Steel and +Arms Works and six bombs landed at the Nagasaki Medical School and +Hospital, with three direct hits on buildings there. While the damage +from these few bombs were relatively small, it created considerable +concern in Nagasaki and a number of people, principally school +children, were evacuated to rural areas for safety, thus reducing the +population in the city at the time of the atomic attack. + +On the morning of August 9th, 1945, at about 7:50 A.M., Japanese time, +an air raid alert was sounded in Nagasaki, but the "All clear" signal +was given at 8:30. When only two B-29 superfortresses were sighted at +10:53 the Japanese apparently assumed that the planes were only on +reconnaissance and no further alarm was given. A few moments later, at +11:00 o'clock, the observation B-29 dropped instruments attached to +three parachutes and at 11:02 the other plane released the atomic bomb. + +The bomb exploded high over the industrial valley of Nagasaki, almost +midway between the Mitsubishi Steel and Arms Works, in the south, and +the Mitsubishi-Urakami Ordnance Works (Torpedo Works), in the north, +the two principal targets of the city. + +Despite its extreme importance, the first bombing mission on Hiroshima +had been almost routine. The second mission was not so uneventful. +Again the crew was specially trained and selected; but bad weather +introduced some momentous complications. These complications are best +described in the brief account of the mission's weaponeer, Comdr., now +Capt., F. L. Ashworth, U.S.N., who was in technical command of the +bomb and was charged with the responsibility of insuring that the bomb +was successfully dropped at the proper time and on the designated +target. His narrative runs as follows: + +"The night of our take-off was one of tropical rain squalls, and +flashes of lightning stabbed into the darkness with disconcerting +regularity. The weather forecast told us of storms all the way from +the Marianas to the Empire. Our rendezvous was to be off the southeast +coast of Kyushu, some 1500 miles away. There we were to join with our +two companion observation B-29's that took off a few minutes behind us. +Skillful piloting and expert navigation brought us to the rendezvous +without incident. + +"About five minutes after our arrival, we were joined by the first of +our B-29's. The second, however, failed to arrive, having apparently +been thrown off its course by storms during the night. We waited 30 +minutes and then proceeded without the second plane toward the target +area. + +"During the approach to the target the special instruments installed in +the plane told us that the bomb was ready to function. We were +prepared to drop the second atomic bomb on Japan. But fate was against +us, for the target was completely obscured by smoke and haze. Three +times we attempted bombing runs, but without success. Then with +anti-aircraft fire bursting around us and with a number of enemy +fighters coming up after us, we headed for our secondary target, +Nagasaki. + +"The bomb burst with a blinding flash and a huge column of black smoke +swirled up toward us. Out of this column of smoke there boiled a great +swirling mushroom of gray smoke, luminous with red, flashing flame, +that reached to 40,000 feet in less than 8 minutes. Below through the +clouds we could see the pall of black smoke ringed with fire that +covered what had been the industrial area of Nagasaki. + +"By this time our fuel supply was dangerously low, so after one quick +circle of Nagasaki, we headed direct for Okinawa for an emergency +landing and refueling". + + + +GENERAL COMPARISON OF HIROSHIMA AND NAGASAKI + +It was not at first apparent to even trained observers visiting the two +Japanese cities which of the two bombs had been the most effective. + +In some respects, Hiroshima looked worse than Nagasaki. The fire +damage in Hiroshima was much more complete; the center of the city was +hit and everything but the reinforced concrete buildings had virtually +disappeared. A desert of clear-swept, charred remains, with only a few +strong building frames left standing was a terrifying sight. + +At Nagasaki there were no buildings just underneath the center of +explosion. The damage to the Mitsubishi Arms Works and the Torpedo +Works was spectacular, but not overwhelming. There was something left +to see, and the main contours of some of the buildings were still +normal. + +An observer could stand in the center of Hiroshima and get a view of +the most of the city; the hills prevented a similar overall view in +Nagasaki. Hiroshima impressed itself on one's mind as a vast expanse +of desolation; but nothing as vivid was left in one's memory of +Nagasaki. + +When the observers began to note details, however, striking differences +appeared. Trees were down in both cities, but the large trees which +fell in Hiroshima were uprooted, while those in Nagasaki were actually +snapped off. A few reinforced concrete buildings were smashed at the +center in Hiroshima, but in Nagasaki equally heavy damage could be +found 2,300 feet from X. In the study of objects which gave definite +clues to the blast pressure, such as squashed tin cans, dished metal +plates, bent or snapped poles and like, it was soon evident that the +Nagasaki bomb had been much more effective than the Hiroshima bomb. In +the description of damage which follows, it will be noted that the +radius for the amount of damage was greater in Nagasaki than Hiroshima. + + + +GENERAL DESCRIPTION OF DAMAGE CAUSED BY THE ATOMIC EXPLOSIONS + +In considering the devastation in the two cities, it should be +remembered that the cities' differences in shape and topography +resulted in great differences in the damages. Hiroshima was all on +low, flat ground, and was roughly circular in shape; Nagasaki was much +cut up by hills and mountain spurs, with no regularity to its shape. + +In Hiroshima almost everything up to about one mile from X was +completely destroyed, except for a small number (about 50) of heavily +reinforced concrete buildings, most of which were specially designed to +withstand earthquake shock, which were not collapsed by the blast; most +of these buildings had their interiors completely gutted, and all +windows, doors, sashes, and frames ripped out. In Nagasaki, nearly +everything within 1/2 mile of the explosion was destroyed, including +heavy structures. All Japanese homes were destroyed within 1 1/2 miles +from X. + +Underground air raid shelters with earth cover roofs immediately below +the explosion had their roofs caved in; but beyond 1/2 mile from X they +suffered no damage. + +In Nagasaki, 1500 feet from X high quality steel frame buildings were +not completely collapsed, but the entire buildings suffered mass +distortion and all panels and roofs were blown in. + +In Nagasaki, 2,000 feet from X, reinforced concrete buildings with 10" +walls and 6" floors were collapsed; reinforced concrete buildings with +4" walls and roofs were standing but were badly damaged. At 2,000 feet +some 9" concrete walls were completely destroyed. + +In Nagasaki, 3,500 feet from X, church buildings with 18" brick walls +were completely destroyed. 12" brick walls were severely cracked as +far as 5,000 feet. + +In Hiroshima, 4,400 feet from X, multi-story brick buildings were +completely demolished. In Nagasaki, similar buildings were destroyed +to 5,300 feet. + +In Hiroshima, roof tiles were bubbled (melted) by the flash heat out to +4,000 feet from X; in Nagasaki, the same effect was observed to 6,500 +feet. + +In Hiroshima, steel frame buildings were destroyed 4,200 feet from X, +and to 4,800 feet in Nagasaki. + +In both cities, the mass distortion of large steel buildings was +observed out to 4,500 feet from X. + +In Nagasaki, reinforced concrete smoke stacks with 8" walls, specially +designed to withstand earthquake shocks, were overturned up to 4,000 +feet from X. + +In Hiroshima, steel frame buildings suffered severe structural damage +up to 5,700 feet from X, and in Nagasaki the same damage was sustained +as far as 6,000 feet. + +In Nagasaki, 9" brick walls were heavily cracked to 5,000 feet, were +moderately cracked to 6,000 feet, and slightly cracked to 8,000 feet. +In both cities, light concrete buildings collapsed out to 4,700 feet. + +In Hiroshima, multi-story brick buildings suffered structural damage up +to 6,600 feet, and in Nagasaki up to 6,500 feet from X. + +In both cities overhead electric installations were destroyed up to +5,500 feet; and trolley cars were destroyed up to 5,500 feet, and +damaged to 10,500 feet. + +Flash ignition of dry, combustible material was observed as far as +6,400 feet from X in Hiroshima, and in Nagasaki as far as 10,000 feet +from X. + +Severe damage to gas holders occured out to 6,500 feet in both cities. + +All Japanese homes were seriously damaged up to 6,500 feet in +Hiroshima, and to 8,000 feet in Nagasaki. Most Japanese homes were +damaged up to 8,000 feet in Hiroshima and 10,500 feet in Nagasaki. + +The hillsides in Nagasaki were scorched by the flash radiation of heat +as far as 8,000 feet from X; this scorching gave the hillsides the +appearance of premature autumn. + +In Nagasaki, very heavy plaster damage was observed in many buildings +up to 9,000 feet; moderate damage was sustained as far as 12,000 feet, +and light damage up to 15,000 feet. + +The flash charring of wooden telegraph poles was observed up to 9,500 +feet from X in Hiroshima, and to 11,000 feet in Nagasaki; some reports +indicate flash burns as far as 13,000 feet from X in both places. + +Severe displacement of roof tiles was observed up to 8,000 feet in +Hiroshima, and to 10,000 feet in Nagasaki. + +In Nagasaki, very heavy damage to window frames and doors was observed +up to 8,000 feet, and light damage up to 12,000 feet. + +Roofs and wall coverings on steel frame buildings were destroyed out to +11,000 feet. + +Although the sources of many fires were difficult to trace accurately, +it is believed that fires were started by primary heat radiation as far +as 15,000 feet from X. + +Roof damage extended as far as 16,000 feet from X in Hiroshima and in +Nagasaki. + +The actual collapse of buildings was observed at the extreme range of +23,000 feet from X in Nagasaki. + +Although complete window damage was observed only up to 12,000 feet +from X, some window damage occurred in Nagasaki up to 40,000 feet, and +actual breakage of glass occured up to 60,000 feet. + +Heavy fire damage was sustained in a circular area in Hiroshima with a +mean radius of about 6,000 feet and a maximum radius of about 11,000 +feet; similar heavy damage occured in Nagasaki south of X up to 10,000 +feet, where it was stopped on a river course. + +In Hiroshima over 60,000 of 90,000 buildings were destroyed or severely +damaged by the atomic bomb; this figure represents over 67% of the +city's structures. + +In Nagasaki 14,000 or 27% of 52,000 residences were completely +destroyed and 5,400, or 10% were half destroyed. Only 12% remained +undamaged. This destruction was limited by the layout of the city. +The following is a summary of the damage to buildings in Nagasaki as +determined from a ground survey made by the Japanese: + + Destruction of Buildings and Houses Number Percentage + (Compiled by Nagasaki Municipality) + + Total in Nagasaki (before atomic explosion) 50,000 100.0 + Blasted (not burned) 2,652 5.3 + Blasted and burned 11,494 23.0 + Blasted and/or burned 14,146 28.3 + Partially burned or blasted 5,441 10.9 + Total buildings and houses destroyed 19,587 39.2 + Undamaged 30,413 60.8 + +In Hiroshima, all utilities and transportation services were disrupted +for varying lengths of time. In general however services were restored +about as rapidly as they could be used by the depleted population. +Through railroad service was in order in Hiroshima on 8 August, and +electric power was available in most of the surviving parts on 7 +August, the day after the bombing. The reservoir of the city was not +damaged, being nearly 2 miles from X. However, 70,000 breaks in water +pipes in buildings and dwellings were caused by the blast and fire +effects. Rolling transportation suffered extensive damage. The damage +to railroad tracks, and roads was comparatively small, however. The +electric power transmission and distribution systems were badly +wrecked. The telephone system was approximately 80% damaged, and no +service was restored until 15 August. + +Despite the customary Japanese lack of attention to sanitation +measures, no major epidemic broke out in the bombed cities. Although +the conditions following the bombings makes this fact seem surprising, +the experience of other bombed cities in both Germany and Japan show +Hiroshima and Nagasaki not to be isolated cases. + +The atomic explosion over Nagasaki affected an over-all area of +approximately 42.9 square miles of which about 8.5 square miles were +water and only about 9.8 square miles were built up, the remainder +being partially settled. Approximately 36% of the built up areas were +seriously damaged. The area most severely damaged had an average +radius of about 1 mile, and covered about 2.9 square miles of which 2.4 +were built up. + +In Nagasaki, buildings with structural steel frames, principally the +Mitsubishi Plant as far as 6,000 feet from X were severely damaged; +these buildings were typical of wartime mill construction in America +and Great Britain, except that some of the frames were somewhat less +substantial. The damage consisted of windows broken out (100%), steel +sashes ripped out or bent, corrugated metal or corrugated asbestos +roofs and sidings ripped off, roofs bent or destroyed, roof trusses +collapsed, columns bent and cracked and concrete foundations for +columns rotated. Damage to buildings with structural steel frames was +more severe where the buildings received the effect of the blast on +their sides than where the blast hit the ends of buildings, because the +buildings had more stiffness (resistance to negative moment at the top +of columns) in a longitudinal direction. Many of the lightly +constructed steel frame buildings collapsed completely while some of +the heavily constructed (to carry the weight of heavy cranes and loads) +were stripped of roof and siding, but the frames were only partially +injured. + +The next most seriously damaged area in Nagasaki lies outside the 2.9 +square miles just described, and embraces approximately 4.2 square +miles of which 29% was built up. The damage from blast and fire was +moderate here, but in some sections (portions of main business +districts) many secondary fires started and spread rapidly, resulting +in about as much over-all destruction as in areas much closer to X. + +An area of partial damage by blast and fire lies just outside the one +just described and comprises approximately 35.8 square miles. Of this +area, roughly 1/6th was built up and 1/4th was water. The extent of +damage varied from serious (severe damage to roofs and windows in the +main business section of Nagasaki, 2.5 miles from X), to minor (broken +or occasionally broken windows at a distance of 7 miles southeast of X). + +As intended, the bomb was exploded at an almost ideal location over +Nagasaki to do the maximum damage to industry, including the Mitsubishi +Steel and Arms Works, the Mitsubishi-Urakami Ordnance Works (Torpedo +Works), and numerous factories, factory training schools, and other +industrial establishments, with a minimum destruction of dwellings and +consequently, a minimum amount of casualties. Had the bomb been +dropped farther south, the Mitsubishi-Urakami Ordnance Works would not +have been so severely damaged, but the main business and residential +districts of Nagasaki would have sustained much greater damage +casualties. + +Calculations show that the structural steel and reinforced concrete +frames which survived the blast fairly close to X could not have +withstood the estimated peak pressures developed against the total +areas presented by the sides and roof of the buildings. The survival +of these frames is explained by the fact that they were not actually +required to withstand the peak pressure because the windows were +quickly knocked out and roof and siding stripped off thereby reducing +total area and relieving the pressure. While this saved the building +frame, it permitted severe damage to building interior and contents, +and injuries to the building occupants. Buildings without large panel +openings through which the pressure could dissipate were completely +crushed, even when their frames were as strong as those which survived. + +The damage sustained by reinforced concrete buildings depended both on +the proximity to X and the type and strength of the reinforced concrete +construction. Some of the buildings with reinforced concrete frames +also had reinforced concrete walls, ceilings, and partitions, while +others had brick or concrete tile walls covered either with plaster or +ornamental stone, with partitions of metal, glass, and plaster. With +the exception of the Nagasaki Medical School and Hospital group, which +was designed to withstand earthquakes and was therefore of heavier +construction than most American structures, most of the reinforced +concrete structures could be classified only as fair, with concrete of +low strength and density, with many of the columns, beams, and slabs +underdesigned and improperly reinforced. These facts account for some +of the structural failures which occured. + +In general, the atomic bomb explosion damaged all windows and ripped +out, bent, or twisted most of the steel window or door sashes, ripped +doors from hinges, damaged all suspended wood, metal, and plaster +ceilings. The blast concussion also caused great damage to equipment +by tumbling and battering. Fires generally of secondary origin +consumed practically all combustible material, caused plaster to crack +off, burned all wooden trim, stair covering, wooden frames of wooden +suspended ceilings, beds, mattresses, and mats, and fused glass, ruined +all equipment not already destroyed by the blast, ruined all electrical +wiring, plumbing, and caused spalling of concrete columns and beams in +many of the rooms. + +Almost without exception masonry buildings of either brick or stone +within the effective limits of the blast were severely damaged so that +most of them were flattened or reduced to rubble. The wreckage of a +church, approximately 1,800 feet east of X in Nagasaki, was one of the +few masonry buildings still recognizable and only portions of the walls +of this structure were left standing. These walls were extremely thick +(about 2 feet). The two domes of the church had reinforced concrete +frames and although they were toppled, they held together as units. + +Practically every wooden building or building with timber frame within +2.0 miles of X was either completely destroyed or very seriously +damaged, and significant damage in Nagasaki resulted as far as 3 miles +from X. Nearly all such buildings collapsed and a very large number +were consumed by fire. + +A reference to the various photographs depicting damage shows that +although most of the buildings within the effective limits of the blast +were totally destroyed or severely damaged, a large number of chimneys +even close to X were left standing, apparently uninjured by the +concussion. One explanation is that concrete chimneys are +approximately cylindrical in shape and consequently offer much less +wind resistance than flat surfaces such as buildings. Another +explanation is that since the cities were subject to typhoons the more +modern chimneys were probably designed to withstand winds of high +velocity. It is also probable that most of the recently constructed +chimneys as well as the more modern buildings were constructed to +withstand the acceleration of rather severe earthquakes. Since the +bombs were exploded high in the air, chimneys relatively close to X +were subjected to more of a downward than a lateral pressure, and +consequently the overturning moment was much less than might have been +anticipated. + +Although the blast damaged many bridges to some extent, bridge damage +was on the whole slight in comparison to that suffered by buildings. +The damage varied from only damaged railings to complete destruction of +the superstructure. Some of the bridges were wrecked and the spans +were shoved off their piers and into the river bed below by the force +of the blast. Others, particularly steel plate girder bridges, were +badly buckled by the blast pressure. None of the failures observed +could be attributed to inadequate design or structural weaknesses. + +The roads, and railroad and street railway trackage sustained +practically no primary damage as a result of the explosion. Most of +the damage to railroads occurred from secondary causes, such as fires +and damage to bridges or other structures. Rolling stock, as well as +automobiles, trolleys, and buses were destroyed and burned up to a +considerable distance from X. Streets were impassable for awhile +because of the debris, but they were not damaged. The height of the +bomb explosion probably explains the absence of direct damage to +railroads and roads. + +A large part of the electric supply was interrupted by the bomb blast +chiefly through damage to electric substations and overhead +transmission systems. Both gas works in Nagasaki were severely damaged +by the bomb. These works would have required 6-7 months to get into +operation. In addition to the damage sustained by the electrical and +gas systems, severe damage to the water supply system was reported by +the Japanese government; the chief damage was a number of breaks in the +large water mains and in almost all of the distributing pipes in the +areas which were affected by the blast. Nagasaki was still suffering +from a water shortage inside the city six weeks after the atomic attack. + +The Nagasaki Prefectural report describes vividly the effects of the +bomb on the city and its inhabitants: + +"Within a radius of 1 kilometer from X, men and animals died almost +instantaneously and outside a radius of 1 kilometer and within a radius +of 2 kilometers from X, some men and animals died instantly from the +great blast and heat but the great majority were seriously or +superficially injured. Houses and other structures were completely +destroyed while fires broke out everywhere. Trees were uprooted and +withered by the heat. + +"Outside a radius of 2 kilometers and within a radius of 4 kilometers +from X, men and animals suffered various degrees of injury from window +glass and other fragments scattered about by the blast and many were +burned by the intense heat. Dwellings and other structures were half +damaged by blast. + +"Outside a radius of 4 kilometers and within a radius of 8 kilometers +living creatures were injured by materials blown about by the blast; +the majority were only superficially wounded. Houses were only half or +partially damaged." + +The British Mission to Japan interpreted their observations of the +destruction of buildings to apply to similar construction of their own +as follows: + +A similar bomb exploding in a similar fashion would produce the +following effects on normal British houses: + +Up to 1,000 yards from X it would cause complete collapse. + +Up to 1 mile from X it would damage the houses beyond repair. + +Up to 1.5 miles from X it would render them uninhabitable without +extensive repair, particularly to roof timbers. + +Up to 2.5 miles from X it would render them uninhabitable until +first-aid repairs had been carried out. + +The fire damage in both cities was tremendous, but was more complete in +Hiroshima than in Nagasaki. The effect of the fires was to change +profoundly the appearance of the city and to leave the central part +bare, except for some reinforced concrete and steel frames and objects +such as safes, chimney stacks, and pieces of twisted sheet metal. The +fire damage resulted more from the properties of the cities themselves +than from those of the bombs. + +The conflagration in Hiroshima caused high winds to spring up as air +was drawn in toward the center of the burning area, creating a "fire +storm". The wind velocity in the city had been less than 5 miles per +hour before the bombing, but the fire-wind attained a velocity of 30-40 +miles per hour. These great winds restricted the perimeter of the fire +but greatly added to the damage of the conflagration within the +perimeter and caused the deaths of many persons who might otherwise +have escaped. In Nagasaki, very severe damage was caused by fires, but +no extensive "fire storm" engulfed the city. In both cities, some of +the fires close to X were no doubt started by the ignition of highly +combustible material such as paper, straw, and dry cloth, upon the +instantaneous radiation of heat from the nuclear explosion. The +presence of large amounts of unburnt combustible materials near X, +however, indicated that even though the heat of the blast was very +intense, its duration was insufficient to raise the temperature of many +materials to the kindling point except in cases where conditions were +ideal. The majority of the fires were of secondary origin starting +from the usual electrical short-circuits, broken gas lines, overturned +stoves, open fires, charcoal braziers, lamps, etc., following collapse +or serious damage from the direct blast. + +Fire fighting and rescue units were stripped of men and equipment. +Almost 30 hours elapsed before any rescue parties were observable. In +Hiroshima only a handful of fire engines were available for fighting +the ensuing fires, and none of these were of first class type. In any +case, however, it is not likely that any fire fighting equipment or +personnel or organization could have effected any significant reduction +in the amount of damage caused by the tremendous conflagration. + +A study of numerous aerial photographs made prior to the atomic +bombings indicates that between 10 June and 9 August 1945 the Japanese +constructed fire breaks in certain areas of the cities in order to +control large scale fires. In general these fire breaks were not +effective because fires were started at so many locations +simultaneously. They appear, however, to have helped prevent fires +from spreading farther east into the main business and residential +section of Nagasaki. + + + +TOTAL CASUALTIES + +There has been great difficulty in estimating the total casualties in +the Japanese cities as a result of the atomic bombing. The extensive +destruction of civil installations (hospitals, fire and police +department, and government agencies) the state of utter confusion +immediately following the explosion, as well as the uncertainty +regarding the actual population before the bombing, contribute to the +difficulty of making estimates of casualties. The Japanese periodic +censuses are not complete. Finally, the great fires that raged in each +city totally consumed many bodies. + +The number of total casualties has been estimated at various times +since the bombings with wide discrepancies. The Manhattan Engineer +District's best available figures are: + + TABLE A + Estimates of Casualties + + Hiroshima Nagasaki + Pre-raid population 255,000 195,000 + Dead 66,000 39,000 + Injured 69,000 25,000 + Total Casualties 135,000 64,000 + +The relation of total casualties to distance from X, the center of +damage and point directly under the air-burst explosion of the bomb, is +of great importance in evaluating the casualty-producing effect of the +bombs. This relationship for the total population of Nagasaki is shown +in the table below, based on the first-obtained casualty figures of the +District: + + TABLE B + Relation of Total Casualties to Distance from X + + Distance Total Killed per + from X, feet Killed Injured Missing Casualties square mile + 0 - 1,640 7,505 960 1,127 9,592 24,700 + 1,640 - 3,300 3,688 1,478 1,799 6,965 4,040 + 3,300 - 4,900 8,678 17,137 3,597 29,412 5,710 + 4,900 - 6,550 221 11,958 28 12,207 125 + 6,550 - 9,850 112 9,460 17 9,589 20 + +No figure for total pre-raid population at these different distances +were available. Such figures would be necessary in order to compute +per cent mortality. A calculation made by the British Mission to Japan +and based on a preliminary analysis of the study of the Joint +Medical-Atomic Bomb Investigating Commission gives the following +calculated values for per cent mortality at increasing distances from X: + + TABLE C + Per-Cent Mortality at Various Distances + + Distance from X, Per-cent Mortality + in feet + 0 - 1000 93.0% + 1000 - 2000 92.0 + 2000 - 3000 86.0 + 3000 - 4000 69.0 + 4000 - 5000 49.0 + 5000 - 6000 31.5 + 6000 - 7000 12.5 + 7000 - 8000 1.3 + 8000 - 9000 0.5 + 9000 - 10,000 0.0 + +It seems almost certain from the various reports that the greatest +total number of deaths were those occurring immediately after the +bombing. The causes of many of the deaths can only be surmised, and of +course many persons near the center of explosion suffered fatal +injuries from more than one of the bomb effects. The proper order of +importance for possible causes of death is: burns, mechanical injury, +and gamma radiation. Early estimates by the Japanese are shown in D +below: + + TABLE D + Cause of Immediate Deaths + + City Cause of Death Per-cent of Total + Hiroshima Burns 60% + Falling debris 30 + Other 10 + + Nagasaki Burns 95% + Falling debris 9 + Flying glass 7 + Other 7 + + + +THE NATURE OF AN ATOMIC EXPLOSION + +The most striking difference between the explosion of an atomic bomb +and that of an ordinary T.N.T. bomb is of course in magnitude; as the +President announced after the Hiroshima attack, the explosive energy of +each of the atomic bombs was equivalent to about 20,000 tons of T.N.T. + +But in addition to its vastly greater power, an atomic explosion has +several other very special characteristics. Ordinary explosion is a +chemical reaction in which energy is released by the rearrangement of +the atoms of the explosive material. In an atomic explosion the +identity of the atoms, not simply their arrangement, is changed. A +considerable fraction of the mass of the explosive charge, which may be +uranium 235 or plutonium, is transformed into energy. Einstein's +equation, E = mc^2, shows that matter that is transformed into energy +may yield a total energy equivalent to the mass multiplied by the +square of the velocity of light. The significance of the equation is +easily seen when one recalls that the velocity of light is 186,000 +miles per second. The energy released when a pound of T.N.T. explodes +would, if converted entirely into heat, raise the temperature of 36 +lbs. of water from freezing temperature (32 deg F) to boiling +temperature (212 deg F). The nuclear fission of a pound of uranium +would produce an equal temperature rise in over 200 million pounds of +water. + +The explosive effect of an ordinary material such as T.N.T. is derived +from the rapid conversion of solid T.N.T. to gas, which occupies +initially the same volume as the solid; it exerts intense pressures on +the surrounding air and expands rapidly to a volume many times larger +than the initial volume. A wave of high pressure thus rapidly moves +outward from the center of the explosion and is the major cause of +damage from ordinary high explosives. An atomic bomb also generates a +wave of high pressure which is in fact of, much higher pressure than +that from ordinary explosions; and this wave is again the major cause +of damage to buildings and other structures. It differs from the +pressure wave of a block buster in the size of the area over which high +pressures are generated. It also differs in the duration of the +pressure pulse at any given point: the pressure from a blockbuster +lasts for a few milliseconds (a millisecond is one thousandth of a +second) only, that from the atomic bomb for nearly a second, and was +felt by observers both in Japan and in New Mexico as a very strong wind +going by. + +The next greatest difference between the atomic bomb and the T.N.T. +explosion is the fact that the atomic bomb gives off greater amounts of +radiation. Most of this radiation is "light" of some wave-length +ranging from the so-called heat radiations of very long wave length to +the so-called gamma rays which have wave-lengths even shorter than the +X-rays used in medicine. All of these radiations travel at the same +speed; this, the speed of light, is 186,000 miles per second. The +radiations are intense enough to kill people within an appreciable +distance from the explosion, and are in fact the major cause of deaths +and injuries apart from mechanical injuries. The greatest number of +radiation injuries was probably due to the ultra-violet rays which have +a wave length slightly shorter than visible light and which caused +flash burn comparable to severe sunburn. After these, the gamma rays +of ultra short wave length are most important; these cause injuries +similar to those from over-doses of X-rays. + +The origin of the gamma rays is different from that of the bulk of the +radiation: the latter is caused by the extremely high temperatures in +the bomb, in the same way as light is emitted from the hot surface of +the sun or from the wires in an incandescent lamp. The gamma rays on +the other hand are emitted by the atomic nuclei themselves when they +are transformed in the fission process. The gamma rays are therefore +specific to the atomic bomb and are completely absent in T.N.T. +explosions. The light of longer wave length (visible and ultra-violet) +is also emitted by a T.N.T. explosion, but with much smaller intensity +than by an atomic bomb, which makes it insignificant as far as damage +is concerned. + +A large fraction of the gamma rays is emitted in the first few +microseconds (millionths of a second) of the atomic explosion, together +with neutrons which are also produced in the nuclear fission. The +neutrons have much less damage effect than the gamma rays because they +have a smaller intensity and also because they are strongly absorbed in +air and therefore can penetrate only to relatively small distances from +the explosion: at a thousand yards the neutron intensity is negligible. +After the nuclear emission, strong gamma radiation continues to come +from the exploded bomb. This generates from the fission products and +continues for about one minute until all of the explosion products have +risen to such a height that the intensity received on the ground is +negligible. A large number of beta rays are also emitted during this +time, but they are unimportant because their range is not very great, +only a few feet. The range of alpha particles from the unused active +material and fissionable material of the bomb is even smaller. + +Apart from the gamma radiation ordinary light is emitted, some of which +is visible and some of which is the ultra violet rays mainly +responsible for flash burns. The emission of light starts a few +milliseconds after the nuclear explosion when the energy from the +explosion reaches the air surrounding the bomb. The observer sees then +a ball of fire which rapidly grows in size. During most of the early +time, the ball of fire extends as far as the wave of high pressure. As +the ball of fire grows its temperature and brightness decrease. +Several milliseconds after the initiation of the explosion, the +brightness of the ball of fire goes through a minimum, then it gets +somewhat brighter and remains at the order of a few times the +brightness of the sun for a period of 10 to 15 seconds for an observer +at six miles distance. Most of the radiation is given off after this +point of maximum brightness. Also after this maximum, the pressure +waves run ahead of the ball of fire. + +The ball of fire rapidly expands from the size of the bomb to a radius +of several hundred feet at one second after the explosion. After this +the most striking feature is the rise of the ball of fire at the rate +of about 30 yards per second. Meanwhile it also continues to expand by +mixing with the cooler air surrounding it. At the end of the first +minute the ball has expanded to a radius of several hundred yards and +risen to a height of about one mile. The shock wave has by now reached +a radius of 15 miles and its pressure dropped to less than 1/10 of a +pound per square inch. The ball now loses its brilliance and appears +as a great cloud of smoke: the pulverized material of the bomb. This +cloud continues to rise vertically and finally mushrooms out at an +altitude of about 25,000 feet depending upon meteorological conditions. +The cloud reaches a maximum height of between 50,000 and 70,000 feet in +a time of over 30 minutes. + +It is of interest to note that Dr. Hans Bethe, then a member of the +Manhattan Engineer District on loan from Cornell University, predicted +the existence and characteristics of this ball of fire months before +the first test was carried out. + +To summarize, radiation comes in two bursts--an extremely intense one +lasting only about 3 milliseconds and a less intense one of much longer +duration lasting several seconds. The second burst contains by far the +larger fraction of the total light energy, more than 90%. But the +first flash is especially large in ultra-violet radiation which is +biologically more effective. Moreover, because the heat in this flash +comes in such a short time, there is no time for any cooling to take +place, and the temperature of a person's skin can be raised 50 degrees +centigrade by the flash of visible and ultra-violet rays in the first +millisecond at a distance of 4,000 yards. People may be injured by +flash burns at even larger distances. Gamma radiation danger does not +extend nearly so far and neutron radiation danger is still more limited. + +The high skin temperatures result from the first flash of high +intensity radiation and are probably as significant for injuries as the +total dosages which come mainly from the second more sustained burst of +radiation. The combination of skin temperature increase plus large +ultra-violet flux inside 4,000 yards is injurious in all cases to +exposed personnel. Beyond this point there may be cases of injury, +depending upon the individual sensitivity. The infra-red dosage is +probably less important because of its smaller intensity. + + + +CHARACTERISTICS OF THE DAMAGE CAUSED BY THE ATOMIC BOMBS + +The damage to man-made structures caused by the bombs was due to two +distinct causes: first the blast, or pressure wave, emanating from the +center of the explosion, and, second, the fires which were caused +either by the heat of the explosion itself or by the collapse of +buildings containing stoves, electrical fixtures, or any other +equipment which might produce what is known as a secondary fire, and +subsequent spread of these fires. + +The blast produced by the atomic bomb has already been stated to be +approximately equivalent to that of 20,000 tons of T.N.T. Given this +figure, one may calculate the expected peak pressures in the air, at +various distances from the center of the explosion, which occurred +following detonation of the bomb. The peak pressures which were +calculated before the bombs were dropped agreed very closely with those +which were actually experienced in the cities during the attack as +computed by Allied experts in a number of ingenious ways after the +occupation of Japan. + +The blast of pressure from the atomic bombs differed from that of +ordinary high explosive bombs in three main ways: + +A. Downward thrust. Because the explosions were well up in the air, +much of the damage resulted from a downward pressure. This pressure of +course most largely effected flat roofs. Some telegraph and other +poles immediately below the explosion remained upright while those at +greater distances from the center of damage, being more largely exposed +to a horizontal thrust from the blast pressure waves, were overturned +or tilted. Trees underneath the explosion remained upright but had +their branches broken downward. + +B. Mass distortion of buildings. An ordinary bomb can damage only a +part of a large building, which may then collapse further under the +action of gravity. But the blast wave from an atomic bomb is so large +that it can engulf whole buildings, no matter how great their size, +pushing them over as though a giant hand had given them a shove. + +C. Long duration of the positive pressure pulse and consequent small +effect of the negative pressure, or suction, phase. In any explosion, +the positive pressure exerted by the blast lasts for a definite period +of time (usually a small fraction of a second) and is then followed by +a somewhat longer period of negative pressure, or suction. The +negative pressure is always much weaker than the positive, but in +ordinary explosions the short duration of the positive pulse results in +many structures not having time to fail in that phase, while they are +able to fail under the more extended, though weaker, negative pressure. +But the duration of the positive pulse is approximately proportional to +the 1/3 power of the size of the explosive charge. Thus, if the +relation held true throughout the range in question, a 10-ton T.N.T. +explosion would have a positive pulse only about 1/14th as long as that +of a 20,000-ton explosion. Consequently, the atomic explosions had +positive pulses so much longer then those of ordinary explosives that +nearly all failures probably occurred during this phase, and very +little damage could be attributed to the suction which followed. + +One other interesting feature was the combination of flash ignition and +comparative slow pressure wave. Some objects, such as thin, dry wooden +slats, were ignited by the radiated flash heat, and then their fires +were blown out some time later (depending on their distance from X) by +the pressure blast which followed the flash radiation. + + + +CALCULATIONS OF THE PEAK PRESSURE OF THE BLAST WAVE + +Several ingenious methods were used by the various investigators to +determine, upon visiting the wrecked cities, what had actually been the +peak pressures exerted by the atomic blasts. These pressures were +computed for various distances from X, and curves were then plotted +which were checked against the theoretical predictions of what the +pressures would be. A further check was afforded from the readings +obtained by the measuring instruments which were dropped by parachute +at each atomic attack. The peak pressure figures gave a direct clue to +the equivalent T.N.T. tonnage of the atomic bombs, since the pressures +developed by any given amount of T.N.T. can be calculated easily. + +One of the simplest methods of estimating the peak pressure is from +crushing of oil drums, gasoline cans, or any other empty thin metal +vessel with a small opening. The assumption made is that the blast +wave pressure comes on instantaneously, the resulting pressure on the +can is more than the case can withstand, and the walls collapse inward. +The air inside is compressed adiabatically to such a point that the +pressure inside is less by a certain amount than the pressure outside, +this amount being the pressure difference outside and in that the walls +can stand in their crumpled condition. The uncertainties involved are, +first, that some air rushes in through any opening that the can may +have, and thus helps to build up the pressure inside; and, second, that +as the pressure outside falls, the air inside cannot escape +sufficiently fast to avoid the walls of the can being blown out again +to some extent. These uncertainties are such that estimates of +pressure based on this method are on the low side, i.e., they are +underestimated. + +Another method of calculating the peak-pressure is through the bending +of steel flagpoles, or lightning conductors, away from the explosion. +It is possible to calculate the drag on a pole or rod in an airstream +of a certain density and velocity; by connecting this drag with the +strength of the pole in question, a determination of the pressure wave +may be obtained. + +Still another method of estimating the peak pressure is through the +overturning of memorial stones, of which there are a great quantity in +Japan. The dimensions of the stones can be used along with known data +on the pressure exerted by wind against flat surfaces, to calculate the +desired figure. + + + +LONG RANGE BLAST DAMAGE + +There was no consistency in the long range blast damage. Observers +often thought that they had found the limit, and then 2,000 feet +farther away would find further evidence of damage. + +The most impressive long range damage was the collapse of some of the +barracks sheds at Kamigo, 23,000 feet south of X in Nagasaki. It was +remarkable to see some of the buildings intact to the last details, +including the roof and even the windows, and yet next to them a similar +building collapsed to ground level. + +The limiting radius for severe displacement of roof tiles in Nagasaki +was about 10,000 feet although isolated cases were found up to 16,000 +feet. In Hiroshima the general limiting radius was about 8,000 feet; +however, even at a distance of 26,000 feet from X in Hiroshima, some +tiles were displaced. + +At Mogi, 7 miles from X in Nagasaki, over steep hills over 600 feet +high, about 10% of the glass came out. In nearer, sequestered +localities only 4 miles from X, no damage of any kind was caused. An +interesting effect was noted at Mogi; eyewitnesses said that they +thought a raid was being made on the place; one big flash was seen, +then a loud roar, followed at several second intervals by half a dozen +other loud reports, from all directions. These successive reports were +obviously reflections from the hills surrounding Mogi. + + + +GROUND SHOCK + +The ground shock in most cities was very light. Water pipes still +carried water and where leaks were visible they were mainly above +ground. Virtually all of the damage to underground utilities was +caused by the collapse of buildings rather than by any direct exertion +of the blast pressure. This fact of course resulted from the bombs' +having been exploded high in the air. + + + +SHIELDING, OR SCREENING FROM BLAST + +In any explosion, a certain amount of protection from blast may be +gained by having any large and substantial object between the protected +object and the center of the explosion. This shielding effect was +noticeable in the atomic explosions, just as in ordinary cases, +although the magnitude of the explosions and the fact that they +occurred at a considerable height in the air caused marked differences +from the shielding which would have characterized ordinary bomb +explosions. + +The outstanding example of shielding was that afforded by the hills in +the city of Nagasaki; it was the shielding of these hills which +resulted in the smaller area of devastation in Nagasaki despite the +fact that the bomb used there was not less powerful. The hills gave +effective shielding only at such distances from the center of explosion +that the blast pressure was becoming critical--that is, was only barely +sufficient to cause collapse--for the structure. Houses built in +ravines in Nagasaki pointing well away from the center of the explosion +survived without damage, but others at similar distances in ravines +pointing toward the center of explosion were greatly damaged. In the +north of Nagasaki there was a small hamlet about 8,000 feet from the +center of explosion; one could see a distinctive variation in the +intensity of damage across the hamlet, corresponding with the shadows +thrown by a sharp hill. + +The best example of shielding by a hill was southeast of the center of +explosion in Nagasaki. The damage at 8,000 feet from X consisted of +light plaster damage and destruction of about half the windows. These +buildings were of European type and were on the reverse side of a steep +hill. At the same distance to the south-southeast the damage was +considerably greater, i.e., all windows and frames, doors, were damaged +and heavy plaster damage and cracks in the brick work also appeared. +The contrast may be illustrated also by the fact that at the Nagasaki +Prefectural office at 10,800 feet the damage was bad enough for the +building to be evacuated, while at the Nagasaki Normal School to which +the Prefectural office had been moved, at the same distance, the damage +was comparatively light. + +Because of the height of the bursts no evidence was expected of the +shielding of one building by another, at least up to a considerable +radius. It was in fact difficult to find any evidence at any distance +of such shielding. There appeared to have been a little shielding of +the building behind the Administration Building of the Torpedo Works in +Nagasaki, but the benefits were very slight. There was also some +evidence that the group of buildings comprising the Medical School in +Nagasaki did afford each other mutual protection. On the whole, +however, shielding of one building by another was not noticeable. + +There was one other peculiar type of shielding, best exhibited by the +workers' houses to the north of the torpedo plant in Nagasaki. These +were 6,000 to 7,000 feet north of X. The damage to these houses was +not nearly as bad as those over a thousand feet farther away from the +center of explosion. It seemed as though the great destruction caused +in the torpedo plant had weakened the blast a little, and the full +power was not restored for another 1,000 feet or more. + + + +FLASH BURN + +As already stated, a characteristic feature of the atomic bomb, which +is quite foreign to ordinary explosives, is that a very appreciable +fraction of the energy liberated goes into radiant heat and light. For +a sufficiently large explosion, the flash burn produced by this +radiated energy will become the dominant cause of damage, since the +area of burn damage will increase in proportion to the energy released, +whereas the area of blast damage increases only with the two-thirds +power of the energy. Although such a reversal of the mechanism of +damage was not achieved in the Hiroshima and Nagasaki bombs, the +effects of the flash were, however, very evident, and many casualties +resulted from flash burns. A discussion of the casualties caused by +flash burns will be given later; in this section will be described the +other flash effects which were observed in the two cities. + +The duration of the heat radiation from the bomb is so short, just a +few thousandths of a second, that there is no time for the energy +falling on a surface to be dissipated by thermal defusion; the flash +burn is typically a surface effect. In other words the surface of +either a person or an object exposed to the flash is raised to a very +high temperature while immediately beneath the surface very little rise +in temperature occurs. + +The flash burning of the surface of objects, particularly wooden +objects, occurred in Hiroshima up to a radius of 9,500 feet from X; at +Nagasaki burns were visible up to 11,000 feet from X. The charring and +blackening of all telephone poles, trees and wooden posts in the areas +not destroyed by the general fire occurred only on the side facing the +center of explosion and did not go around the corners of buildings or +hills. The exact position of the explosion was in fact accurately +determined by taking a number of sights from various objects which had +been flash burned on one side only. + +To illustrate the effects of the flash burn, the following describes a +number of examples found by an observer moving northward from the +center of explosion in Nagasaki. First occurred a row of fence posts +at the north edge of the prison hill, at 0.3 miles from X. The top and +upper part of these posts were heavily charred. The charring on the +front of the posts was sharply limited by the shadow of a wall. This +wall had however been completely demolished by the blast, which of +course arrived some time after the flash. At the north edge of the +Torpedo works, 1.05 miles from X, telephone poles were charred to a +depth of about 0.5 millimeters. A light piece of wood similar to the +flat side of an orange crate, was found leaning against one of the +telephone poles. Its front surface was charred the same way as the +pole, but it was evident that it had actually been ignited. The wood +was blackened through a couple of cracks and nail holes, and around the +edges onto the back surface. It seemed likely that this piece of wood +had flamed up under the flash for a few seconds before the flame was +blown out by the wind of the blast. Farther out, between 1.05 and 1.5 +miles from the explosion, were many trees and poles showing a +blackening. Some of the poles had platforms near the top. The shadows +cast by the platforms were clearly visible and showed that the bomb had +detonated at a considerable height. The row of poles turned north and +crossed the mountain ridge; the flash burn was plainly visible all the +way to the top of the ridge, the farthest burn observed being at 2.0 +miles from X. + +Another striking effect of the flash burn was the autumnal appearance +of the bowl formed by the hills on three sides of the explosion point. +The ridges are about 1.5 miles from X. Throughout this bowl the +foliage turned yellow, although on the far side of the ridges the +countryside was quite green. This autumnal appearance of the trees +extended to about 8,000 feet from X. + +However, shrubs and small plants quite near the center of explosion in +Hiroshima, although stripped of leaves, had obviously not been killed. +Many were throwing out new buds when observers visited the city. + +There are two other remarkable effects of the heat radiated from the +bomb explosion. The first of these is the manner in which heat +roughened the surface of polished granite, which retained its polish +only where it was shielded from the radiated heat travelling in +straight lines from the explosion. This roughening by radiated heat +caused by the unequal expansion of the constituent crystals of the +stone; for granite crystals the melting temperature is about 600 deg +centigrade. Therefore the depth of roughening and ultimate flaking of +the granite surface indicated the depth to which this temperature +occurred and helped to determine the average ground temperatures in the +instant following the explosion. This effect was noted for distances +about 1 1/2 times as great in Nagasaki as in Hiroshima. + +The second remarkable effect was the bubbling of roof tile. The size +of the bubbles and their extent was proportional to their nearness to +the center of explosion and also depended on how squarely the tile +itself was faced toward the explosion. The distance ratio of this +effect between Nagasaki and Hiroshima was about the same as for the +flaking of polished granite. + +Various other effects of the radiated heat were noted, including the +lightening of asphalt road surfaces in spots which had not been +protected from the radiated heat by any object such as that of a person +walking along the road. Various other surfaces were discolored in +different ways by the radiated heat. + +As has already been mentioned the fact that radiant heat traveled only +in straight lines from the center of explosion enabled observers to +determine the direction toward the center of explosion from a number of +different points, by observing the "shadows" which were cast by +intervening objects where they shielded the otherwise exposed surface +of some object. Thus the center of explosion was located with +considerable accuracy. In a number of cases these "shadows" also gave +an indication of the height of burst of the bomb and occasionally a +distinct penumbra was found which enabled observers to calculate the +diameter of the ball of fire at the instant it was exerting the maximum +charring or burning effect. + +One more interesting feature connected with heat radiation was the +charring of fabric to different degrees depending upon the color of the +fabric. A number of instances were recorded in which persons wearing +clothing of various colors received burns greatly varying in degree, +the degree of burn depending upon the color of the fabric over the skin +in question. For example a shirt of alternate light and dark gray +stripes, each about 1/8 of an inch wide, had the dark stripes +completely burned out but the light stripes were undamaged; and a piece +of Japanese paper exposed nearly 1 1/2 miles from X had the characters +which were written in black ink neatly burned out. + + + +CHARACTERISTICS OF THE INJURIES TO PERSONS + +Injuries to persons resulting from the atomic explosions were of the +following types: + + A. Burns, from + 1. Flash radiation of heat + 2. Fires started by the explosions. + B. Mechanical injuries from collapse of buildings, flying debris, etc. + C. Direct effects of the high blast pressure, i.e., straight + compression. + D. Radiation injuries, from the instantaneous emission of gamma rays and + neutrons. + +It is impossible to assign exact percentages of casualties to each of +the types of injury, because so many victims were injured by more than +one effect of the explosions. However, it is certain that the greater +part of the casualties resulted from burns and mechanical injures. +Col. Warren, one of America's foremost radioligists, stated it is +probable that 7 per cent or less of the deaths resulted primarily from +radiation disease. + +The greatest single factor influencing the occurrence of casualties was +the distance of the person concerned from the center of explosion. + +Estimates based on the study of a selected group of 900 patients +indicated that total casualties occurred as far out as 14,000 feet at +Nagasaki and 12,000 feet at Hiroshima. + +Burns were suffered at a considerable greater distance from X than any +other type of injury, and mechanical injuries farther out than +radiation effects. + +Medical findings show that no person was injured by radioactivity who +was not exposed to the actual explosion of the bombs. No injuries +resulted from persistent radioactivity of any sort. + + + +BURNS + +Two types of burns were observed. These are generally differentiated +as flame or fire burn and so-called flash burn. + +The early appearance of the flame burn as reported by the Japanese, and +the later appearance as observed, was not unusual. + +The flash burn presented several distinctive features. Marked redness +of the affected skin areas appeared almost immediately, according to +the Japanese, with progressive changes in the skin taking place over a +period of a few hours. When seen after 50 days, the most distinctive +feature of these burns was their sharp limitation to exposed skin areas +facing the center of the explosion. For instance, a patient who had +been walking in a direction at right angles to a line drawn between him +and the explosion, and whose arms were swinging, might have burns only +on the outside of the arm nearest the center and on the inside of the +other arm. + +Generally, any type of shielding protected the skin against flash +burns, although burns through one, and very occasionally more, layers +of clothing did occur in patients near the center. In such cases, it +was not unusual to find burns through black but not through white +clothing, on the same patient. Flash burns also tended to involve +areas where the clothes were tightly drawn over the skin, such as at +the elbows and shoulders. + +The Japanese report the incidence of burns in patients surviving more +than a few hours after the explosion, and seeking medical attention, as +high as 95%. The total mortalities due to burns alone cannot be +estimated with any degree of accuracy. As mentioned already, it is +believed that the majority of all the deaths occurred immediately. Of +these, the Japanese estimate that 75%, and most of the reports estimate +that over 50%, of the deaths were due to burns. + +In general, the incidence of burns was in direct proportion to the +distance from X. However, certain irregularities in this relationship +result in the medical studies because of variations in the amount of +shielding from flash burn, and because of the lack of complete data on +persons killed outright close to X. + +The maximum distance from X at which flash burns were observed is of +paramount interest. It has been estimated that patients with burns at +Hiroshima were all less than 7,500 feet from the center of the +explosion at the time of the bombing. At Nagasaki, patients with burns +were observed out to the remarkable distance of 13,800 feet. + + + +MECHANICAL INJURIES + +The mechanical injuries included fractures, lacerations, contusions, +abrasions, and other effects to be expected from falling roofs, +crumbling walls, flying debris and glass, and other indirect blast +effects. The appearance of these various types of mechanical injuries +was not remarkable to the medical authorities who studied them. + +It was estimated that patients with lacerations at Hiroshima were less +than 10,600 feet from X, whereas at Nagasaki they extended as far as +12,200 feet. + +The tremendous drag of wind, even as far as 1 mile from X, must have +resulted in many injuries and deaths. Some large pieces of a prison +wall, for example, were flung 80 feet, and many have gone 30 feet high +before falling. The same fate must have befallen many persons, and the +chances of a human being surviving such treatment are probably small. + + + +BLAST INJURIES + +No estimate of the number of deaths or early symptoms due to blast +pressure can be made. The pressures developed on the ground under the +explosions were not sufficient to kill more than those people very near +the center of damage (within a few hundred feet at most). Very few +cases of ruptured ear drums were noted, and it is the general feeling +of the medical authorities that the direct blast effects were not +great. Many of the Japanese reports, which are believed to be false, +describe immediate effects such as ruptured abdomens with protruding +intestines and protruding eyes, but no such results were actually +traced to the effect of air pressure alone. + + + +RADIATION INJURIES + +As pointed out in another section of this report the radiations from +the nuclear explosions which caused injuries to persons were primarily +those experienced within the first second after the explosion; a few +may have occurred later, but all occurred in the first minute. The +other two general types of radiation, viz., radiation from scattered +fission products and induced radioactivity from objects near the center +of explosion, were definitely proved not to have caused any casualties. + +The proper designation of radiation injuries is somewhat difficult. +Probably the two most direct designations are radiation injury and +gamma ray injury. The former term is not entirely suitable in that it +does not define the type of radiation as ionizing and allows possible +confusion with other types of radiation (e.g., infra-red). The +objection to the latter term is that it limits the ionizing radiation +to gamma rays, which were undoubtedly the most important; but the +possible contribution of neutron and even beta rays to the biological +effects cannot be entirely ignored. Radiation injury has the advantage +of custom, since it is generally understood in medicine to refer to +X-ray effect as distinguished from the effects of actinic radiation. +Accordingly, radiation injury is used in this report to mean injury due +only to ionizing radiation. + +According to Japanese observations, the early symptons in patients +suffering from radiation injury closely resembled the symptons observed +in patients receiving intensive roentgen therapy, as well as those +observed in experimental animals receiving large doses of X-rays. The +important symptoms reported by the Japanese and observed by American +authorities were epilation (lose of hair), petechiae (bleeding into the +skin), and other hemorrhagic manifestations, oropharyngeal lesions +(inflammation of the mouth and throat), vomiting, diarrhea, and fever. + +Epilation was one of the most spectacular and obvious findings. The +appearance of the epilated patient was typical. The crown was involved +more than the sides, and in many instances the resemblance to a monk's +tonsure was striking. In extreme cases the hair was totally lost. In +some cases, re-growth of hair had begun by the time patients were seen +50 days after the bombing. Curiously, epilation of hair other than +that of the scalp was extremely unusual. + +Petechiae and other hemorrhagic manifestations were striking findings. +Bleeding began usually from the gums and in the more seriously affected +was soon evident from every possible source. Petechiae appeared on the +limbs and on pressure points. Large ecchymoses (hemorrhages under the +skin) developed about needle punctures, and wounds partially healed +broke down and bled freely. Retinal hemorrhages occurred in many of +the patients. The bleeding time and the coagulation time were +prolonged. The platelets (coagulation of the blood) were +characteristically reduced in numbers. + +Nausea and vomiting appearing within a few hours after the explosion +was reported frequently by the Japanese. This usually had subsided by +the following morning, although occasionally it continued for two or +three days. Vomiting was not infrequently reported and observed during +the course of the later symptoms, although at these times it generally +appeared to be related to other manifestation of systemic reactions +associated with infection. + +Diarrhea of varying degrees of severity was reported and observed. In +the more severe cases, it was frequently bloody. For reasons which are +not yet clear, the diarrhea in some cases was very persistent. + +Lesions of the gums, and the oral mucous membrane, and the throat were +observed. The affected areas became deep red, then violacious in +color; and in many instances ulcerations and necrosis (breakdown of +tissue) followed. Blood counts done and recorded by the Japanese, as +well as counts done by the Manhattan Engineer District Group, on such +patients regularly showed leucopenia (low-white blood cell count). In +extreme cases the white blood cell count was below 1,000 (normal count +is around 7,000). In association with the leucopenia and the +oropharyngeal lesions, a variety of other infective processes were +seen. Wounds and burns which were healing adequately suppurated and +serious necrosis occurred. At the same time, similar ulcerations were +observed in the larynx, bowels, and in females, the gentalia. Fever +usually accompanied these lesions. + +Eye injuries produced by the atomic bombings in both cities were the +subject of special investigations. The usual types of mechanical +injuries were seen. In addition, lesions consisting of retinal +hemorrhage and exudation were observed and 75% of the patients showing +them had other signs of radiation injury. + +The progress of radiation disease of various degrees of severity is +shown in the following table: + + Summary of Radiation Injury + Clinical Symptoms and Findings + + Day + after + Explo- + sion Most Severe Moderately Severe Mild + 1. 1. Nausea and vomiting 1. Nausea and vomiting + 2. after 1-2 hours. after 1-2 hours. + 3. NO DEFINITE SYMPTOMS + 4. + 5. 2. Diarrhea + 6. 3. Vomiting NO DEFINITE SYMPTOMS + 7. 4. Inflammation of the + mouth and throat + 8. 5. Fever + 9. 6. Rapid emaciation + 10. Death NO DEFINITE SYMPTOMS + 11. (Mortality probably 2. Beginning epilation. + 12. 100%) + 13. + 14. + 15. + 16. + 17. + 18. 3. Loss of appetite + 19. and general malaise. 1. Epilation + 20. 4. Fever. 2. Loss of appetite + 21. 5. Severe inflammation and malaise. + 22. of the mouth and throat 3. Sore throat. + 23. 4. Pallor. + 24. 5. Petechiae + 25. 6. Diarrhea + 26. 7. Moderate emacia- + 27. 6. Pallor. tion. + 28. 7. Petechiae, diarrhea + 29. and nose bleeds (Recovery unless com- + 30. plicated by previous + 31. 8. Rapid emaciation poor health or + Death super-imposed in- + (Mortality probably 50%) juries or infec- + tion). + +It was concluded that persons exposed to the bombs at the time of +detonation did show effects from ionizing radiation and that some of +these patients, otherwise uninjured, died. Deaths from radiation began +about a week after exposure and reached a peak in 3 to 4 weeks. They +practically ceased to occur after 7 to 8 weeks. + +Treatment of the burns and other physical injuries was carried out by +the Japanese by orthodox methods. Treatment of radiation effects by +them included general supportative measures such as rest and high +vitamin and caloric diets. Liver and calcium preparations were +administered by injection and blood transfusions were used to combat +hemorrhage. Special vitamin preparations and other special drugs used +in the treatment of similar medical conditions were used by American +Army Medical Corps officers after their arrival. Although the general +measures instituted were of some benefit no definite effect of any of +the specific measures on the course of the disease could be +demonstrated. The use of sulfonamide drugs by the Japanese and +particularly of penicillin by the American physicians after their +arrival undoubtedly helped control the infections and they appear to be +the single important type of treatment which may have effectively +altered the earlier course of these patients. + +One of the most important tasks assigned to the mission which +investigated the effects of the bombing was that of determining if the +radiation effects were all due to the instantaneous discharges at the +time of the explosion, or if people were being harmed in addition from +persistent radioactivity. This question was investigated from two +points of view. Direct measurements of persistent radioactivity were +made at the time of the investigation. From these measurements, +calculations were made of the graded radiation dosages, i.e., the total +amount of radiation which could have been absorbed by any person. +These calculations showed that the highest dosage which would have been +received from persistent radioactivity at Hiroshima was between 6 and +25 roentgens of gamma radiation; the highest in the Nagasaki Area was +between 30 and 110 roentgens of gamma radiation. The latter figure +does not refer to the city itself, but to a localized area in the +Nishiyama District. In interpreting these findings it must be +understood that to get these dosages, one would have had to remain at +the point of highest radioactivity for 6 weeks continuously, from the +first hour after the bombing. It is apparent therefore that insofar as +could be determined at Hiroshima and Nagasaki, the residual radiation +alone could not have been detrimental to the health of persons entering +and living in the bombed areas after the explosion. + +The second approach to this question was to determine if any persons +not in the city at the time of the explosion, but coming in immediately +afterwards exhibited any symptoms or findings which might have been due +to persistence induced radioactivity. By the time of the arrival of +the Manhattan Engineer District group, several Japanese studies had +been done on such persons. None of the persons examined in any of +these studies showed any symptoms which could be attributed to +radiation, and their actual blood cell counts were consistently within +the normal range. Throughout the period of the Manhattan Engineer +District investigation, Japanese doctors and patients were repeatedly +requested to bring to them any patients who they thought might be +examples of persons harmed from persistent radioactivity. No such +subjects were found. + +It was concluded therefore as a result of these findings and lack of +findings, that although a measurable quantity of induced radioactivity +was found, it had not been sufficient to cause any harm to persons +living in the two cities after the bombings. + + + +SHIELDING FROM RADIATION + +Exact figures on the thicknesses of various substances to provide +complete or partial protection from the effects of radiation in +relation to the distance from the center of explosion, cannot be +released at this time. Studies of collected data are still under way. +It can be stated, however, that at a reasonable distance, say about 1/2 +mile from the center of explosion, protection to persons from radiation +injury can be afforded by a layer of concrete or other material whose +thickness does not preclude reasonable construction. + +Radiation ultimately caused the death of the few persons not killed by +other effects and who were fully exposed to the bombs up to a distance +of about 1/2 mile from X. The British Mission has estimated that +people in the open had a 50% chance of surviving the effects of +radiation at 3/4 of a mile from X. + + + +EFFECTS OF THE ATOMIC BOMBINGS ON THE INHABITANTS OF THE BOMBED CITIES + +In both Hiroshima and Nagasaki the tremendous scale of the disaster +largely destroyed the cities as entities. Even the worst of all other +previous bombing attacks on Germany and Japan, such as the incendiary +raids on Hamburg in 1943 and on Tokyo in 1945, were not comparable to +the paralyzing effect of the atomic bombs. In addition to the huge +number of persons who were killed or injuried so that their services in +rehabilitation were not available, a panic flight of the population +took place from both cities immediately following the atomic +explosions. No significant reconstruction or repair work was +accomplished because of the slow return of the population; at the end +of November 1945 each of the cities had only about 140,000 people. +Although the ending of the war almost immediately after the atomic +bombings removed much of the incentive of the Japanese people toward +immediate reconstruction of their losses, their paralysis was still +remarkable. Even the clearance of wreckage and the burning of the many +bodies trapped in it were not well organized some weeks after the +bombings. As the British Mission has stated, "the impression which +both cities make is of having sunk, in an instant and without a +struggle, to the most primitive level." + +Aside from physical injury and damage, the most significant effect of +the atomic bombs was the sheer terror which it struck into the peoples +of the bombed cities. This terror, resulting in immediate hysterical +activity and flight from the cities, had one especially pronounced +effect: persons who had become accustomed to mass air raids had grown +to pay little heed to single planes or small groups of planes, but +after the atomic bombings the appearance of a single plane caused more +terror and disruption of normal life than the appearance of many +hundreds of planes had ever been able to cause before. The effect of +this terrible fear of the potential danger from even a single enemy +plane on the lives of the peoples of the world in the event of any +future war can easily be conjectured. + +The atomic bomb did not alone win the war against Japan, but it most +certainly ended it, saving the thousands of Allied lives that would +have been lost in any combat invasion of Japan. + + + +EYEWITNESS ACCOUNT + Hiroshima--August 6th, 1945 + +by Father John A. Siemes, professor of modern philosphy at Tokyo's +Catholic University + + +Up to August 6th, occasional bombs, which did no great damage, had +fallen on Hiroshima. Many cities roundabout, one after the other, were +destroyed, but Hiroshima itself remained protected. There were almost +daily observation planes over the city but none of them dropped a bomb. +The citizens wondered why they alone had remained undisturbed for so +long a time. There were fantastic rumors that the enemy had something +special in mind for this city, but no one dreamed that the end would +come in such a fashion as on the morning of August 6th. + +August 6th began in a bright, clear, summer morning. About seven +o'clock, there was an air raid alarm which we had heard almost every +day and a few planes appeared over the city. No one paid any attention +and at about eight o'clock, the all-clear was sounded. I am sitting in +my room at the Novitiate of the Society of Jesus in Nagatsuke; during +the past half year, the philosophical and theological section of our +Mission had been evacuated to this place from Tokyo. The Novitiate is +situated approximately two kilometers from Hiroshima, half-way up the +sides of a broad valley which stretches from the town at sea level into +this mountainous hinterland, and through which courses a river. From +my window, I have a wonderful view down the valley to the edge of the +city. + +Suddenly--the time is approximately 8:14--the whole valley is filled by +a garish light which resembles the magnesium light used in photography, +and I am conscious of a wave of heat. I jump to the window to find out +the cause of this remarkable phenomenon, but I see nothing more than +that brilliant yellow light. As I make for the door, it doesn't occur +to me that the light might have something to do with enemy planes. On +the way from the window, I hear a moderately loud explosion which seems +to come from a distance and, at the same time, the windows are broken +in with a loud crash. There has been an interval of perhaps ten +seconds since the flash of light. I am sprayed by fragments of glass. +The entire window frame has been forced into the room. I realize now +that a bomb has burst and I am under the impression that it exploded +directly over our house or in the immediate vicinity. + +I am bleeding from cuts about the hands and head. I attempt to get out +of the door. It has been forced outwards by the air pressure and has +become jammed. I force an opening in the door by means of repeated +blows with my hands and feet and come to a broad hallway from which +open the various rooms. Everything is in a state of confusion. All +windows are broken and all the doors are forced inwards. The +bookshelves in the hallway have tumbled down. I do not note a second +explosion and the fliers seem to have gone on. Most of my colleagues +have been injured by fragments of glass. A few are bleeding but none +has been seriously injured. All of us have been fortunate since it is +now apparent that the wall of my room opposite the window has been +lacerated by long fragments of glass. + +We proceed to the front of the house to see where the bomb has landed. +There is no evidence, however, of a bomb crater; but the southeast +section of the house is very severely damaged. Not a door nor a window +remains. The blast of air had penetrated the entire house from the +southeast, but the house still stands. It is constructed in a Japanese +style with a wooden framework, but has been greatly strengthened by the +labor of our Brother Gropper as is frequently done in Japanese homes. +Only along the front of the chapel which adjoins the house, three +supports have given way (it has been made in the manner of Japanese +temple, entirely out of wood.) + +Down in the valley, perhaps one kilometer toward the city from us, +several peasant homes are on fire and the woods on the opposite side of +the valley are aflame. A few of us go over to help control the flames. +While we are attempting to put things in order, a storm comes up and it +begins to rain. Over the city, clouds of smoke are rising and I hear a +few slight explosions. I come to the conclusion that an incendiary +bomb with an especially strong explosive action has gone off down in +the valley. A few of us saw three planes at great altitude over the +city at the time of the explosion. I, myself, saw no aircraft +whatsoever. + +Perhaps a half-hour after the explosion, a procession of people begins +to stream up the valley from the city. The crowd thickens +continuously. A few come up the road to our house. We give them first +aid and bring them into the chapel, which we have in the meantime +cleaned and cleared of wreckage, and put them to rest on the straw mats +which constitute the floor of Japanese houses. A few display horrible +wounds of the extremities and back. The small quantity of fat which we +possessed during this time of war was soon used up in the care of the +burns. Father Rektor who, before taking holy orders, had studied +medicine, ministers to the injured, but our bandages and drugs are soon +gone. We must be content with cleansing the wounds. + +More and more of the injured come to us. The least injured drag the +more seriously wounded. There are wounded soldiers, and mothers +carrying burned children in their arms. From the houses of the farmers +in the valley comes word: "Our houses are full of wounded and dying. +Can you help, at least by taking the worst cases?" The wounded come +from the sections at the edge of the city. They saw the bright light, +their houses collapsed and buried the inmates in their rooms. Those +that were in the open suffered instantaneous burns, particularly on the +lightly clothed or unclothed parts of the body. Numerous fires sprang +up which soon consumed the entire district. We now conclude that the +epicenter of the explosion was at the edge of the city near the +Jokogawa Station, three kilometers away from us. We are concerned +about Father Kopp who that same morning, went to hold Mass at the +Sisters of the Poor, who have a home for children at the edge of the +city. He had not returned as yet. + +Toward noon, our large chapel and library are filled with the seriously +injured. The procession of refugees from the city continues. Finally, +about one o'clock, Father Kopp returns, together with the Sisters. +Their house and the entire district where they live has burned to the +ground. Father Kopp is bleeding about the head and neck, and he has a +large burn on the right palm. He was standing in front of the nunnery +ready to go home. All of a sudden, he became aware of the light, felt +the wave of heat and a large blister formed on his hand. The windows +were torn out by the blast. He thought that the bomb had fallen in his +immediate vicinity. The nunnery, also a wooden structure made by our +Brother Gropper, still remained but soon it is noted that the house is +as good as lost because the fire, which had begun at many points in the +neighborhood, sweeps closer and closer, and water is not available. +There is still time to rescue certain things from the house and to bury +them in an open spot. Then the house is swept by flame, and they fight +their way back to us along the shore of the river and through the +burning streets. + +Soon comes news that the entire city has been destroyed by the +explosion and that it is on fire. What became of Father Superior and +the three other Fathers who were at the center of the city at the +Central Mission and Parish House? We had up to this time not given +them a thought because we did not believe that the effects of the bomb +encompassed the entire city. Also, we did not want to go into town +except under pressure of dire necessity, because we thought that the +population was greatly perturbed and that it might take revenge on any +foreigners which they might consider spiteful onlookers of their +misfortune, or even spies. + +Father Stolte and Father Erlinghagen go down to the road which is still +full of refugees and bring in the seriously injured who have sunken by +the wayside, to the temporary aid station at the village school. There +iodine is applied to the wounds but they are left uncleansed. Neither +ointments nor other therapeutic agents are available. Those that have +been brought in are laid on the floor and no one can give them any +further care. What could one do when all means are lacking? Under +those circumstances, it is almost useless to bring them in. Among the +passersby, there are many who are uninjured. In a purposeless, +insensate manner, distraught by the magnitude of the disaster most of +them rush by and none conceives the thought of organizing help on his +own initiative. They are concerned only with the welfare of their own +families. It became clear to us during these days that the Japanese +displayed little initiative, preparedness, and organizational skill in +preparation for catastrophes. They failed to carry out any rescue work +when something could have been saved by a cooperative effort, and +fatalistically let the catastrophe take its course. When we urged them +to take part in the rescue work, they did everything willingly, but on +their own initiative they did very little. + +At about four o'clock in the afternoon, a theology student and two +kindergarten children, who lived at the Parish House and adjoining +buildings which had burned down, came in and said that Father Superior +LaSalle and Father Schiffer had been seriously injured and that they +had taken refuge in Asano Park on the river bank. It is obvious that +we must bring them in since they are too weak to come here on foot. + +Hurriedly, we get together two stretchers and seven of us rush toward +the city. Father Rektor comes along with food and medicine. The +closer we get to the city, the greater is the evidence of destruction +and the more difficult it is to make our way. The houses at the edge +of the city are all severely damaged. Many have collapsed or burned +down. Further in, almost all of the dwellings have been damaged by +fire. Where the city stood, there is a gigantic burned-out scar. We +make our way along the street on the river bank among the burning and +smoking ruins. Twice we are forced into the river itself by the heat +and smoke at the level of the street. + +Frightfully burned people beckon to us. Along the way, there are many +dead and dying. On the Misasi Bridge, which leads into the inner city +we are met by a long procession of soldiers who have suffered burns. +They drag themselves along with the help of staves or are carried by +their less severely injured comrades...an endless procession of the +unfortunate. + +Abandoned on the bridge, there stand with sunken heads a number of +horses with large burns on their flanks. On the far side, the cement +structure of the local hospital is the only building that remains +standing. Its interior, however, has been burned out. It acts as a +landmark to guide us on our way. + +Finally we reach the entrance of the park. A large proportion of the +populace has taken refuge there, but even the trees of the park are on +fire in several places. Paths and bridges are blocked by the trunks of +fallen trees and are almost impassable. We are told that a high wind, +which may well have resulted from the heat of the burning city, has +uprooted the large trees. It is now quite dark. Only the fires, which +are still raging in some places at a distance, give out a little light. + +At the far corner of the park, on the river bank itself, we at last +come upon our colleagues. Father Schiffer is on the ground pale as a +ghost. He has a deep incised wound behind the ear and has lost so much +blood that we are concerned about his chances for survival. The Father +Superior has suffered a deep wound of the lower leg. Father Cieslik +and Father Kleinsorge have minor injuries but are completely exhausted. + + +While they are eating the food that we have brought along, they tell us +of their experiences. They were in their rooms at the Parish House--it +was a quarter after eight, exactly the time when we had heard the +explosion in Nagatsuke--when came the intense light and immediately +thereafter the sound of breaking windows, walls and furniture. They +were showered with glass splinters and fragments of wreckage. Father +Schiffer was buried beneath a portion of a wall and suffered a severe +head injury. The Father Superior received most of the splinters in his +back and lower extremity from which he bled copiously. Everything was +thrown about in the rooms themselves, but the wooden framework of the +house remained intact. The solidity of the structure which was the +work of Brother Gropper again shone forth. + +They had the same impression that we had in Nagatsuke: that the bomb +had burst in their immediate vicinity. The Church, school, and all +buildings in the immediate vicinity collapsed at once. Beneath the +ruins of the school, the children cried for help. They were freed with +great effort. Several others were also rescued from the ruins of +nearby dwellings. Even the Father Superior and Father Schiffer despite +their wounds, rendered aid to others and lost a great deal of blood in +the process. + +In the meantime, fires which had begun some distance away are raging +even closer, so that it becomes obvious that everything would soon burn +down. Several objects are rescued from the Parish House and were +buried in a clearing in front of the Church, but certain valuables and +necessities which had been kept ready in case of fire could not be +found on account of the confusion which had been wrought. It is high +time to flee, since the oncoming flames leave almost no way open. +Fukai, the secretary of the Mission, is completely out of his mind. He +does not want to leave the house and explains that he does not want to +survive the destruction of his fatherland. He is completely uninjured. +Father Kleinsorge drags him out of the house on his back and he is +forcefully carried away. + + +Beneath the wreckage of the houses along the way, many have been +trapped and they scream to be rescued from the oncoming flames. They +must be left to their fate. The way to the place in the city to which +one desires to flee is no longer open and one must make for Asano Park. +Fukai does not want to go further and remains behind. He has not been +heard from since. In the park, we take refuge on the bank of the +river. A very violent whirlwind now begins to uproot large trees, and +lifts them high into the air. As it reaches the water, a waterspout +forms which is approximately 100 meters high. The violence of the +storm luckily passes us by. Some distance away, however, where +numerous refugees have taken shelter, many are blown into the river. +Almost all who are in the vicinity have been injured and have lost +relatives who have been pinned under the wreckage or who have been lost +sight of during the flight. There is no help for the wounded and some +die. No one pays any attention to a dead man lying nearby. + +The transportation of our own wounded is difficult. It is not possible +to dress their wounds properly in the darkness, and they bleed again +upon slight motion. As we carry them on the shaky litters in the dark +over fallen trees of the park, they suffer unbearable pain as the +result of the movement, and lose dangerously large quantities of blood. +Our rescuing angel in this difficult situation is a Japanese Protestant +pastor. He has brought up a boat and offers to take our wounded up +stream to a place where progress is easier. First, we lower the litter +containing Father Schiffer into the boat and two of us accompany him. +We plan to bring the boat back for the Father Superior. The boat +returns about one-half hour later and the pastor requests that several +of us help in the rescue of two children whom he had seen in the river. +We rescue them. They have severe burns. Soon they suffer chills and +die in the park. + +The Father Superior is conveyed in the boat in the same manner as +Father Schiffer. The theology student and myself accompany him. +Father Cieslik considers himself strong enough to make his way on foot +to Nagatsuke with the rest of us, but Father Kleinsorge cannot walk so +far and we leave him behind and promise to come for him and the +housekeeper tomorrow. From the other side of the stream comes the +whinny of horses who are threatened by the fire. We land on a sand +spit which juts out from the shore. It is full of wounded who have +taken refuge there. They scream for aid for they are afraid of +drowning as the river may rise with the sea, and cover the sand spit. +They themselves are too weak to move. However, we must press on and +finally we reach the spot where the group containing Father Schiffer is +waiting. + + +Here a rescue party had brought a large case of fresh rice cakes but +there is no one to distribute them to the numerous wounded that lie all +about. We distribute them to those that are nearby and also help +ourselves. The wounded call for water and we come to the aid of a few. +Cries for help are heard from a distance, but we cannot approach the +ruins from which they come. A group of soldiers comes along the road +and their officer notices that we speak a strange language. He at once +draws his sword, screamingly demands who we are and threatens to cut us +down. Father Laures, Jr., seizes his arm and explains that we are +German. We finally quiet him down. He thought that we might well be +Americans who had parachuted down. Rumors of parachutists were being +bandied about the city. The Father Superior who was clothed only in a +shirt and trousers, complains of feeling freezing cold, despite the +warm summer night and the heat of the burning city. The one man among +us who possesses a coat gives it to him and, in addition, I give him my +own shirt. To me, it seems more comfortable to be without a shirt in +the heat. + +In the meantime, it has become midnight. Since there are not enough of +us to man both litters with four strong bearers, we determine to remove +Father Schiffer first to the outskirts of the city. From there, +another group of bearers is to take over to Nagatsuke; the others are +to turn back in order to rescue the Father Superior. I am one of the +bearers. The theology student goes in front to warn us of the numerous +wires, beams and fragments of ruins which block the way and which are +impossible to see in the dark. Despite all precautions, our progress +is stumbling and our feet get tangled in the wire. Father Kruer falls +and carries the litter with him. Father Schiffer becomes half +unconscious from the fall and vomits. We pass an injured man who sits +all alone among the hot ruins and whom I had seen previously on the way +down. + +On the Misasa Bridge, we meet Father Tappe and Father Luhmer, who have +come to meet us from Nagatsuke. They had dug a family out of the ruins +of their collapsed house some fifty meters off the road. The father of +the family was already dead. They had dragged out two girls and placed +them by the side of the road. Their mother was still trapped under +some beams. They had planned to complete the rescue and then to press +on to meet us. At the outskirts of the city, we put down the litter +and leave two men to wait until those who are to come from Nagatsuke +appear. The rest of us turn back to fetch the Father Superior. + +Most of the ruins have now burned down. The darkness kindly hides the +many forms that lie on the ground. Only occasionally in our quick +progress do we hear calls for help. One of us remarks that the +remarkable burned smell reminds him of incinerated corpses. The +upright, squatting form which we had passed by previously is still +there. + +Transportation on the litter, which has been constructed out of boards, +must be very painful to the Father Superior, whose entire back is full +of fragments of glass. In a narrow passage at the edge of town, a car +forces us to the edge of the road. The litter bearers on the left side +fall into a two meter deep ditch which they could not see in the +darkness. Father Superior hides his pain with a dry joke, but the +litter which is now no longer in one piece cannot be carried further. +We decide to wait until Kinjo can bring a hand cart from Nagatsuke. He +soon comes back with one that he has requisitioned from a collapsed +house. We place Father Superior on the cart and wheel him the rest of +the way, avoiding as much as possible the deeper pits in the road. + +About half past four in the morning, we finally arrive at the +Novitiate. Our rescue expedition had taken almost twelve hours. +Normally, one could go back and forth to the city in two hours. Our +two wounded were now, for the first time, properly dressed. I get two +hours sleep on the floor; some one else has taken my own bed. Then I +read a Mass in gratiarum actionem, it is the 7th of August, the +anniversary of the foundation of our society. Then we bestir ourselves +to bring Father Kleinsorge and other acquaintances out of the city. + + +We take off again with the hand cart. The bright day now reveals the +frightful picture which last night's darkness had partly concealed. +Where the city stood everything, as far as the eye could reach, is a +waste of ashes and ruin. Only several skeletons of buildings +completely burned out in the interior remain. The banks of the river +are covered with dead and wounded, and the rising waters have here and +there covered some of the corpses. On the broad street in the +Hakushima district, naked burned cadavers are particularly numerous. +Among them are the wounded who are still alive. A few have crawled +under the burnt-out autos and trams. Frightfully injured forms beckon +to us and then collapse. An old woman and a girl whom she is pulling +along with her fall down at our feet. We place them on our cart and +wheel them to the hospital at whose entrance a dressing station has +been set up. Here the wounded lie on the hard floor, row on row. Only +the largest wounds are dressed. We convey another soldier and an old +woman to the place but we cannot move everybody who lies exposed in the +sun. It would be endless and it is questionable whether those whom we +can drag to the dressing station can come out alive, because even here +nothing really effective can be done. Later, we ascertain that the +wounded lay for days in the burnt-out hallways of the hospital and +there they died. + +We must proceed to our goal in the park and are forced to leave the +wounded to their fate. We make our way to the place where our church +stood to dig up those few belongings that we had buried yesterday. We +find them intact. Everything else has been completely burned. In the +ruins, we find a few molten remnants of holy vessels. At the park, we +load the housekeeper and a mother with her two children on the cart. +Father Kleinsorge feels strong enough, with the aid of Brother +Nobuhara, to make his way home on foot. The way back takes us once +again past the dead and wounded in Hakushima. Again no rescue parties +are in evidence. At the Misasa Bridge, there still lies the family +which the Fathers Tappe and Luhmer had yesterday rescued from the +ruins. A piece of tin had been placed over them to shield them from +the sun. We cannot take them along for our cart is full. We give them +and those nearby water to drink and decide to rescue them later. At +three o'clock in the afternoon, we are back in Nagatsuka. + +After we have had a few swallows and a little food, Fathers Stolte, +Luhmer, Erlinghagen and myself, take off once again to bring in the +family. Father Kleinsorge requests that we also rescue two children +who had lost their mother and who had lain near him in the park. On +the way, we were greeted by strangers who had noted that we were on a +mission of mercy and who praised our efforts. We now met groups of +individuals who were carrying the wounded about on litters. As we +arrived at the Misasa Bridge, the family that had been there was gone. +They might well have been borne away in the meantime. There was a +group of soldiers at work taking away those that had been sacrificed +yesterday. + + +More than thirty hours had gone by until the first official rescue +party had appeared on the scene. We find both children and take them +out of the park: a six-year old boy who was uninjured, and a +twelve-year old girl who had been burned about the head, hands and +legs, and who had lain for thirty hours without care in the park. The +left side of her face and the left eye were completely covered with +blood and pus, so that we thought that she had lost the eye. When the +wound was later washed, we noted that the eye was intact and that the +lids had just become stuck together. On the way home, we took another +group of three refugees with us. They first wanted to know, however, +of what nationality we were. They, too, feared that we might be +Americans who had parachuted in. When we arrived in Nagatsuka, it had +just become dark. + +We took under our care fifty refugees who had lost everything. The +majority of them were wounded and not a few had dangerous burns. +Father Rektor treated the wounds as well as he could with the few +medicaments that we could, with effort, gather up. He had to confine +himself in general to cleansing the wounds of purulent material. Even +those with the smaller burns are very weak and all suffered from +diarrhea. In the farm houses in the vicinity, almost everywhere, there +are also wounded. Father Rektor made daily rounds and acted in the +capacity of a painstaking physician and was a great Samaritan. Our +work was, in the eyes of the people, a greater boost for Christianity +than all our work during the preceding long years. + +Three of the severely burned in our house died within the next few +days. Suddenly the pulse and respirations ceased. It is certainly a +sign of our good care that so few died. In the official aid stations +and hospitals, a good third or half of those that had been brought in +died. They lay about there almost without care, and a very high +percentage succumbed. Everything was lacking: doctors, assistants, +dressings, drugs, etc. In an aid station at a school at a nearby +village, a group of soldiers for several days did nothing except to +bring in and cremate the dead behind the school. + + +During the next few days, funeral processions passed our house from +morning to night, bringing the deceased to a small valley nearby. +There, in six places, the dead were burned. People brought their own +wood and themselves did the cremation. Father Luhmer and Father Laures +found a dead man in a nearby house who had already become bloated and +who emitted a frightful odor. They brought him to this valley and +incinerated him themselves. Even late at night, the little valley was +lit up by the funeral pyres. + +We made systematic efforts to trace our acquaintances and the families +of the refugees whom we had sheltered. Frequently, after the passage +of several weeks, some one was found in a distant village or hospital +but of many there was no news, and these were apparently dead. We were +lucky to discover the mother of the two children whom we had found in +the park and who had been given up for dead. After three weeks, she +saw her children once again. In the great joy of the reunion were +mingled the tears for those whom we shall not see again. + + +The magnitude of the disaster that befell Hiroshima on August 6th was +only slowly pieced together in my mind. I lived through the +catastrophe and saw it only in flashes, which only gradually were +merged to give me a total picture. What actually happened +simultaneously in the city as a whole is as follows: As a result of the +explosion of the bomb at 8:15, almost the entire city was destroyed at +a single blow. Only small outlying districts in the southern and +eastern parts of the town escaped complete destruction. The bomb +exploded over the center of the city. As a result of the blast, the +small Japanese houses in a diameter of five kilometers, which +compressed 99% of the city, collapsed or were blown up. Those who were +in the houses were buried in the ruins. Those who were in the open +sustained burns resulting from contact with the substance or rays +emitted by the bomb. Where the substance struck in quantity, fires +sprang up. These spread rapidly. + +The heat which rose from the center created a whirlwind which was +effective in spreading fire throughout the whole city. Those who had +been caught beneath the ruins and who could not be freed rapidly, and +those who had been caught by the flames, became casualties. As much as +six kilometers from the center of the explosion, all houses were +damaged and many collapsed and caught fire. Even fifteen kilometers +away, windows were broken. It was rumored that the enemy fliers had +spread an explosive and incendiary material over the city and then had +created the explosion and ignition. A few maintained that they saw the +planes drop a parachute which had carried something that exploded at a +height of 1,000 meters. The newspapers called the bomb an "atomic +bomb" and noted that the force of the blast had resulted from the +explosion of uranium atoms, and that gamma rays had been sent out as a +result of this, but no one knew anything for certain concerning the +nature of the bomb. + +How many people were a sacrifice to this bomb? Those who had lived +through the catastrophe placed the number of dead at at least 100,000. +Hiroshima had a population of 400,000. Official statistics place the +number who had died at 70,000 up to September 1st, not counting the +missing ... and 130,000 wounded, among them 43,500 severely wounded. +Estimates made by ourselves on the basis of groups known to us show +that the number of 100,000 dead is not too high. Near us there are two +barracks, in each of which forty Korean workers lived. On the day of +the explosion, they were laboring on the streets of Hiroshima. Four +returned alive to one barracks and sixteen to the other. 600 students +of the Protestant girls' school worked in a factory, from which only +thirty to forty returned. Most of the peasant families in the +neighborhood lost one or more of their members who had worked at +factories in the city. Our next door neighbor, Tamura, lost two +children and himself suffered a large wound since, as it happened, he +had been in the city on that day. The family of our reader suffered +two dead, father and son; thus a family of five members suffered at +least two losses, counting only the dead and severely wounded. There +died the Mayor, the President of the central Japan district, the +Commander of the city, a Korean prince who had been stationed in +Hiroshima in the capacity of an officer, and many other high ranking +officers. Of the professors of the University, thirty-two were killed +or severely injured. Especially hard hit were the soldiers. The +Pioneer Regiment was almost entirely wiped out. The barracks were near +the center of the explosion. + +Thousands of wounded who died later could doubtless have been rescued +had they received proper treatment and care, but rescue work in a +catastrophe of this magnitude had not been envisioned; since the whole +city had been knocked out at a blow, everything which had been prepared +for emergency work was lost, and no preparation had been made for +rescue work in the outlying districts. Many of the wounded also died +because they had been weakened by under-nourishment and consequently +lacked in strength to recover. Those who had their normal strength and +who received good care slowly healed the burns which had been +occasioned by the bomb. There were also cases, however, whose +prognosis seemed good who died suddenly. There were also some who had +only small external wounds who died within a week or later, after an +inflammation of the pharynx and oral cavity had taken place. We +thought at first that this was the result of inhalation of the +substance of the bomb. Later, a commission established the thesis that +gamma rays had been given out at the time of the explosion, following +which the internal organs had been injured in a manner resembling that +consequent upon Roentgen irradiation. This produces a diminution in +the numbers of the white corpuscles. + +Only several cases are known to me personally where individuals who did +not have external burns later died. Father Kleinsorge and Father +Cieslik, who were near the center of the explosion, but who did not +suffer burns became quite weak some fourteen days after the explosion. +Up to this time small incised wounds had healed normally, but +thereafter the wounds which were still unhealed became worse and are to +date (in September) still incompletely healed. The attending physician +diagnosed it as leucopania. There thus seems to be some truth in the +statement that the radiation had some effect on the blood. I am of the +opinion, however, that their generally undernourished and weakened +condition was partly responsible for these findings. It was noised +about that the ruins of the city emitted deadly rays and that workers +who went there to aid in the clearing died, and that the central +district would be uninhabitable for some time to come. I have my +doubts as to whether such talk is true and myself and others who worked +in the ruined area for some hours shortly after the explosion suffered +no such ill effects. + +None of us in those days heard a single outburst against the Americans +on the part of the Japanese, nor was there any evidence of a vengeful +spirit. The Japanese suffered this terrible blow as part of the +fortunes of war ... something to be borne without complaint. During +this, war, I have noted relatively little hatred toward the allies on +the part of the people themselves, although the press has taken +occasion to stir up such feelings. After the victories at the +beginning of the war, the enemy was rather looked down upon, but when +allied offensive gathered momentum and especially after the advent of +the majestic B-29's, the technical skill of America became an object of +wonder and admiration. + +The following anecdote indicates the spirit of the Japanese: A few days +after the atomic bombing, the secretary of the University came to us +asserting that the Japanese were ready to destroy San Francisco by +means of an equally effective bomb. It is dubious that he himself +believed what he told us. He merely wanted to impress upon us +foreigners that the Japanese were capable of similar discoveries. In +his nationalistic pride, he talked himself into believing this. The +Japanese also intimated that the principle of the new bomb was a +Japanese discovery. It was only lack of raw materials, they said, +which prevented its construction. In the meantime, the Germans were +said to have carried the discovery to a further stage and were about to +initiate such bombing. The Americans were reputed to have learned the +secret from the Germans, and they had then brought the bomb to a stage +of industrial completion. + + +We have discussed among ourselves the ethics of the use of the bomb. +Some consider it in the same category as poison gas and were against +its use on a civil population. Others were of the view that in total +war, as carried on in Japan, there was no difference between civilians +and soldiers, and that the bomb itself was an effective force tending +to end the bloodshed, warning Japan to surrender and thus to avoid +total destruction. It seems logical to me that he who supports total +war in principle cannot complain of war against civilians. The crux of +the matter is whether total war in its present form is justifiable, +even when it serves a just purpose. Does it not have material and +spiritual evil as its consequences which far exceed whatever good that +might result? 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For an HTML +version of this document and additional public domain documents +on nuclear history, visit Trinity Atomic Web Site: +http://www.envirolink.org/issues/nuketesting/ + + + + + +THE ATOMIC BOMBINGS OF HIROSHIMA AND NAGASAKI + +by The Manhattan Engineer District, June 29, 1946. + + + +Index + + + FOREWORD + INTRODUCTION + THE MANHATTAN PROJECT INVESTIGATING GROUP + PROPAGANDA + SUMMARY OF DAMAGES AND INJURIES + MAIN CONCLUSIONS + THE SELECTION OF THE TARGET + DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS + Hiroshima + Nagasaki + THE ATTACKS + Hiroshima + Nagasaki + GENERAL COMPARISON OF HIROSHIMA AND NAGASAKI + GENERAL DESCRIPTION OF DAMAGE CAUSED BY THE ATOMIC EXPLOSIONS + TOTAL CASUALTIES + THE NATURE OF AN ATOMIC EXPLOSION + CHARACTERISTICS OF THE DAMAGE CAUSED BY THE ATOMIC BOMBS + CALCULATIONS OF THE PEAK PRESSURE OF THE BLAST WAVE + LONG RANGE BLAST DAMAGE + GROUND SHOCK + SHIELDING, OR SCREENING, FROM THE BLAST + FLASH BURN + CHARACTERISTICS OF INJURIES TO PERSONS + BURNS + MECHANICAL INJURIES + BLAST INJURIES + RADIATION INJURIES + SHIELDING FROM RADIATION + EFFECTS OF THE ATOMIC BOMBINGS ON THE INHABITANTS OF THE CITIES + APPENDIX: Father Siemes' eyewitness account + + + +FOREWORD + + +This report describes the effects of the atomic bombs which were dropped on +the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, +respectively. It summarizes all the authentic information that is +available on damage to structures, injuries to personnel, morale effect, +etc., which can be released at this time without prejudicing the security +of the United States. + +This report has been compiled by the Manhattan Engineer District of the +United States Army under the direction of Major General Leslie R. Groves. +Special acknowledgement to those whose work contributed largely to this +report is made to: + + The Special Manhattan Engineer District Investigating Group, + The United States Strategic Bombing Survey, + The British Mission to Japan, and + +The Joint Atomic Bomb Investigating Group (Medical). and particularly to +the following individuals: + +Col. Stafford L. Warren, Medical Corps, United States Army, for his +evaluation of medical data, + +Capt. Henry L. Barnett, Medical Corps, United States Army, for his +evaluation of medical data, + +Dr. R. Serber, for his comments on flash burn, + +Dr. Hans Bethe, Cornell University, for his information of the nature of +atomic explosions, + +Majors Noland Varley and Walter C. Youngs, Corps of Engineers, United +States Army, for their evaluation of physical damage to structures, + +J. 0. Hirschfelder, J. L. Magee, M. Hull, and S. T. Cohen, of the Los +Alamos Laboratory, for their data on nuclear explosions, + +Lieut. Col. David B. Parker, Corps of Engineers, United States Army, for +editing this report. + + + +INTRODUCTION + + +Statement by the President of the United States: "Sixteen hours ago an +American airplane dropped one bomb on Hiroshima, Japan, and destroyed its +usefulness to the enemy. That bomb had more power than 20,000 tons of +T.N.T. It had more than two thousand times the blast power of the British +Grand Slam, which is the largest bomb ever yet used in the history of +warfare". + +These fateful words of the President on August 6th, 1945, marked the first +public announcement of the greatest scientific achievement in history. The +atomic bomb, first tested in New Mexico on July 16, 1945, had just been +used against a military target. + +On August 6th, 1945, at 8:15 A.M., Japanese time, a B-29 heavy bomber +flying at high altitude dropped the first atomic bomb on Hiroshima. More +than 4 square miles of the city were instantly and completely devastated. +66,000 people were killed, and 69,000 injured. + +On August 9th, three days later, at 11:02 A.M., another B-29 dropped the +second bomb on the industrial section of the city of Nagasaki, totally +destroying 1 1/2 square miles of the city, killing 39,000 persons, and +injuring 25,000 more. + +On August 10, the day after the atomic bombing of Nagasaki, the Japanese +government requested that it be permitted to surrender under the terms of +the Potsdam declaration of July 26th which it had previously ignored. + + + +THE MANHATTAN PROJECT ATOMIC BOMB INVESTIGATING GROUP + + +On August 11th, 1945, two days after the bombing of Nagasaki, a message was +dispatched from Major General Leslie R. Groves to Brigadier General Thomas +F. Farrell, who was his deputy in atomic bomb work and was representing him +in operations in the Pacific, directing him to organize a special Manhattan +Project Atomic Bomb Investigating Group. + +This Group was to secure scientific, technical and medical intelligence in +the atomic bomb field from within Japan as soon as possible after the +cessation of hostilities. The mission was to consist of three groups: + + 1. Group for Hiroshima. + 2. Group for Nagasaki. + 3. Group to secure information concerning general Japanese activities in +the field of atomic bombs. + +The first two groups were organized to accompany the first American troops +into Hiroshima and Nagasaki. + +The primary purposes of the mission were as follows, in order of +importance: + +1. To make certain that no unusual hazards were present in the bombed +cities. + +2. To secure all possible information concerning the effects of the bombs, +both usual and unusual, and particularly with regard to radioactive +effects, if any, on the targets or elsewhere. + +General Groves further stated that all available specialist personnel and +instruments would be sent from the United States, and that the Supreme +Allied Commander in the Pacific would be informed about the organization of +the mission. + +On the same day, 11 August, the special personnel who formed the part of +the investigating group to be sent from the United States were selected and +ordered to California with instructions to proceed overseas at once to +accomplish the purposes set forth in the message to General Farrell. The +main party departed from Hamilton Field, California on the morning of 13 +August and arrived in the Marianas on 15 August. + +On 12 August the Chief of Staff sent the Theater Commander the following +message: + +"FOR MACARTHUR, SIGNED MARSHALL: + +"GROVES HAS ORDERED FARRELL AT TINIAN TO ORGANIZE A SCIENTIFIC GROUP OF +THREE SECTIONS FOR POTENTIAL USE IN JAPAN IF SUCH USE SHOULD BE DESIRED. +THE FIRST GROUP IS FOR HIROSHIMA, THE SECOND FOR NAGASAKI, AND THE THIRD +FOR THE PURPOSE OF SECURING INFORMATION CONCERNING GENERAL JAPANESE +ACTIVITIES IN THE FIELD OF ATOMIC WEAPONS. THE GROUPS FOR HIROSHIMA AND +NAGASAKI SHOULD ENTER THOSE CITIES WITH THE FIRST AMERICAN TROOPS IN ORDER +THAT THESE TROOPS SHALL NOT BE SUBJECTED TO ANY POSSIBLE TOXIC EFFECTS +ALTHOUGH WE HAVE NO REASON TO BELIEVE THAT ANY SUCH EFFECTS ACTUALLY EXIST. +FARRELL AND HIS ORGANIZATION HAVE ALL AVAILABLE INFORMATION ON THIS +SUBJECT." + +General Farrell arrived in Yokohama on 30 August, with the Commanding +General of the 8th Army; Colonel Warren, who was Chief of the Radiological +Division of the District, arrived on 7 September. The main body of the +investigating group followed later. Preliminary inspections of Hiroshima +and Nagasaki were made on 8-9 and 13-14 September, respectively. Members +of the press had been enabled to precede General Farrell to Hiroshima. + +The special groups spent 16 days in Nagasaki and 4 days in Hiroshima, +during which time they collected as much information as was possible under +their directives which called for a prompt report. After General Farrell +returned to the U.S. to make his preliminary report, the groups were headed +by Brigadier General J. B. Newman, Jr. More extensive surveys have been +made since that time by other agencies who had more time and personnel +available for the purpose, and much of their additional data has thrown +further light on the effects of the bombings. This data has been duly +considered in the making of this report. + + + +PROPAGANDA + + +On the day after the Hiroshima strike, General Farrell received +instructions from the War Department to engage in a propaganda campaign +against the Japanese Empire in connection with the new weapon and its use +against Hiroshima. The campaign was to include leaflets and any other +propaganda considered appropriate. With the fullest cooperation from +CINCPAC of the Navy and the United States Strategic Air Forces, he +initiated promptly a campaign which included the preparation and +distribution of leaflets, broadcasting via short wave every 15 minutes over +radio Saipan and the printing at Saipan and distribution over the Empire of +a Japanese language newspaper which included the description and +photographs of the Hiroshima strike. + +The campaign proposed: + +1. Dropping 16,000,000 leaflets in a period of 9 days on 47 Japanese cities +with population of over 100,000. These cities represented more than 40% of +the total population. + +2. Broadcast of propaganda at regular intervals over radio Saipan. + +3. Distribution of 500,000 Japanese language newspapers containing +stories and pictures of the atomic bomb attacks. + +The campaign continued until the Japanese began their surrender +negotiations. At that time some 6,000,000 leaflets and a large number of +newspapers had been dropped. The radio broadcasts in Japanese had been +carried out at regular 15 minute intervals. + + + +SUMMARY OF DAMAGES AND INJURIES + + +Both the Hiroshima and the Nagasaki atomic bombs exhibited similar effects. + +The damages to man-made structures and other inanimate objects was the +result in both cities of the following effects of the explosions: + +A. Blast, or pressure wave, similar to that of normal explosions. + +B. Primary fires, i.e., those fires started instantaneously by the heat +radiated from the atomic explosion. + +C. Secondary fires, i.e., those fires resulting from the collapse of +buildings, damage to electrical systems, overturning of stoves, and other +primary effects of the blast. + +D. Spread of the original fires (B and C) to other structures. + +The casualties sustained by the inhabitants of both cities were due to: + +A. "Flash" burns, caused directly by the almost instantaneous radiation of +heat and light at the moment of the explosion. + +B. Burns resulting from the fires caused by the explosion. + +C. Mechanical injuries caused by collapse of buildings, flying debris, +and forceable hurling - about of persons struck by the blast pressure +waves. + +D. Radiation injuries caused by the instantaneous penetrating radiation +(in many respects similar to excessive X-ray exposure) from the nuclear +explosion; all of these effective radiations occurred during the first +minute after initiation of the explosion, and nearly all occurred during +the first second of the explosion. + +No casualties were suffered as a result of any persistent radioactivity of +fission products of the bomb, or any induced radioactivity of objects near +the explosion. The gamma radiations emitted by the nuclear explosion did +not, of course, inflict any damage on structures. + +The number of casualties which resulted from the pure blast effect alone +(i.e., because of simple pressure) was probably negligible in comparison to +that caused by other effects. + +The central portions of the cities underneath the explosions suffered +almost complete destruction. The only surviving objects were the frames of +a small number of strong reinforced concrete buildings which were not +collapsed by the blast; most of these buildings suffered extensive damage +from interior fires, had their windows, doors, and partitions knocked out, +and all other fixtures which were not integral parts of the reinforced +concrete frames burned or blown away; the casualties in such buildings near +the center of explosion were almost 100%. In Hiroshima fires sprang up +simultaneously all over the wide flat central area of the city; these fires +soon combined in an immense "fire storm" (high winds blowing inwards toward +the center of a large conflagration) similar to those caused by ordinary +mass incendiary raids; the resulting terrific conflagration burned out +almost everything which had not already been destroyed by the blast in a +roughly circular area of 4.4 square miles around the point directly under +the explosion (this point will hereafter in this report be referred to as +X). Similar fires broke out in Nagasaki, but no devastating fire storm +resulted as in Hiroshima because of the irregular shape of the city. + +In both cities the blast totally destroyed everything within a radius of 1 +mile from the center of explosion, except for certain reinforced concrete +frames as noted above. The atomic explosion almost completely destroyed +Hiroshima's identity as a city. Over a fourth of the population was killed +in one stroke and an additional fourth seriously injured, so that even if +there had been no damage to structures and installations the normal city +life would still have been completely shattered. Nearly everything was +heavily damaged up to a radius of 3 miles from the blast, and beyond this +distance damage, although comparatively light, extended for several more +miles. Glass was broken up to 12 miles. + +In Nagasaki, a smaller area of the city was actually destroyed than in +Hiroshima, because the hills which enclosed the target area restricted the +spread of the great blast; but careful examination of the effects of the +explosion gave evidence of even greater blast effects than in Hiroshima. +Total destruction spread over an area of about 3 square miles. Over a +third of the 50,000 buildings in the target area of Nagasaki were destroyed +or seriously damaged. The complete destruction of the huge steel works and +the torpedo plant was especially impressive. The steel frames of all +buildings within a mile of the explosion were pushed away, as by a giant +hand, from the point of detonation. The badly burned area extended for 3 +miles in length. The hillsides up to a radius of 8,000 feet were scorched, +giving them an autumnal appearance. + + + +MAIN CONCLUSIONS + + +The following are the main conclusions which were reached after thorough +examination of the effects of the bombs dropped on Hiroshima and Nagasaki: + +1. No harmful amounts of persistent radioactivity were present after the +explosions as determined by: + +A. Measurements of the intensity of radioactivity at the time of the +investigation; and + +B. Failure to find any clinical evidence of persons harmed by persistent +radioactivity. + +The effects of the atomic bombs on human beings were of three main types: + +A. Burns, remarkable for (1) the great ground area over which they were +inflicted and (2) the prevalence of "flash" burns caused by the +instantaneous heat radiation. + +B. Mechanical injuries, also remarkable for the wide area in which +suffered. + +C. Effects resulting from penetrating gamma radiation. The effects from +radiation were due to instantaneous discharge of radiation at the moment of +explosion and not to persistent radioactivity (of either fission products +or other substances whose radioactivity might have been induced by +proximity to the explosions). + +The effects of the atomic bombs on structures and installations were of two +types: + +A. Destruction caused by the great pressure from the blast; and + +B. Destruction caused by the fires, either started directly by the great +heat radiation, or indirectly through the collapse of buildings, wiring, +etc. + +4. The actual tonnage of T.N.T. which would have caused the same blast +damage was approximately of the order of 20,000 tons. + +5. In respect to their height of burst, the bombs performed exactly +according to design. + +6. The bombs were placed in such positions that they could not have done +more damage from any alternative bursting point in either city. + +7. The heights of burst were correctly chosen having regard to the type of +destruction it was desired to cause. + +8. The information collected would enable a reasonably accurate prediction +to be made of the blast damage likely to be caused in any city where an +atomic explosion could be effected. + + + +THE SELECTION OF THE TARGET + + +Some of the most frequent queries concerning the atomic bombs are those +dealing with the selection of the targets and the decision as to when the +bombs would be used. + +The approximate date for the first use of the bomb was set in the fall of +1942 after the Army had taken over the direction of and responsibility for +the atomic bomb project. At that time, under the scientific assumptions +which turned out to be correct, the summer of 1945 was named as the most +likely date when sufficient production would have been achieved to make it +possible actually to construct and utilize an atomic bomb. It was +essential before this time to develop the technique of constructing and +detonating the bomb and to make an almost infinite number of scientific and +engineering developments and tests. Between the fall of 1942 and June +1945, the estimated probabilities of success had risen from about 60% to +above 90%; however, not until July 16, 1945, when the first full-scale test +took place in New Mexico, was it conclusively proven that the theories, +calculations, and engineering were correct and that the bomb would be +successful. + + +The test in New Mexico was held 6 days after sufficient material had become +available for the first bomb. The Hiroshima bomb was ready awaiting +suitable weather on July 31st, and the Nagasaki bomb was used as soon after +the Hiroshima bomb as it was practicable to operate the second mission. + +The work on the actual selection of targets for the atomic bomb was begun +in the spring of 1945. This was done in close cooperation with the +Commanding General, Army Air Forces, and his Headquarters. A number of +experts in various fields assisted in the study. These included +mathematicians, theoretical physicists, experts on the blast effects of +bombs, weather consultants, and various other specialists. Some of the +important considerations were: + +A. The range of the aircraft which would carry the bomb. + +B. The desirability of visual bombing in order to insure the most +effective use of the bomb. + +C. Probable weather conditions in the target areas. + +D. Importance of having one primary and two secondary targets for each +mission, so that if weather conditions prohibited bombing the target there +would be at least two alternates. + +E. Selection of targets to produce the greatest military effect on the +Japanese people and thereby most effectively shorten the war. + +F. The morale effect upon the enemy. + +These led in turn to the following: + +A. Since the atomic bomb was expected to produce its greatest amount of +damage by primary blast effect, and next greatest by fires, the targets +should contain a large percentage of closely-built frame buildings and +other construction that would be most susceptible to damage by blast and +fire. + +B. The maximum blast effect of the bomb was calculated to extend over an +area of approximately 1 mile in radius; therefore the selected targets +should contain a densely built-up area of at least this size. + +C. The selected targets should have a high military strategic value. + +D. The first target should be relatively untouched by previous bombing, in +order that the effect of a single atomic bomb could be determined. + +The weather records showed that for five years there had never been two +successive good visual bombing days over Tokyo, indicating what might be +expected over other targets in the home islands. The worst month of the +year for visual bombing was believed to be June, after which the weather +should improve slightly during July and August and then become worse again +during September. Since good bombing conditions would occur rarely, the +most intense plans and preparations were necessary in order to secure +accurate weather forecasts and to arrange for full utilization of whatever +good weather might occur. It was also very desirable to start the raids +before September. + + + +DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS + + +Hiroshima + +The city of Hiroshima is located on the broad, flat delta of the Ota River, +which has 7 channel outlets dividing the city into six islands which +project into Hiroshima Bay. The city is almost entirely flat and only +slightly above sea level; to the northwest and northeast of the city some +hills rise to 700 feet. A single hill in the eastern part of the city +proper about 1/2 mile long and 221 feet in height interrupted to some +extent the spreading of the blast damage; otherwise the city was fully +exposed to the bomb. Of a city area of over 26 square miles, only 7 +square miles were completely built-up. There was no marked separation of +commercial, industrial, and residential zones. 75% of the population was +concentrated in the densely built-up area in the center of the city. + +Hiroshima was a city of considerable military importance. It contained the +2nd Army Headquarters, which commanded the defense of all of southern +Japan. The city was a communications center, a storage point, and an +assembly area for troops. To quote a Japanese report, "Probably more than +a thousand times since the beginning of the war did the Hiroshima citizens +see off with cries of 'Banzai' the troops leaving from the harbor." + +The center of the city contained a number of reinforced concrete buildings +as well as lighter structures. Outside the center, the area was congested +by a dense collection of small wooden workshops set among Japanese houses; +a few larger industrial plants lay near the outskirts of the city. The +houses were of wooden construction with tile roofs. Many of the industrial +buildings also were of wood frame construction. The city as a whole was +highly susceptible to fire damage. + +Some of the reinforced concrete buildings were of a far stronger +construction than is required by normal standards in America, because of +the earthquake danger in Japan. This exceptionally strong construction +undoubtedly accounted for the fact that the framework of some of the +buildings which were fairly close to the center of damage in the city did +not collapse. + +The population of Hiroshima had reached a peak of over 380,000 earlier in +the war but prior to the atomic bombing the population had steadily +decreased because of a systematic evacuation ordered by the Japanese +government. At the time of the attack the population was approximately +255,000. This figure is based on the registered population, used by the +Japanese in computing ration quantities, and the estimates of additional +workers and troops who were brought into the city may not be highly +accurate. Hiroshima thus had approximately the same number of people as +the city of Providence, R.I., or Dallas, Tex. + + +Nagasaki + +Nagasaki lies at the head of a long bay which forms the best natural harbor +on the southern Japanese home island of Kyushu. The main commercial and +residential area of the city lies on a small plain near the end of the bay. +Two rivers divided by a mountain spur form the two main valleys in which +the city lies. This mountain spur and the irregular lay-out of the city +tremendously reduced the area of destruction, so that at first glance +Nagasaki appeared to have been less devastated than Hiroshima. + +The heavily build-up area of the city is confined by the terrain to less +than 4 square miles out of a total of about 35 square miles in the city as +a whole. + +The city of Nagasaki had been one of the largest sea ports in southern +Japan and was of great war-time importance because of its many and varied +industries, including the production of ordnance, ships, military +equipment, and other war materials. The narrow long strip attacked was of +particular importance because of its industries. + +In contrast to many modern aspects of Nagasaki, the residences almost +without exception were of flimsy, typical Japanese construction, consisting +of wood or wood-frame buildings, with wood walls with or without plaster, +and tile roofs. Many of the smaller industries and business establishments +were also housed in wooden buildings or flimsily built masonry buildings. +Nagasaki had been permitted to grow for many years without conforming to +any definite city zoning plan and therefore residences were constructed +adjacent to factory buildings and to each other almost as close as it was +possible to build them throughout the entire industrial valley. + + + +THE ATTACKS + + +Hiroshima + +Hiroshima was the primary target of the first atomic bomb mission. The +mission went smoothly in every respect. The weather was good, and the +crew and equipment functioned perfectly. In every detail, the attack was +carried out exactly as planned, and the bomb performed exactly as expected. + +The bomb exploded over Hiroshima at 8:15 on the morning of August 6, 1945. +About an hour previously, the Japanese early warning radar net had detected +the approach of some American aircraft headed for the southern part of +Japan. The alert had been given and radio broadcasting stopped in many +cities, among them Hiroshima. The planes approached the coast at a very +high altitude. At nearly 8:00 A.M., the radar operator in Hiroshima +determined that the number of planes coming in was very small - probably +not more than three - and the air raid alert was lifted. The normal radio +broadcast warning was given to the people that it might be advisable to go +to shelter if B-29's were actually sighted, but no raid was expected beyond +some sort of reconnaissance. At 8:15 A.M., the bomb exploded with a +blinding flash in the sky, and a great rush of air and a loud rumble of +noise extended for many miles around the city; the first blast was soon +followed by the sounds of falling buildings and of growing fires, and a +great cloud of dust and smoke began to cast a pall of darkness over the +city. + +At 8:16 A.M., the Tokyo control operator of the Japanese Broadcasting +Corporation noticed that the Hiroshima station had gone off the air. He +tried to use another telephone line to reestablish his program, but it too +had failed. About twenty minutes later the Tokyo railroad telegraph center +realized that the main line telegraph had stopped working just north of +Hiroshima. From some small railway stops within ten miles of the city +there came unofficial and confused reports of a terrible explosion in +Hiroshima. All these reports were transmitted to the Headquarters of the +Japanese General Staff. + +Military headquarters repeatedly tried to call the Army Control Station in +Hiroshima. The complete silence from that city puzzled the men at +Headquarters; they knew that no large enemy raid could have occurred, and +they knew that no sizeable store of explosives was in Hiroshima at that +time. A young officer of the Japanese General Staff was instructed to fly +immediately to Hiroshima, to land, survey the damage, and return to Tokyo +with reliable information for the staff. It was generally felt at +Headquarters that nothing serious had taken place, that it was all a +terrible rumor starting from a few sparks of truth. + +The staff officer went to the airport and took off for the southwest. +After flying for about three hours, while still nearly 100 miles from +Hiroshima, he and his pilot saw a great cloud of smoke from the bomb. In +the bright afternoon, the remains of Hiroshima were burning. + +Their plane soon reached the city, around which they circled in disbelief. +A great scar on the land, still burning, and covered by a heavy cloud of +smoke, was all that was left of a great city. They landed south of the +city, and the staff officer immediately began to organize relief measures, +after reporting to Tokyo. + +Tokyo's first knowledge of what had really caused the disaster came from +the White House public announcement in Washington sixteen hours after +Hiroshima had been hit by the atomic bomb. + + +Nagasaki + +Nagasaki had never been subjected to large scale bombing prior to the +explosion of the atomic bomb there. On August 1st, 1945, however, a number +of high explosive bombs were dropped on the city. A few of these bombs hit +in the shipyards and dock areas in the southwest portion of the city. +Several of the bombs hit the Mitsubishi Steel and Arms Works and six bombs +landed at the Nagasaki Medical School and Hospital, with three direct hits +on buildings there. While the damage from these few bombs were relatively +small, it created considerable concern in Nagasaki and a number of people, +principally school children, were evacuated to rural areas for safety, thus +reducing the population in the city at the time of the atomic attack. + +On the morning of August 9th, 1945, at about 7:50 A.M., Japanese time, an +air raid alert was sounded in Nagasaki, but the "All clear" signal was +given at 8:30. When only two B-29 superfortresses were sighted at 10:53 +the Japanese apparently assumed that the planes were only on reconnaissance +and no further alarm was given. A few moments later, at 11:00 o'clock, the +observation B-29 dropped instruments attached to three parachutes and at +11:02 the other plane released the atomic bomb. + +The bomb exploded high over the industrial valley of Nagasaki, almost +midway between the Mitsubishi Steel and Arms Works, in the south, and the +Mitsubishi-Urakami Ordnance Works (Torpedo Works), in the north, the two +principal targets of the city. + +Despite its extreme importance, the first bombing mission on Hiroshima had +been almost routine. The second mission was not so uneventful. Again the +crew was specially trained and selected; but bad weather introduced some +momentous complications. These complications are best described in the +brief account of the mission's weaponeer, Comdr., now Capt., F. L. +Ashworth, U.S.N., who was in technical command of the bomb and was charged +with the responsibility of insuring that the bomb was successfully dropped +at the proper time and on the designated target. His narrative runs as +follows: + +"The night of our take-off was one of tropical rain squalls, and flashes of +lightning stabbed into the darkness with disconcerting regularity. The +weather forecast told us of storms all the way from the Marianas to the +Empire. Our rendezvous was to be off the southeast coast of Kyushu, some +1500 miles away. There we were to join with our two companion observation +B-29's that took off a few minutes behind us. Skillful piloting and expert +navigation brought us to the rendezvous without incident. + +"About five minutes after our arrival, we were joined by the first of our +B-29's. The second, however, failed to arrive, having apparently been +thrown off its course by storms during the night. We waited 30 minutes and +then proceeded without the second plane toward the target area. + +"During the approach to the target the special instruments installed in the +plane told us that the bomb was ready to function. We were prepared to +drop the second atomic bomb on Japan. But fate was against us, for the +target was completely obscured by smoke and haze. Three times we attempted +bombing runs, but without success. Then with anti-aircraft fire bursting +around us and with a number of enemy fighters coming up after us, we headed +for our secondary target, Nagasaki. + +"The bomb burst with a blinding flash and a huge column of black smoke +swirled up toward us. Out of this column of smoke there boiled a great +swirling mushroom of gray smoke, luminous with red, flashing flame, that +reached to 40,000 feet in less than 8 minutes. Below through the clouds we +could see the pall of black smoke ringed with fire that covered what had +been the industrial area of Nagasaki. + +"By this time our fuel supply was dangerously low, so after one quick +circle of Nagasaki, we headed direct for Okinawa for an emergency landing +and refueling". + + + +GENERAL COMPARISON OF HIROSHIMA AND NAGASAKI + + +It was not at first apparent to even trained observers visiting the two +Japanese cities which of the two bombs had been the most effective. + +In some respects, Hiroshima looked worse than Nagasaki. The fire damage in +Hiroshima was much more complete; the center of the city was hit and +everything but the reinforced concrete buildings had virtually disappeared. +A desert of clear-swept, charred remains, with only a few strong building +frames left standing was a terrifying sight. + +At Nagasaki there were no buildings just underneath the center of +explosion. The damage to the Mitsubishi Arms Works and the Torpedo Works +was spectacular, but not overwhelming. There was something left to see, +and the main contours of some of the buildings were still normal. + +An observer could stand in the center of Hiroshima and get a view of the +most of the city; the hills prevented a similar overall view in Nagasaki. +Hiroshima impressed itself on one's mind as a vast expanse of desolation; +but nothing as vivid was left in one's memory of Nagasaki. + +When the observers began to note details, however, striking differences +appeared. Trees were down in both cities, but the large trees which fell +in Hiroshima were uprooted, while those in Nagasaki were actually snapped +off. A few reinforced concrete buildings were smashed at the center in +Hiroshima, but in Nagasaki equally heavy damage could be found 2,300 feet +from X. In the study of objects which gave definite clues to the blast +pressure, such as squashed tin cans, dished metal plates, bent or snapped +poles and like, it was soon evident that the Nagasaki bomb had been much +more effective than the Hiroshima bomb. In the description of damage which +follows, it will be noted that the radius for the amount of damage was +greater in Nagasaki than Hiroshima. + + + +GENERAL DESCRIPTION OF DAMAGE CAUSED BY THE ATOMIC EXPLOSIONS + + +In considering the devastation in the two cities, it should be remembered +that the cities' differences in shape and topography resulted in great +differences in the damages. Hiroshima was all on low, flat ground, and was +roughly circular in shape; Nagasaki was much cut up by hills and mountain +spurs, with no regularity to its shape. + +In Hiroshima almost everything up to about one mile from X was completely +destroyed, except for a small number (about 50) of heavily reinforced +concrete buildings, most of which were specially designed to withstand +earthquake shock, which were not collapsed by the blast; most of these +buildings had their interiors completely gutted, and all windows, doors, +sashes, and frames ripped out. In Nagasaki, nearly everything within 1/2 +mile of the explosion was destroyed, including heavy structures. All +Japanese homes were destroyed within 1 1/2 miles from X. + +Underground air raid shelters with earth cover roofs immediately below the +explosion had their roofs caved in; but beyond 1/2 mile from X they +suffered no damage. + +In Nagasaki, 1500 feet from X high quality steel frame buildings were not +completely collapsed, but the entire buildings suffered mass distortion and +all panels and roofs were blown in. + +In Nagasaki, 2,000 feet from X, reinforced concrete buildings with 10" +walls and 6" floors were collapsed; reinforced concrete buildings with 4" +walls and roofs were standing but were badly damaged. At 2,000 feet some +9" concrete walls were completely destroyed. + +In Nagasaki, 3,500 feet from X, church buildings with 18" brick walls were +completely destroyed. 12" brick walls were severely cracked as far as +5,000 feet. + +In Hiroshima, 4,400 feet from X, multi-story brick buildings were +completely demolished. In Nagasaki, similar buildings were destroyed to +5,300 feet. + +In Hiroshima, roof tiles were bubbled (melted) by the flash heat out to +4,000 feet from X; in Nagasaki, the same effect was observed to 6,500 feet. + +In Hiroshima, steel frame buildings were destroyed 4,200 feet from X, and +to 4,800 feet in Nagasaki. + +In both cities, the mass distortion of large steel buildings was observed +out to 4,500 feet from X. + +In Nagasaki, reinforced concrete smoke stacks with 8" walls, specially +designed to withstand earthquake shocks, were overturned up to 4,000 feet +from X. + +In Hiroshima, steel frame buildings suffered severe structural damage up to +5,700 feet from X, and in Nagasaki the same damage was sustained as far as +6,000 feet. + +In Nagasaki, 9" brick walls were heavily cracked to 5,000 feet, were +moderately cracked to 6,000 feet, and slightly cracked to 8,000 feet. In +both cities, light concrete buildings collapsed out to 4,700 feet. + +In Hiroshima, multi-story brick buildings suffered structural damage up to +6,600 feet, and in Nagasaki up to 6,500 feet from X. + +In both cities overhead electric installations were destroyed up to 5,500 +feet; and trolley cars were destroyed up to 5,500 feet, and damaged to +10,500 feet. + +Flash ignition of dry, combustible material was observed as far as 6,400 +feet from X in Hiroshima, and in Nagasaki as far as 10,000 feet from X. + +Severe damage to gas holders occured out to 6,500 feet in both cities. + +All Japanese homes were seriously damaged up to 6,500 feet in Hiroshima, +and to 8,000 feet in Nagasaki. Most Japanese homes were damaged up to +8,000 feet in Hiroshima and 10,500 feet in Nagasaki. + +The hillsides in Nagasaki were scorched by the flash radiation of heat as +far as 8,000 feet from X; this scorching gave the hillsides the appearance +of premature autumn. + +In Nagasaki, very heavy plaster damage was observed in many buildings up to +9,000 feet; moderate damage was sustained as far as 12,000 feet, and light +damage up to 15,000 feet. + +The flash charring of wooden telegraph poles was observed up to 9,500 feet +from X in Hiroshima, and to 11,000 feet in Nagasaki; some reports indicate +flash burns as far as 13,000 feet from X in both places. + +Severe displacement of roof tiles was observed up to 8,000 feet in +Hiroshima, and to 10,000 feet in Nagasaki. + +In Nagasaki, very heavy damage to window frames and doors was observed up +to 8,000 feet, and light damage up to 12,000 feet. + +Roofs and wall coverings on steel frame buildings were destroyed out to +11,000 feet. + +Although the sources of many fires were difficult to trace accurately, it +is believed that fires were started by primary heat radiation as far as +15,000 feet from X. + +Roof damage extended as far as 16,000 feet from X in Hiroshima and in +Nagasaki. + +The actual collapse of buildings was observed at the extreme range of +23,000 feet from X in Nagasaki. + +Although complete window damage was observed only up to 12,000 feet from X, +some window damage occurred in Nagasaki up to 40,000 feet, and actual +breakage of glass occured up to 60,000 feet. + +Heavy fire damage was sustained in a circular area in Hiroshima with a mean +radius of about 6,000 feet and a maximum radius of about 11,000 feet; +similar heavy damage occured in Nagasaki south of X up to 10,000 feet, +where it was stopped on a river course. + +In Hiroshima over 60,000 of 90,000 buildings were destroyed or severely +damaged by the atomic bomb; this figure represents over 67% of the city's +structures. + +In Nagasaki 14,000 or 27% of 52,000 residences were completely destroyed +and 5,40O, or 10% were half destroyed. Only 12% remained undamaged. This +destruction was limited by the layout of the city. The following is a +summary of the damage to buildings in Nagasaki as determined from a ground +survey made by the Japanese: + + Destruction of Buildings and Houses Number Percentage + (Compiled by Nagasaki Municipality) + + Total in Nagasaki (before atomic explosion) 50,000 100.0 + Blasted (not burned) 2,652 5.3 + Blasted and burned 11,494 23.0 + Blasted and/or burned 14,146 28.3 + Partially burned or blasted 5,441 10.9 + Total buildings and houses destroyed 19,587 39.2 + Undamaged 30,413 60.8 + +In Hiroshima, all utilities and transportation services were disrupted for +varying lengths of time. In general however services were restored about +as rapidly as they could be used by the depleted population. Through +railroad service was in order in Hiroshima on 8 August, and electric power +was available in most of the surviving parts on 7 August, the day after the +bombing. The reservoir of the city was not damaged, being nearly 2 miles +from X. However, 70,000 breaks in water pipes in buildings and dwellings +were caused by the blast and fire effects. Rolling transportation suffered +extensive damage. The damage to railroad tracks, and roads was +comparatively small, however. The electric power transmission and +distribution systems were badly wrecked. The telephone system was +approximately 80% damaged, and no service was restored until 15 August. + +Despite the customary Japanese lack of attention to sanitation measures, no +major epidemic broke out in the bombed cities. Although the conditions +following the bombings makes this fact seem surprising, the experience of +other bombed cities in both Germany and Japan show Hiroshima and Nagasaki +not to be isolated cases. + +The atomic explosion over Nagasaki affected an over-all area of +approximately 42.9 square miles of which about 8.5 square miles were water +and only about 9.8 square miles were built up, the remainder being +partially settled. Approximately 36% of the built up areas were seriously +damaged. The area most severely damaged had an average radius of about 1 +mile, and covered about 2.9 square miles of which 2.4 were built up. + +In Nagasaki, buildings with structural steel frames, principally the +Mitsubishi Plant as far as 6,000 feet from X were severely damaged; these +buildings were typical of wartime mill construction in America and Great +Britain, except that some of the frames were somewhat less substantial. +The damage consisted of windows broken out (100%), steel sashes ripped out +or bent, corrugated metal or corrugated asbestos roofs and sidings ripped +off, roofs bent or destroyed, roof trusses collapsed, columns bent and +cracked and concrete foundations for columns rotated. Damage to buildings +with structural steel frames was more severe where the buildings received +the effect of the blast on their sides than where the blast hit the ends of +buildings, because the buildings had more stiffness (resistance to negative +moment at the top of columns) in a longitudinal direction. Many of the +lightly constructed steel frame buildings collapsed completely while some +of the heavily constructed (to carry the weight of heavy cranes and loads) +were stripped of roof and siding, but the frames were only partially +injured. + +The next most seriously damaged area in Nagasaki lies outside the 2.9 +square miles just described, and embraces approximately 4.2 square miles of +which 29% was built up. The damage from blast and fire was moderate here, +but in some sections (portions of main business districts) many secondary +fires started and spread rapidly, resulting in about as much over-all +destruction as in areas much closer to X. + +An area of partial damage by blast and fire lies just outside the one just +described and comprises approximately 35.8 square miles. Of this area, +roughly 1/6th was built up and 1/4th was water. The extent of damage +varied from serious (severe damage to roofs and windows in the main +business section of Nagasaki, 2.5 miles from X), to minor (broken or +occasionally broken windows at a distance of 7 miles southeast of X). + +As intended, the bomb was exploded at an almost ideal location over +Nagasaki to do the maximum damage to industry, including the Mitsubishi +Steel and Arms Works, the Mitsubishi-Urakami Ordnance Works (Torpedo +Works), and numerous factories, factory training schools, and other +industrial establishments, with a minimum destruction of dwellings and +consequently, a minimum amount of casualties. Had the bomb been dropped +farther south, the Mitsubishi-Urakami Ordnance Works would not have been so +severely damaged, but the main business and residential districts of +Nagasaki would have sustained much greater damage casualties. + +Calculations show that the structural steel and reinforced concrete frames +which survived the blast fairly close to X could not have withstood the +estimated peak pressures developed against the total areas presented by the +sides and roof of the buildings. The survival of these frames is explained +by the fact that they were not actually required to withstand the peak +pressure because the windows were quickly knocked out and roof and siding +stripped off thereby reducing total area and relieving the pressure. While +this saved the building frame, it permitted severe damage to building +interior and contents, and injuries to the building occupants. Buildings +without large panel openings through which the pressure could dissipate +were completely crushed, even when their frames were as strong as those +which survived. + +The damage sustained by reinforced concrete buildings depended both on the +proximity to X and the type and strength of the reinforced concrete +construction. Some of the buildings with reinforced concrete frames also +had reinforced concrete walls, ceilings, and partitions, while others had +brick or concrete tile walls covered either with plaster or ornamental +stone, with partitions of metal, glass, and plaster. With the exception of +the Nagasaki Medical School and Hospital group, which was designed to +withstand earthquakes and was therefore of heavier construction than most +American structures, most of the reinforced concrete structures could be +classified only as fair, with concrete of low strength and density, with +many of the columns, beams, and slabs underdesigned and improperly +reinforced. These facts account for some of the structural failures which +occured. + +In general, the atomic bomb explosion damaged all windows and ripped out, +bent, or twisted most of the steel window or door sashes, ripped doors from +hinges, damaged all suspended wood, metal, and plaster ceilings. The blast +concussion also caused great damage to equipment by tumbling and battering. +Fires generally of secondary origin consumed practically all combustible +material, caused plaster to crack off, burned all wooden trim, stair +covering, wooden frames of wooden suspended ceilings, beds, mattresses, and +mats, and fused glass, ruined all equipment not already destroyed by the +blast, ruined all electrical wiring, plumbing, and caused spalling of +concrete columns and beams in many of the rooms. + +Almost without exception masonry buildings of either brick or stone within +the effective limits of the blast were severely damaged so that most of +them were flattened or reduced to rubble. The wreckage of a church, +approximately 1,800 feet east of X in Nagasaki, was one of the few masonry +buildings still recognizable and only portions of the walls of this +structure were left standing. These walls were extremely thick (about 2 +feet). The two domes of the church had reinforced concrete frames and +although they were toppled, they held together as units. + +Practically every wooden building or building with timber frame within 2.0 +miles of X was either completely destroyed or very seriously damaged, and +significant damage in Nagasaki resulted as far as 3 miles from X. Nearly +all such buildings collapsed and a very large number were consumed by fire. + +A reference to the various photographs depicting damage shows that although +most of the buildings within the effective limits of the blast were totally +destroyed or severely damaged, a large number of chimneys even close to X +were left standing, apparently uninjured by the concussion. One +explanation is that concrete chimneys are approximately cylindrical in +shape and consequently offer much less wind resistance than flat surfaces +such as buildings. Another explanation is that since the cities were +subject to typhoons the more modern chimneys were probably designed to +withstand winds of high velocity. It is also probable that most of the +recently constructed chimneys as well as the more modern buildings were +constructed to withstand the acceleration of rather severe earthquakes. +Since the bombs were exploded high in the air, chimneys relatively close to +X were subjected to more of a downward than a lateral pressure, and +consequently the overturning moment was much less than might have been +anticipated. + +Although the blast damaged many bridges to some extent, bridge damage was +on the whole slight in comparison to that suffered by buildings. The +damage varied from only damaged railings to complete destruction of the +superstructure. Some of the bridges were wrecked and the spans were shoved +off their piers and into the river bed below by the force of the blast. +Others, particularly steel plate girder bridges, were badly buckled by the +blast pressure. None of the failures observed could be attributed to +inadequate design or structural weaknesses. + +The roads, and railroad and street railway trackage sustained practically +no primary damage as a result of the explosion. Most of the damage to +railroads occurred from secondary causes, such as fires and damage to +bridges or other structures. Rolling stock, as well as automobiles, +trolleys, and buses were destroyed and burned up to a considerable distance +from X. Streets were impassable for awhile because of the debris, but they +were not damaged. The height of the bomb explosion probably explains the +absence of direct damage to railroads and roads. + +A large part of the electric supply was interrupted by the bomb blast +chiefly through damage to electric substations and overhead transmission +systems. Both gas works in Nagasaki were severely damaged by the bomb. +These works would have required 6-7 months to get into operation. In +addition to the damage sustained by the electrical and gas systems, severe +damage to the water supply system was reported by the Japanese government; +the chief damage was a number of breaks in the large water mains and in +almost all of the distributing pipes in the areas which were affected by +the blast. Nagasaki was still suffering from a water shortage inside the +city six weeks after the atomic attack. + +The Nagasaki Prefectural report describes vividly the effects of the bomb +on the city and its inhabitants: + +"Within a radius of 1 kilometer from X, men and animals died almost +instantaneously and outside a radius of 1 kilometer and within a radius of +2 kilometers from X, some men and animals died instantly from the great +blast and heat but the great majority were seriously or superficially +injured. Houses and other structures were completely destroyed while fires +broke out everywhere. Trees were uprooted and withered by the heat. + +"Outside a radius of 2 kilometers and within a radius of 4 kilometers from +X, men and animals suffered various degrees of injury from window glass and +other fragments scattered about by the blast and many were burned by the +intense heat. Dwellings and other structures were half damaged by blast. + +"Outside a radius of 4 kilometers and within a radius of 8 kilometers +living creatures were injured by materials blown about by the blast; the +majority were only superficially wounded. Houses were only half or +partially damaged." + +The British Mission to Japan interpreted their observations of the +destruction of buildings to apply to similar construction of their own as +follows: + +A similar bomb exploding in a similar fashion would produce the following +effects on normal British houses: + +Up to 1,000 yards from X it would cause complete collapse. + +Up to 1 mile from X it would damage the houses beyond repair. + +Up to 1.5 miles from X it would render them uninhabitable without extensive +repair, particularly to roof timbers. + +Up to 2.5 miles from X it would render them uninhabitable until first-aid +repairs had been carried out. + +The fire damage in both cities was tremendous, but was more complete in +Hiroshima than in Nagasaki. The effect of the fires was to change +profoundly the appearance of the city and to leave the central part bare, +except for some reinforced concrete and steel frames and objects such as +safes, chimney stacks, and pieces of twisted sheet metal. The fire damage +resulted more from the properties of the cities themselves than from those +of the bombs. + +The conflagration in Hiroshima caused high winds to spring up as air was +drawn in toward the center of the burning area, creating a "fire storm". +The wind velocity in the city had been less than 5 miles per hour before +the bombing, but the fire-wind attained a velocity of 30-40 miles per hour. +These great winds restricted the perimeter of the fire but greatly added to +the damage of the conflagration within the perimeter and caused the deaths +of many persons who might otherwise have escaped. In Nagasaki, very severe +damage was caused by fires, but no extensive "fire storm" engulfed the +city. In both cities, some of the fires close to X were no doubt started +by the ignition of highly combustible material such as paper, straw, and +dry cloth, upon the instantaneous radiation of heat from the nuclear +explosion. The presence of large amounts of unburnt combustible materials +near X, however, indicated that even though the heat of the blast was very +intense, its duration was insufficient to raise the temperature of many +materials to the kindling point except in cases where conditions were +ideal. The majority of the fires were of secondary origin starting from +the usual electrical short-circuits, broken gas lines, overturned stoves, +open fires, charcoal braziers, lamps, etc., following collapse or serious +damage from the direct blast. + +Fire fighting and rescue units were stripped of men and equipment. Almost +30 hours elapsed before any rescue parties were observable. In Hiroshima +only a handful of fire engines were available for fighting the ensuing +fires, and none of these were of first class type. In any case, however, +it is not likely that any fire fighting equipment or personnel or +organization could have effected any significant reduction in the amount of +damage caused by the tremendous conflagration. + +A study of numerous aerial photographs made prior to the atomic bombings +indicates that between 10 June and 9 August 1945 the Japanese constructed +fire breaks in certain areas of the cities in order to control large scale +fires. In general these fire breaks were not effective because fires were +started at so many locations simultaneously. They appear, however, to have +helped prevent fires from spreading farther east into the main business and +residential section of Nagasaki. + + + +TOTAL CASUALTIES + + +There has been great difficulty in estimating the total casualties in the +Japanese cities as a result of the atomic bombing. The extensive +destruction of civil installations (hospitals, fire and police +department, and government agencies) the state of utter confusion +immediately following the explosion, as well as the uncertainty regarding +the actual population before the bombing, contribute to the difficulty of +making estimates of casualties. The Japanese periodic censuses are not +complete. Finally, the great fires that raged in each city totally +consumed many bodies. + +The number of total casualties has been estimated at various times since +the bombings with wide discrepancies. The Manhattan Engineer District's +best available figures are: + +TABLE A + Estimates of Casualties + + Hiroshima Nagasaki + Pre-raid population 255,000 195,000 + Dead 66,000 39,000 + Injured 69,000 25,000 + Total Casualties 135,000 64,000 + +The relation of total casualties to distance from X, the center of damage +and point directly under the air-burst explosion of the bomb, is of great +importance in evaluating the casualty-producing effect of the bombs. This +relationship for the total population of Nagasaki is shown in the table +below, based on the first-obtained casualty figures of the District: + +TABLE B + Relation of Total Casualties to Distance from X + +Distance Total Killed per +from X, feet Killed Injured Missing Casualties square mile + 0 - 1,640 7,505 960 1,127 9,592 24,7OO +1,640 - 3,300 3,688 1,478 1,799 6,965 4,040 +3,300 - 4,900 8,678 17,137 3,597 29,412 5,710 +4,900 - 6,550 221 11,958 28 12,207 125 +6,550 - 9,850 112 9,460 17 9,589 20 + +No figure for total pre-raid population at these different distances were +available. Such figures would be necessary in order to compute per cent +mortality. A calculation made by the British Mission to Japan and based on +a preliminary analysis of the study of the Joint Medical-Atomic Bomb +Investigating Commission gives the following calculated values for per cent +mortality at increasing distances from X: + +TABLE C + Per-Cent Mortality at Various Distances + +Distance from X, Per-cent Mortality + in feet + 0 - 1000 93.0% +1000 - 2000 92.0 +2000 - 3000 86.0 +3000 - 4000 69.0 +4000 - 5000 49.0 +5000 - 6000 31.5 +6000 - 7000 12.5 +7000 - 8000 1.3 +8000 - 9000 0.5 +9000 - 10,000 0.0 + +It seems almost certain from the various reports that the greatest total +number of deaths were those occurring immediately after the bombing. The +causes of many of the deaths can only be surmised, and of course many +persons near the center of explosion suffered fatal injuries from more than +one of the bomb effects. The proper order of importance for possible +causes of death is: burns, mechanical injury, and gamma radiation. Early +estimates by the Japanese are shown in D below: + +TABLE D + Cause of Immediate Deaths + +City Cause of Death Per-cent of Total +Hiroshima Burns 60% + Falling debris 30 + Other 10 + +Nagasaki Burns 95% + Falling debris 9 + Flying glass 7 + Other 7 + + + +THE NATURE OF AN ATOMIC EXPLOSION + + +The most striking difference between the explosion of an atomic bomb and +that of an ordinary T.N.T. bomb is of course in magnitude; as the President +announced after the Hiroshima attack, the explosive energy of each of the +atomic bombs was equivalent to about 20,000 tons of T.N.T. + +But in addition to its vastly greater power, an atomic explosion has +several other very special characteristics. Ordinary explosion is a +chemical reaction in which energy is released by the rearrangement of the +atoms of the explosive material. In an atomic explosion the identity of +the atoms, not simply their arrangement, is changed. A considerable +fraction of the mass of the explosive charge, which may be uranium 235 or +plutonium, is transformed into energy. Einstein's equation, E = mc^2, +shows that matter that is transformed into energy may yield a total energy +equivalent to the mass multiplied by the square of the velocity of light. +The significance of the equation is easily seen when one recalls that the +velocity of light is 186,000 miles per second. The energy released when a +pound of T.N.T. explodes would, if converted entirely into heat, raise the +temperature of 36 lbs. of water from freezing temperature (32 deg F) to +boiling temperature (212 deg F). The nuclear fission of a pound of uranium +would produce an equal temperature rise in over 200 million pounds of +water. + +The explosive effect of an ordinary material such as T.N.T. is derived from +the rapid conversion of solid T.N.T. to gas, which occupies initially the +same volume as the solid; it exerts intense pressures on the surrounding +air and expands rapidly to a volume many times larger than the initial +volume. A wave of high pressure thus rapidly moves outward from the center +of the explosion and is the major cause of damage from ordinary high +explosives. An atomic bomb also generates a wave of high pressure which is +in fact of, much higher pressure than that from ordinary explosions; and +this wave is again the major cause of damage to buildings and other +structures. It differs from the pressure wave of a block buster in the +size of the area over which high pressures are generated. It also differs +in the duration of the pressure pulse at any given point: the pressure from +a blockbuster lasts for a few milliseconds (a millisecond is one thousandth +of a second) only, that from the atomic bomb for nearly a second, and was +felt by observers both in Japan and in New Mexico as a very strong wind +going by. + +The next greatest difference between the atomic bomb and the T.N.T. +explosion is the fact that the atomic bomb gives off greater amounts of +radiation. Most of this radiation is "light" of some wave-length ranging +from the so-called heat radiations of very long wave length to the +so-called gamma rays which have wave-lengths even shorter than the X-rays +used in medicine. All of these radiations travel at the same speed; this, +the speed of light, is 186,000 miles per second. The radiations are +intense enough to kill people within an appreciable distance from the +explosion, and are in fact the major cause of deaths and injuries apart +from mechanical injuries. The greatest number of radiation injuries was +probably due to the ultra-violet rays which have a wave length slightly +shorter than visible light and which caused flash burn comparable to severe +sunburn. After these, the gamma rays of ultra short wave length are most +important; these cause injuries similar to those from over-doses of X-rays. + +The origin of the gamma rays is different from that of the bulk of the +radiation: the latter is caused by the extremely high temperatures in the +bomb, in the same way as light is emitted from the hot surface of the sun +or from the wires in an incandescent lamp. The gamma rays on the other +hand are emitted by the atomic nuclei themselves when they are transformed +in the fission process. The gamma rays are therefore specific to the +atomic bomb and are completely absent in T.N.T. explosions. The light of +longer wave length (visible and ultra-violet) is also emitted by a T.N.T. +explosion, but with much smaller intensity than by an atomic bomb, which +makes it insignificant as far as damage is concerned. + +A large fraction of the gamma rays is emitted in the first few microseconds +(millionths of a second) of the atomic explosion, together with neutrons +which are also produced in the nuclear fission. The neutrons have much +less damage effect than the gamma rays because they have a smaller +intensity and also because they are strongly absorbed in air and therefore +can penetrate only to relatively small distances from the explosion: at a +thousand yards the neutron intensity is negligible. After the nuclear +emission, strong gamma radiation continues to come from the exploded bomb. +This generates from the fission products and continues for about one minute +until all of the explosion products have risen to such a height that the +intensity received on the ground is negligible. A large number of beta +rays are also emitted during this time, but they are unimportant because +their range is not very great, only a few feet. The range of alpha +particles from the unused active material and fissionable material of the +bomb is even smaller. + +Apart from the gamma radiation ordinary light is emitted, some of which is +visible and some of which is the ultra violet rays mainly responsible for +flash burns. The emission of light starts a few milliseconds after the +nuclear explosion when the energy from the explosion reaches the air +surrounding the bomb. The observer sees then a ball of fire which rapidly +grows in size. During most of the early time, the ball of fire extends as +far as the wave of high pressure. As the ball of fire grows its +temperature and brightness decrease. Several milliseconds after the +initiation of the explosion, the brightness of the ball of fire goes +through a minimum, then it gets somewhat brighter and remains at the order +of a few times the brightness of the sun for a period of 10 to 15 seconds +for an observer at six miles distance. Most of the radiation is given off +after this point of maximum brightness. Also after this maximum, the +pressure waves run ahead of the ball of fire. + +The ball of fire rapidly expands from the size of the bomb to a radius of +several hundred feet at one second after the explosion. After this the +most striking feature is the rise of the ball of fire at the rate of about +30 yards per second. Meanwhile it also continues to expand by mixing with +the cooler air surrounding it. At the end of the first minute the ball has +expanded to a radius of several hundred yards and risen to a height of +about one mile. The shock wave has by now reached a radius of 15 miles and +its pressure dropped to less than 1/10 of a pound per square inch. The +ball now loses its brilliance and appears as a great cloud of smoke: the +pulverized material of the bomb. This cloud continues to rise vertically +and finally mushrooms out at an altitude of about 25,000 feet depending +upon meteorological conditions. The cloud reaches a maximum height of +between 50,000 and 70,000 feet in a time of over 30 minutes. + +It is of interest to note that Dr. Hans Bethe, then a member of the +Manhattan Engineer District on loan from Cornell University, predicted the +existence and characteristics of this ball of fire months before the first +test was carried out. + +To summarize, radiation comes in two bursts - an extremely intense one +lasting only about 3 milliseconds and a less intense one of much longer +duration lasting several seconds. The second burst contains by far the +larger fraction of the total light energy, more than 90%. But the first +flash is especially large in ultra-violet radiation which is biologically +more effective. Moreover, because the heat in this flash comes in such a +short time, there is no time for any cooling to take place, and the +temperature of a person's skin can be raised 50 degrees centigrade by the +flash of visible and ultra-violet rays in the first millisecond at a +distance of 4,000 yards. People may be injured by flash burns at even +larger distances. Gamma radiation danger does not extend nearly so far and +neutron radiation danger is still more limited. + +The high skin temperatures result from the first flash of high intensity +radiation and are probably as significant for injuries as the total dosages +which come mainly from the second more sustained burst of radiation. The +combination of skin temperature increase plus large ultra-violet flux +inside 4,000 yards is injurious in all cases to exposed personnel. Beyond +this point there may be cases of injury, depending upon the individual +sensitivity. The infra-red dosage is probably less important because of its +smaller intensity. + + + +CHARACTERISTICS OF THE DAMAGE CAUSED BY THE ATOMIC BOMBS + + +The damage to man-made structures caused by the bombs was due to two +distinct causes: first the blast, or pressure wave, emanating from the +center of the explosion, and, second, the fires which were caused either by +the heat of the explosion itself or by the collapse of buildings containing +stoves, electrical fixtures, or any other equipment which might produce +what is known as a secondary fire, and subsequent spread of these fires. + +The blast produced by the atomic bomb has already been stated to be +approximately equivalent to that of 20,000 tons of T.N.T. Given this +figure, one may calculate the expected peak pressures in the air, at +various distances from the center of the explosion, which occurred +following detonation of the bomb. The peak pressures which were calculated +before the bombs were dropped agreed very closely with those which were +actually experienced in the cities during the attack as computed by Allied +experts in a number of ingenious ways after the occupation of Japan. + +The blast of pressure from the atomic bombs differed from that of ordinary +high explosive bombs in three main ways: + +A. Downward thrust. Because the explosions were well up in the air, much +of the damage resulted from a downward pressure. This pressure of course +most largely effected flat roofs. Some telegraph and other poles +immediately below the explosion remained upright while those at greater +distances from the center of damage, being more largely exposed to a +horizontal thrust from the blast pressure waves, were overturned or tilted. +Trees underneath the explosion remained upright but had their branches +broken downward. + +B. Mass distortion of buildings. An ordinary bomb can damage only a part +of a large building, which may then collapse further under the action of +gravity. But the blast wave from an atomic bomb is so large that it can +engulf whole buildings, no matter how great their size, pushing them over +as though a giant hand had given them a shove. + +C. Long duration of the positive pressure pulse and consequent small +effect of the negative pressure, or suction, phase. In any explosion, the +positive pressure exerted by the blast lasts for a definite period of time +(usually a small fraction of a second) and is then followed by a somewhat +longer period of negative pressure, or suction. The negative pressure is +always much weaker than the positive, but in ordinary explosions the short +duration of the positive pulse results in many structures not having time +to fail in that phase, while they are able to fail under the more extended, +though weaker, negative pressure. But the duration of the positive pulse +is approximately proportional to the 1/3 power of the size of the explosive +charge. Thus, if the relation held true throughout the range in question, +a 10-ton T.N.T. explosion would have a positive pulse only about 1/14th as +long as that of a 20,000-ton explosion. Consequently, the atomic +explosions had positive pulses so much longer then those of ordinary +explosives that nearly all failures probably occurred during this phase, +and very little damage could be attributed to the suction which followed. + +One other interesting feature was the combination of flash ignition and +comparative slow pressure wave. Some objects, such as thin, dry wooden +slats, were ignited by the radiated flash heat, and then their fires were +blown out some time later (depending on their distance from X) by the +pressure blast which followed the flash radiation. + + + +CALCULATIONS OF THE PEAK PRESSURE OF THE BLAST WAVE + + +Several ingenious methods were used by the various investigators to +determine, upon visiting the wrecked cities, what had actually been the +peak pressures exerted by the atomic blasts. These pressures were computed +for various distances from X, and curves were then plotted which were +checked against the theoretical predictions of what the pressures would be. +A further check was afforded from the readings obtained by the measuring +instruments which were dropped by parachute at each atomic attack. The +peak pressure figures gave a direct clue to the equivalent T.N.T. tonnage +of the atomic bombs, since the pressures developed by any given amount of +T.N.T. can be calculated easily. + +One of the simplest methods of estimating the peak pressure is from +crushing of oil drums, gasoline cans, or any other empty thin metal vessel +with a small opening. The assumption made is that the blast wave pressure +comes on instantaneously, the resulting pressure on the can is more than +the case can withstand, and the walls collapse inward. The air inside is +compressed adiabatically to such a point that the pressure inside is less +by a certain amount than the pressure outside, this amount being the +pressure difference outside and in that the walls can stand in their +crumpled condition. The uncertainties involved are, first, that some air +rushes in through any opening that the can may have, and thus helps to +build up the pressure inside; and, second, that as the pressure outside +falls, the air inside cannot escape sufficiently fast to avoid the walls of +the can being blown out again to some extent. These uncertainties are such +that estimates of pressure based on this method are on the low side, i.e., +they are underestimated. + +Another method of calculating the peak-pressure is through the bending of +steel flagpoles, or lightning conductors, away from the explosion. It is +possible to calculate the drag on a pole or rod in an airstream of a +certain density and velocity; by connecting this drag with the strength of +the pole in question, a determination of the pressure wave may be obtained. + +Still another method of estimating the peak pressure is through the +overturning of memorial stones, of which there are a great quantity in +Japan. The dimensions of the stones can be used along with known data on +the pressure exerted by wind against flat surfaces, to calculate the +desired figure. + + + +LONG RANGE BLAST DAMAGE + + +There was no consistency in the long range blast damage. Observers often +thought that they had found the limit, and then 2,000 feet farther away +would find further evidence of damage. + +The most impressive long range damage was the collapse of some of the +barracks sheds at Kamigo, 23,000 feet south of X in Nagasaki. It was +remarkable to see some of the buildings intact to the last details, +including the roof and even the windows, and yet next to them a similar +building collapsed to ground level. + +The limiting radius for severe displacement of roof tiles in Nagasaki was +about 10,000 feet although isolated cases were found up to 16,000 feet. +In Hiroshima the general limiting radius was about 8,000 feet; however, +even at a distance of 26,000 feet from X in Hiroshima, some tiles were +displaced. + +At Mogi, 7 miles from X in Nagasaki, over steep hills over 600 feet high, +about 10% of the glass came out. In nearer, sequestered localities only 4 +miles from X, no damage of any kind was caused. An interesting effect was +noted at Mogi; eyewitnesses said that they thought a raid was being made on +the place; one big flash was seen, then a loud roar, followed at several +second intervals by half a dozen other loud reports, from all directions. +These successive reports were obviously reflections from the hills +surrounding Mogi. + + + +GROUND SHOCK + + +The ground shock in most cities was very light. Water pipes still carried +water and where leaks were visible they were mainly above ground. +Virtually all of the damage to underground utilities was caused by the +collapse of buildings rather than by any direct exertion of the blast +pressure. This fact of course resulted from the bombs' having been +exploded high in the air. + + + +SHIELDING, OR SCREENING FROM BLAST + + +In any explosion, a certain amount of protection from blast may be gained +by having any large and substantial object between the protected object and +the center of the explosion. This shielding effect was noticeable in the +atomic explosions, just as in ordinary cases, although the magnitude of the +explosions and the fact that they occurred at a considerable height in the +air caused marked differences from the shielding which would have +characterized ordinary bomb explosions. + +The outstanding example of shielding was that afforded by the hills in the +city of Nagasaki; it was the shielding of these hills which resulted in the +smaller area of devastation in Nagasaki despite the fact that the bomb used +there was not less powerful. The hills gave effective shielding only at +such distances from the center of explosion that the blast pressure was +becoming critical - that is, was only barely sufficient to cause collapse - +for the structure. Houses built in ravines in Nagasaki pointing well away +from the center of the explosion survived without damage, but others at +similar distances in ravines pointing toward the center of explosion were +greatly damaged. In the north of Nagasaki there was a small hamlet about +8,000 feet from the center of explosion; one could see a distinctive +variation in the intensity of damage across the hamlet, corresponding with +the shadows thrown by a sharp hill. + +The best example of shielding by a hill was southeast of the center of +explosion in Nagasaki. The damage at 8,000 feet from X consisted of light +plaster damage and destruction of about half the windows. These buildings +were of European type and were on the reverse side of a steep hill. At the +same distance to the south-southeast the damage was considerably greater, +i.e., all windows and frames, doors, were damaged and heavy plaster damage +and cracks in the brick work also appeared. The contrast may be +illustrated also by the fact that at the Nagasaki Prefectural office at +10,800 feet the damage was bad enough for the building to be evacuated, +while at the Nagasaki Normal School to which the Prefectural office had +been moved, at the same distance, the damage was comparatively light. + +Because of the height of the bursts no evidence was expected of the +shielding of one building by another, at least up to a considerable radius. +It was in fact difficult to find any evidence at any distance of such +shielding. There appeared to have been a little shielding of the building +behind the Administration Building of the Torpedo Works in Nagasaki, but +the benefits were very slight. There was also some evidence that the group +of buildings comprising the Medical School in Nagasaki did afford each +other mutual protection. On the whole, however, shielding of one building +by another was not noticeable. + +There was one other peculiar type of shielding, best exhibited by the +workers' houses to the north of the torpedo plant in Nagasaki. These were +6,000 to 7,000 feet north of X. The damage to these houses was not nearly +as bad as those over a thousand feet farther away from the center of +explosion. It seemed as though the great destruction caused in the torpedo +plant had weakened the blast a little, and the full power was not restored +for another 1,000 feet or more. + + + +FLASH BURN + + +As already stated, a characteristic feature of the atomic bomb, which is +quite foreign to ordinary explosives, is that a very appreciable fraction +of the energy liberated goes into radiant heat and light. For a +sufficiently large explosion, the flash burn produced by this radiated +energy will become the dominant cause of damage, since the area of burn +damage will increase in proportion to the energy released, whereas the area +of blast damage increases only with the two-thirds power of the energy. +Although such a reversal of the mechanism of damage was not achieved in the +Hiroshima and Nagasaki bombs, the effects of the flash were, however, very +evident, and many casualties resulted from flash burns. A discussion of +the casualties caused by flash burns will be given later; in this section +will be described the other flash effects which were observed in the two +cities. + +The duration of the heat radiation from the bomb is so short, just a few +thousandths of a second, that there is no time for the energy falling on a +surface to be dissipated by thermal defusion; the flash burn is typically a +surface effect. In other words the surface of either a person or an object +exposed to the flash is raised to a very high temperature while immediately +beneath the surface very little rise in temperature occurs. + +The flash burning of the surface of objects, particularly wooden objects, +occurred in Hiroshima up to a radius of 9,500 feet from X; at Nagasaki +burns were visible up to 11,000 feet from X. The charring and blackening +of all telephone poles, trees and wooden posts in the areas not destroyed +by the general fire occurred only on the side facing the center of +explosion and did not go around the corners of buildings or hills. The +exact position of the explosion was in fact accurately determined by taking +a number of sights from various objects which had been flash burned on one +side only. + +To illustrate the effects of the flash burn, the following describes a +number of examples found by an observer moving northward from the center of +explosion in Nagasaki. First occurred a row of fence posts at the north +edge of the prison hill, at 0.3 miles from X. The top and upper part of +these posts were heavily charred. The charring on the front of the posts +was sharply limited by the shadow of a wall. This wall had however been +completely demolished by the blast, which of course arrived some time after +the flash. At the north edge of the Torpedo works, 1.05 miles from X, +telephone poles were charred to a depth of about 0.5 millimeters. A light +piece of wood similar to the flat side of an orange crate, was found +leaning against one of the telephone poles. Its front surface was charred +the same way as the pole, but it was evident that it had actually been +ignited. The wood was blackened through a couple of cracks and nail holes, +and around the edges onto the back surface. It seemed likely that this +piece of wood had flamed up under the flash for a few seconds before the +flame was blown out by the wind of the blast. Farther out, between 1.05 +and 1.5 miles from the explosion, were many trees and poles showing a +blackening. Some of the poles had platforms near the top. The shadows +cast by the platforms were clearly visible and showed that the bomb had +detonated at a considerable height. The row of poles turned north and +crossed the mountain ridge; the flash burn was plainly visible all the way +to the top of the ridge, the farthest burn observed being at 2.0 miles from +X. + +Another striking effect of the flash burn was the autumnal appearance of +the bowl formed by the hills on three sides of the explosion point. The +ridges are about 1.5 miles from X. Throughout this bowl the foliage turned +yellow, although on the far side of the ridges the countryside was quite +green. This autumnal appearance of the trees extended to about 8,000 feet +from X. + +However, shrubs and small plants quite near the center of explosion in +Hiroshima, although stripped of leaves, had obviously not been killed. +Many were throwing out new buds when observers visited the city. + +There are two other remarkable effects of the heat radiated from the bomb +explosion. The first of these is the manner in which heat roughened the +surface of polished granite, which retained its polish only where it was +shielded from the radiated heat travelling in straight lines from the +explosion. This roughening by radiated heat caused by the unequal +expansion of the constituent crystals of the stone; for granite crystals +the melting temperature is about 600 deg centigrade. Therefore the depth +of roughening and ultimate flaking of the granite surface indicated the +depth to which this temperature occurred and helped to determine the +average ground temperatures in the instant following the explosion. This +effect was noted for distances about 1 1/2 times as great in Nagasaki as in +Hiroshima. + +The second remarkable effect was the bubbling of roof tile. The size of +the bubbles and their extent was proportional to their nearness to the +center of explosion and also depended on how squarely the tile itself was +faced toward the explosion. The distance ratio of this effect between +Nagasaki and Hiroshima was about the same as for the flaking of polished +granite. + +Various other effects of the radiated heat were noted, including the +lightening of asphalt road surfaces in spots which had not been protected +from the radiated heat by any object such as that of a person walking along +the road. Various other surfaces were discolored in different ways by the +radiated heat. + +As has already been mentioned the fact that radiant heat traveled only in +straight lines from the center of explosion enabled observers to determine +the direction toward the center of explosion from a number of different +points, by observing the "shadows" which were cast by intervening objects +where they shielded the otherwise exposed surface of some object. Thus the +center of explosion was located with considerable accuracy. In a number of +cases these "shadows" also gave an indication of the height of burst of the +bomb and occasionally a distinct penumbra was found which enabled observers +to calculate the diameter of the ball of fire at the instant it was +exerting the maximum charring or burning effect. + +One more interesting feature connected with heat radiation was the charring +of fabric to different degrees depending upon the color of the fabric. A +number of instances were recorded in which persons wearing clothing of +various colors received burns greatly varying in degree, the degree of burn +depending upon the color of the fabric over the skin in question. For +example a shirt of alternate light and dark gray stripes, each about 1/8 of +an inch wide, had the dark stripes completely burned out but the light +stripes were undamaged; and a piece of Japanese paper exposed nearly 1 1/2 +miles from X had the characters which were written in black ink neatly +burned out. + + + +CHARACTERISTICS OF THE INJURIES TO PERSONS + + +Injuries to persons resulting from the atomic explosions were of the +following types: + + A. Burns, from + 1. Flash radiation of heat + 2. Fires started by the explosions. + B. Mechanical injuries from collapse of buildings, flying debris, etc. + C. Direct effects of the high blast pressure, i.e., straight +compression. + D. Radiation injuries, from the instantaneous emission of gamma rays and +neutrons. + +It is impossible to assign exact percentages of casualties to each of the +types of injury, because so many victims were injured by more than one +effect of the explosions. However, it is certain that the greater part of +the casualties resulted from burns and mechanical injures. Col. Warren, +one of America's foremost radioligists, stated it is probable that 7 per +cent or less of the deaths resulted primarily from radiation disease. + +The greatest single factor influencing the occurrence of casualties was the +distance of the person concerned from the center of explosion. + +Estimates based on the study of a selected group of 900 patients indicated +that total casualties occurred as far out as 14,000 feet at Nagasaki and +12,000 feet at Hiroshima. + +Burns were suffered at a considerable greater distance from X than any +other type of injury, and mechanical injuries farther out than radiation +effects. + +Medical findings show that no person was injured by radioactivity who was +not exposed to the actual explosion of the bombs. No injuries resulted +from persistent radioactivity of any sort. + + + +BURNS + + +Two types of burns were observed. These are generally differentiated as +flame or fire burn and so-called flash burn. + +The early appearance of the flame burn as reported by the Japanese, and the +later appearance as observed, was not unusual. + +The flash burn presented several distinctive features. Marked redness of +the affected skin areas appeared almost immediately, according to the +Japanese, with progressive changes in the skin taking place over a period +of a few hours. When seen after 50 days, the most distinctive feature of +these burns was their sharp limitation to exposed skin areas facing the +center of the explosion. For instance, a patient who had been walking in a +direction at right angles to a line drawn between him and the explosion, +and whose arms were swinging, might have burns only on the outside of the +arm nearest the center and on the inside of the other arm. + +Generally, any type of shielding protected the skin against flash burns, +although burns through one, and very occasionally more, layers of clothing +did occur in patients near the center. In such cases, it was not unusual +to find burns through black but not through white clothing, on the same +patient. Flash burns also tended to involve areas where the clothes were +tightly drawn over the skin, such as at the elbows and shoulders. + +The Japanese report the incidence of burns in patients surviving more than +a few hours after the explosion, and seeking medical attention, as high as +95%. The total mortalities due to burns alone cannot be estimated with any +degree of accuracy. As mentioned already, it is believed that the majority +of all the deaths occurred immediately. Of these, the Japanese estimate +that 75%, and most of the reports estimate that over 50%, of the deaths +were due to burns. + +In general, the incidence of burns was in direct proportion to the distance +from X. However, certain irregularities in this relationship result in the +medical studies because of variations in the amount of shielding from flash +burn, and because of the lack of complete data on persons killed outright +close to X. + +The maximum distance from X at which flash burns were observed is of +paramount interest. It has been estimated that patients with burns at +Hiroshima were all less than 7,500 feet from the center of the explosion at +the time of the bombing. At Nagasaki, patients with burns were observed +out to the remarkable distance of 13,800 feet. + + + +MECHANICAL INJURIES + + +The mechanical injuries included fractures, lacerations, contusions, +abrasions, and other effects to be expected from falling roofs, crumbling +walls, flying debris and glass, and other indirect blast effects. The +appearance of these various types of mechanical injuries was not remarkable +to the medical authorities who studied them. + +It was estimated that patients with lacerations at Hiroshima were less than +10,600 feet from X, whereas at Nagasaki they extended as far as 12,200 +feet. + +The tremendous drag of wind, even as far as 1 mile from X, must have +resulted in many injuries and deaths. Some large pieces of a prison wall, +for example, were flung 80 feet, and many have gone 30 feet high before +falling. The same fate must have befallen many persons, and the chances of +a human being surviving such treatment are probably small. + + + +BLAST INJURIES + + +No estimate of the number of deaths or early symptoms due to blast pressure +can be made. The pressures developed on the ground under the explosions +were not sufficient to kill more than those people very near the center of +damage (within a few hundred feet at most). Very few cases of ruptured ear +drums were noted, and it is the general feeling of the medical authorities +that the direct blast effects were not great. Many of the Japanese +reports, which are believed to be false, describe immediate effects such as +ruptured abdomens with protruding intestines and protruding eyes, but no +such results were actually traced to the effect of air pressure alone. + + + +RADIATION INJURIES + + +As pointed out in another section of this report the radiations from the +nuclear explosions which caused injuries to persons were primarily those +experienced within the first second after the explosion; a few may have +occurred later, but all occurred in the first minute. The other two +general types of radiation, viz., radiation from scattered fission products +and induced radioactivity from objects near the center of explosion, were +definitely proved not to have caused any casualties. + +The proper designation of radiation injuries is somewhat difficult. +Probably the two most direct designations are radiation injury and gamma +ray injury. The former term is not entirely suitable in that it does not +define the type of radiation as ionizing and allows possible confusion with +other types of radiation (e.g., infra-red). The objection to the latter +term is that it limits the ionizing radiation to gamma rays, which were +undoubtedly the most important; but the possible contribution of neutron +and even beta rays to the biological effects cannot be entirely ignored. +Radiation injury has the advantage of custom, since it is generally +understood in medicine to refer to X-ray effect as distinguished from the +effects of actinic radiation. Accordingly, radiation injury is used in +this report to mean injury due only to ionizing radiation. + +According to Japanese observations, the early symptons in patients +suffering from radiation injury closely resembled the symptons observed in +patients receiving intensive roentgen therapy, as well as those observed in +experimental animals receiving large doses of X-rays. The important +symptoms reported by the Japanese and observed by American authorities were +epilation (lose of hair), petechiae (bleeding into the skin), and other +hemorrhagic manifestations, oropharyngeal lesions (inflammation of the +mouth and throat), vomiting, diarrhea, and fever. + +Epilation was one of the most spectacular and obvious findings. The +appearance of the epilated patient was typical. The crown was involved +more than the sides, and in many instances the resemblance to a monk's +tonsure was striking. In extreme cases the hair was totally lost. In some +cases, re-growth of hair had begun by the time patients were seen 50 days +after the bombing. Curiously, epilation of hair other than that of the +scalp was extremely unusual. + +Petechiae and other hemorrhagic manifestations were striking findings. +Bleeding began usually from the gums and in the more seriously affected was +soon evident from every possible source. Petechiae appeared on the limbs +and on pressure points. Large ecchymoses (hemorrhages under the skin) +developed about needle punctures, and wounds partially healed broke down +and bled freely. Retinal hemorrhages occurred in many of the patients. +The bleeding time and the coagulation time were prolonged. The platelets +(coagulation of the blood) were characteristically reduced in numbers. + +Nausea and vomiting appearing within a few hours after the explosion was +reported frequently by the Japanese. This usually had subsided by the +following morning, although occasionally it continued for two or three +days. Vomiting was not infrequently reported and observed during the +course of the later symptoms, although at these times it generally appeared +to be related to other manifestation of systemic reactions associated with +infection. + +Diarrhea of varying degrees of severity was reported and observed. In the +more severe cases, it was frequently bloody. For reasons which are not yet +clear, the diarrhea in some cases was very persistent. + +Lesions of the gums, and the oral mucous membrane, and the throat were +observed. The affected areas became deep red, then violacious in color; +and in many instances ulcerations and necrosis (breakdown of tissue) +followed. Blood counts done and recorded by the Japanese, as well as +counts done by the Manhattan Engineer District Group, on such patients +regularly showed leucopenia (low-white blood cell count). In extreme cases +the white blood cell count was below 1,000 (normal count is around 7,000). +In association with the leucopenia and the oropharyngeal lesions, a variety +of other infective processes were seen. Wounds and burns which were +healing adequately suppurated and serious necrosis occurred. At the same +time, similar ulcerations were observed in the larynx, bowels, and in +females, the gentalia. Fever usually accompanied these lesions. + +Eye injuries produced by the atomic bombings in both cities were the +subject of special investigations. The usual types of mechanical injuries +were seen. In addition, lesions consisting of retinal hemorrhage and +exudation were observed and 75% of the patients showing them had other +signs of radiation injury. + +The progress of radiation disease of various degrees of severity is shown +in the following table: + + Summary of Radiation Injury + Clinical Symptoms and Findings + +Day +after +Explo- +sion Most Severe Moderately Severe Mild + 1. 1. Nausea and vomiting 1. Nausea and vomiting + 2. after 1-2 hours. after 1-2 hours. + 3. NO DEFINITE SYMPTOMS + 4. + 5. 2. Diarrhea + 6. 3. Vomiting NO DEFINITE SYMPTOMS + 7. 4. Inflammation of the + mouth and throat + 8. 5. Fever + 9. 6. Rapid emaciation + 10. Death NO DEFINITE SYMPTOMS + 11. (Mortality probably 2. Beginning epilation. + 12. 100%) + 13. + 14. + 15. + 16. + 17. + 18. 3. Loss of appetite + 19. and general malaise. 1. Epilation + 20. 4. Fever. 2. Loss of appetite + 21. 5. Severe inflammation and malaise. + 22. of the mouth and throat 3. Sore throat. + 23. 4. Pallor. + 24. 5. Petechiae + 25. 6. Diarrhea + 26. 7. Moderate emacia- + 27. 6. Pallor. tion. + 28. 7. Petechiae, diarrhea + 29. and nose bleeds (Recovery unless com- + 30. plicated by previous + 31. 8. Rapid emaciation poor health or + Death super-imposed in- + (Mortality probably 50%) juries or infec- + tion). + +It was concluded that persons exposed to the bombs at the time of +detonation did show effects from ionizing radiation and that some of these +patients, otherwise uninjured, died. Deaths from radiation began about a +week after exposure and reached a peak in 3 to 4 weeks. They practically +ceased to occur after 7 to 8 weeks. + +Treatment of the burns and other physical injuries was carried out by the +Japanese by orthodox methods. Treatment of radiation effects by them +included general supportative measures such as rest and high vitamin and +caloric diets. Liver and calcium preparations were administered by +injection and blood transfusions were used to combat hemorrhage. Special +vitamin preparations and other special drugs used in the treatment of +similar medical conditions were used by American Army Medical Corps +officers after their arrival. Although the general measures instituted +were of some benefit no definite effect of any of the specific measures on +the course of the disease could be demonstrated. The use of sulfonamide +drugs by the Japanese and particularly of penicillin by the American +physicians after their arrival undoubtedly helped control the infections +and they appear to be the single important type of treatment which may have +effectively altered the earlier course of these patients. + +One of the most important tasks assigned to the mission which investigated +the effects of the bombing was that of determining if the radiation effects +were all due to the instantaneous discharges at the time of the explosion, +or if people were being harmed in addition from persistent radioactivity. +This question was investigated from two points of view. Direct +measurements of persistent radioactivity were made at the time of the +investigation. From these measurements, calculations were made of the +graded radiation dosages, i.e., the total amount of radiation which could +have been absorbed by any person. These calculations showed that the +highest dosage which would have been received from persistent radioactivity +at Hiroshima was between 6 and 25 roentgens of gamma radiation; the highest +in the Nagasaki Area was between 30 and 110 roentgens of gamma radiation. +The latter figure does not refer to the city itself, but to a localized +area in the Nishiyama District. In interpreting these findings it must be +understood that to get these dosages, one would have had to remain at the +point of highest radioactivity for 6 weeks continuously, from the first +hour after the bombing. It is apparent therefore that insofar as could be +determined at Hiroshima and Nagasaki, the residual radiation alone could +not have been detrimental to the health of persons entering and living in +the bombed areas after the explosion. + +The second approach to this question was to determine if any persons not in +the city at the time of the explosion, but coming in immediately afterwards +exhibited any symptoms or findings which might have been due to persistence +induced radioactivity. By the time of the arrival of the Manhattan +Engineer District group, several Japanese studies had been done on such +persons. None of the persons examined in any of these studies showed any +symptoms which could be attributed to radiation, and their actual blood +cell counts were consistently within the normal range. Throughout the +period of the Manhattan Engineer District investigation, Japanese doctors +and patients were repeatedly requested to bring to them any patients who +they thought might be examples of persons harmed from persistent +radioactivity. No such subjects were found. + +It was concluded therefore as a result of these findings and lack of +findings, that although a measurable quantity of induced radioactivity was +found, it had not been sufficient to cause any harm to persons living in +the two cities after the bombings. + + + +SHIELDING FROM RADIATION + + +Exact figures on the thicknesses of various substances to provide complete +or partial protection from the effects of radiation in relation to the +distance from the center of explosion, cannot be released at this time. +Studies of collected data are still under way. It can be stated, however, +that at a reasonable distance, say about 1/2 mile from the center of +explosion, protection to persons from radiation injury can be afforded by a +layer of concrete or other material whose thickness does not preclude +reasonable construction. + +Radiation ultimately caused the death of the few persons not killed by +other effects and who were fully exposed to the bombs up to a distance of +about 1/2 mile from X. The British Mission has estimated that people in +the open had a 50% chance of surviving the effects of radiation at 3/4 of a +mile from X. + + + +EFFECTS OF THE ATOMIC BOMBINGS ON THE INHABITANTS OF THE BOMBED CITIES + + +In both Hiroshima and Nagasaki the tremendous scale of the disaster largely +destroyed the cities as entities. Even the worst of all other previous +bombing attacks on Germany and Japan, such as the incendiary raids on +Hamburg in 1943 and on Tokyo in 1945, were not comparable to the paralyzing +effect of the atomic bombs. In addition to the huge number of persons who +were killed or injuried so that their services in rehabilitation were not +available, a panic flight of the population took place from both cities +immediately following the atomic explosions. No significant reconstruction +or repair work was accomplished because of the slow return of the +population; at the end of November 1945 each of the cities had only about +140,000 people. Although the ending of the war almost immediately after +the atomic bombings removed much of the incentive of the Japanese people +toward immediate reconstruction of their losses, their paralysis was still +remarkable. Even the clearance of wreckage and the burning of the many +bodies trapped in it were not well organized some weeks after the bombings. +As the British Mission has stated, "the impression which both cities make +is of having sunk, in an instant and without a struggle, to the most +primitive level." + +Aside from physical injury and damage, the most significant effect of the +atomic bombs was the sheer terror which it struck into the peoples of the +bombed cities. This terror, resulting in immediate hysterical activity and +flight from the cities, had one especially pronounced effect: persons who +had become accustomed to mass air raids had grown to pay little heed to +single planes or small groups of planes, but after the atomic bombings the +appearance of a single plane caused more terror and disruption of normal +life than the appearance of many hundreds of planes had ever been able to +cause before. The effect of this terrible fear of the potential danger +from even a single enemy plane on the lives of the peoples of the world in +the event of any future war can easily be conjectured. + +The atomic bomb did not alone win the war against Japan, but it most +certainly ended it, saving the thousands of Allied lives that would have +been lost in any combat invasion of Japan. + + + +EYEWITNESS ACCOUNT + Hiroshima -- August 6th, 1945 + +by Father John A. Siemes, professor of modern philosphy at Tokyo's Catholic +University + + +Up to August 6th, occasional bombs, which did no great damage, had fallen +on Hiroshima. Many cities roundabout, one after the other, were destroyed, +but Hiroshima itself remained protected. There were almost daily +observation planes over the city but none of them dropped a bomb. The +citizens wondered why they alone had remained undisturbed for so long a +time. There were fantastic rumors that the enemy had something special in +mind for this city, but no one dreamed that the end would come in such a +fashion as on the morning of August 6th. + +August 6th began in a bright, clear, summer morning. About seven o'clock, +there was an air raid alarm which we had heard almost every day and a few +planes appeared over the city. No one paid any attention and at about +eight o'clock, the all-clear was sounded. I am sitting in my room at the +Novitiate of the Society of Jesus in Nagatsuke; during the past half year, +the philosophical and theological section of our Mission had been evacuated +to this place from Tokyo. The Novitiate is situated approximately two +kilometers from Hiroshima, half-way up the sides of a broad valley which +stretches from the town at sea level into this mountainous hinterland, and +through which courses a river. From my window, I have a wonderful view +down the valley to the edge of the city. + +Suddenly--the time is approximately 8:14--the whole valley is filled by a +garish light which resembles the magnesium light used in photography, and I +am conscious of a wave of heat. I jump to the window to find out the cause +of this remarkable phenomenon, but I see nothing more than that brilliant +yellow light. As I make for the door, it doesn't occur to me that the +light might have something to do with enemy planes. On the way from the +window, I hear a moderately loud explosion which seems to come from a +distance and, at the same time, the windows are broken in with a loud +crash. There has been an interval of perhaps ten seconds since the flash +of light. I am sprayed by fragments of glass. The entire window frame has +been forced into the room. I realize now that a bomb has burst and I am +under the impression that it exploded directly over our house or in the +immediate vicinity. + +I am bleeding from cuts about the hands and head. I attempt to get out of +the door. It has been forced outwards by the air pressure and has become +jammed. I force an opening in the door by means of repeated blows with my +hands and feet and come to a broad hallway from which open the various +rooms. Everything is in a state of confusion. All windows are broken and +all the doors are forced inwards. The bookshelves in the hallway have +tumbled down. I do not note a second explosion and the fliers seem to have +gone on. Most of my colleagues have been injured by fragments of glass. A +few are bleeding but none has been seriously injured. All of us have been +fortunate since it is now apparent that the wall of my room opposite the +window has been lacerated by long fragments of glass. + +We proceed to the front of the house to see where the bomb has landed. +There is no evidence, however, of a bomb crater; but the southeast section +of the house is very severely damaged. Not a door nor a window remains. +The blast of air had penetrated the entire house from the southeast, but +the house still stands. It is constructed in a Japanese style with a +wooden framework, but has been greatly strengthened by the labor of our +Brother Gropper as is frequently done in Japanese homes. Only along the +front of the chapel which adjoins the house, three supports have given way +(it has been made in the manner of Japanese temple, entirely out of wood.) + +Down in the valley, perhaps one kilometer toward the city from us, several +peasant homes are on fire and the woods on the opposite side of the valley +are aflame. A few of us go over to help control the flames. While we are +attempting to put things in order, a storm comes up and it begins to rain. +Over the city, clouds of smoke are rising and I hear a few slight +explosions. I come to the conclusion that an incendiary bomb with an +especially strong explosive action has gone off down in the valley. A few +of us saw three planes at great altitude over the city at the time of the +explosion. I, myself, saw no aircraft whatsoever. + +Perhaps a half-hour after the explosion, a procession of people begins to +stream up the valley from the city. The crowd thickens continuously. A +few come up the road to our house. We give them first aid and bring them +into the chapel, which we have in the meantime cleaned and cleared of +wreckage, and put them to rest on the straw mats which constitute the floor +of Japanese houses. A few display horrible wounds of the extremities and +back. The small quantity of fat which we possessed during this time of war +was soon used up in the care of the burns. Father Rektor who, before +taking holy orders, had studied medicine, ministers to the injured, but our +bandages and drugs are soon gone. We must be content with cleansing the +wounds. + +More and more of the injured come to us. The least injured drag the more +seriously wounded. There are wounded soldiers, and mothers carrying burned +children in their arms. From the houses of the farmers in the valley comes +word: "Our houses are full of wounded and dying. Can you help, at least by +taking the worst cases?" The wounded come from the sections at the edge of +the city. They saw the bright light, their houses collapsed and buried the +inmates in their rooms. Those that were in the open suffered instantaneous +burns, particularly on the lightly clothed or unclothed parts of the body. +Numerous fires sprang up which soon consumed the entire district. We now +conclude that the epicenter of the explosion was at the edge of the city +near the Jokogawa Station, three kilometers away from us. We are concerned +about Father Kopp who that same morning, went to hold Mass at the Sisters +of the Poor, who have a home for children at the edge of the city. He had +not returned as yet. + +Toward noon, our large chapel and library are filled with the seriously +injured. The procession of refugees from the city continues. Finally, +about one o'clock, Father Kopp returns, together with the Sisters. Their +house and the entire district where they live has burned to the ground. +Father Kopp is bleeding about the head and neck, and he has a large burn on +the right palm. He was standing in front of the nunnery ready to go home. +All of a sudden, he became aware of the light, felt the wave of heat and a +large blister formed on his hand. The windows were torn out by the blast. +He thought that the bomb had fallen in his immediate vicinity. The +nunnery, also a wooden structure made by our Brother Gropper, still +remained but soon it is noted that the house is as good as lost because the +fire, which had begun at many points in the neighborhood, sweeps closer and +closer, and water is not available. There is still time to rescue certain +things from the house and to bury them in an open spot. Then the house is +swept by flame, and they fight their way back to us along the shore of the +river and through the burning streets. + +Soon comes news that the entire city has been destroyed by the explosion +and that it is on fire. What became of Father Superior and the three other +Fathers who were at the center of the city at the Central Mission and +Parish House? We had up to this time not given them a thought because we +did not believe that the effects of the bomb encompassed the entire city. +Also, we did not want to go into town except under pressure of dire +necessity, because we thought that the population was greatly perturbed and +that it might take revenge on any foreigners which they might consider +spiteful onlookers of their misfortune, or even spies. + +Father Stolte and Father Erlinghagen go down to the road which is still +full of refugees and bring in the seriously injured who have sunken by the +wayside, to the temporary aid station at the village school. There iodine +is applied to the wounds but they are left uncleansed. Neither ointments +nor other therapeutic agents are available. Those that have been brought +in are laid on the floor and no one can give them any further care. What +could one do when all means are lacking? Under those circumstances, it is +almost useless to bring them in. Among the passersby, there are many who +are uninjured. In a purposeless, insensate manner, distraught by the +magnitude of the disaster most of them rush by and none conceives the +thought of organizing help on his own initiative. They are concerned only +with the welfare of their own families. It became clear to us during these +days that the Japanese displayed little initiative, preparedness, and +organizational skill in preparation for catastrophes. They failed to carry +out any rescue work when something could have been saved by a cooperative +effort, and fatalistically let the catastrophe take its course. When we +urged them to take part in the rescue work, they did everything willingly, +but on their own initiative they did very little. + +At about four o'clock in the afternoon, a theology student and two +kindergarten children, who lived at the Parish House and adjoining +buildings which had burned down, came in and said that Father Superior +LaSalle and Father Schiffer had been seriously injured and that they had +taken refuge in Asano Park on the river bank. It is obvious that we must +bring them in since they are too weak to come here on foot. + +Hurriedly, we get together two stretchers and seven of us rush toward the +city. Father Rektor comes along with food and medicine. The closer we get +to the city, the greater is the evidence of destruction and the more +difficult it is to make our way. The houses at the edge of the city are +all severely damaged. Many have collapsed or burned down. Further in, +almost all of the dwellings have been damaged by fire. Where the city +stood, there is a gigantic burned-out scar. We make our way along the +street on the river bank among the burning and smoking ruins. Twice we are +forced into the river itself by the heat and smoke at the level of the +street. + +Frightfully burned people beckon to us. Along the way, there are many dead +and dying. On the Misasi Bridge, which leads into the inner city we are +met by a long procession of soldiers who have suffered burns. They drag +themselves along with the help of staves or are carried by their less +severely injured comrades...an endless procession of the unfortunate. + +Abandoned on the bridge, there stand with sunken heads a number of horses +with large burns on their flanks. On the far side, the cement structure of +the local hospital is the only building that remains standing. Its +interior, however, has been burned out. It acts as a landmark to guide us +on our way. + +Finally we reach the entrance of the park. A large proportion of the +populace has taken refuge there, but even the trees of the park are on fire +in several places. Paths and bridges are blocked by the trunks of fallen +trees and are almost impassable. We are told that a high wind, which may +well have resulted from the heat of the burning city, has uprooted the +large trees. It is now quite dark. Only the fires, which are still raging +in some places at a distance, give out a little light. + +At the far corner of the park, on the river bank itself, we at last come +upon our colleagues. Father Schiffer is on the ground pale as a ghost. He +has a deep incised wound behind the ear and has lost so much blood that we +are concerned about his chances for survival. The Father Superior has +suffered a deep wound of the lower leg. Father Cieslik and Father +Kleinsorge have minor injuries but are completely exhausted. + + +While they are eating the food that we have brought along, they tell us of +their experiences. They were in their rooms at the Parish House--it was a +quarter after eight, exactly the time when we had heard the explosion in +Nagatsuke--when came the intense light and immediately thereafter the sound +of breaking windows, walls and furniture. They were showered with glass +splinters and fragments of wreckage. Father Schiffer was buried beneath a +portion of a wall and suffered a severe head injury. The Father Superior +received most of the splinters in his back and lower extremity from which +he bled copiously. Everything was thrown about in the rooms themselves, +but the wooden framework of the house remained intact. The solidity of the +structure which was the work of Brother Gropper again shone forth. + +They had the same impression that we had in Nagatsuke: that the bomb had +burst in their immediate vicinity. The Church, school, and all buildings +in the immediate vicinity collapsed at once. Beneath the ruins of the +school, the children cried for help. They were freed with great effort. +Several others were also rescued from the ruins of nearby dwellings. Even +the Father Superior and Father Schiffer despite their wounds, rendered aid +to others and lost a great deal of blood in the process. + +In the meantime, fires which had begun some distance away are raging even +closer, so that it becomes obvious that everything would soon burn down. +Several objects are rescued from the Parish House and were buried in a +clearing in front of the Church, but certain valuables and necessities +which had been kept ready in case of fire could not be found on account of +the confusion which had been wrought. It is high time to flee, since the +oncoming flames leave almost no way open. Fukai, the secretary of the +Mission, is completely out of his mind. He does not want to leave the +house and explains that he does not want to survive the destruction of his +fatherland. He is completely uninjured. Father Kleinsorge drags him out +of the house on his back and he is forcefully carried away. + + +Beneath the wreckage of the houses along the way, many have been trapped +and they scream to be rescued from the oncoming flames. They must be left +to their fate. The way to the place in the city to which one desires to +flee is no longer open and one must make for Asano Park. Fukai does not +want to go further and remains behind. He has not been heard from since. +In the park, we take refuge on the bank of the river. A very violent +whirlwind now begins to uproot large trees, and lifts them high into the +air. As it reaches the water, a waterspout forms which is approximately +100 meters high. The violence of the storm luckily passes us by. Some +distance away, however, where numerous refugees have taken shelter, many +are blown into the river. Almost all who are in the vicinity have been +injured and have lost relatives who have been pinned under the wreckage or +who have been lost sight of during the flight. There is no help for the +wounded and some die. No one pays any attention to a dead man lying +nearby. + +The transportation of our own wounded is difficult. It is not possible to +dress their wounds properly in the darkness, and they bleed again upon +slight motion. As we carry them on the shaky litters in the dark over +fallen trees of the park, they suffer unbearable pain as the result of the +movement, and lose dangerously large quantities of blood. Our rescuing +angel in this difficult situation is a Japanese Protestant pastor. He has +brought up a boat and offers to take our wounded up stream to a place where +progress is easier. First, we lower the litter containing Father Schiffer +into the boat and two of us accompany him. We plan to bring the boat back +for the Father Superior. The boat returns about one-half hour later and +the pastor requests that several of us help in the rescue of two children +whom he had seen in the river. We rescue them. They have severe burns. +Soon they suffer chills and die in the park. + +The Father Superior is conveyed in the boat in the same manner as Father +Schiffer. The theology student and myself accompany him. Father Cieslik +considers himself strong enough to make his way on foot to Nagatsuke with +the rest of us, but Father Kleinsorge cannot walk so far and we leave him +behind and promise to come for him and the housekeeper tomorrow. From the +other side of the stream comes the whinny of horses who are threatened by +the fire. We land on a sand spit which juts out from the shore. It is +full of wounded who have taken refuge there. They scream for aid for they +are afraid of drowning as the river may rise with the sea, and cover the +sand spit. They themselves are too weak to move. However, we must press +on and finally we reach the spot where the group containing Father Schiffer +is waiting. + + +Here a rescue party had brought a large case of fresh rice cakes but there +is no one to distribute them to the numerous wounded that lie all about. +We distribute them to those that are nearby and also help ourselves. The +wounded call for water and we come to the aid of a few. Cries for help are +heard from a distance, but we cannot approach the ruins from which they +come. A group of soldiers comes along the road and their officer notices +that we speak a strange language. He at once draws his sword, screamingly +demands who we are and threatens to cut us down. Father Laures, Jr., +seizes his arm and explains that we are German. We finally quiet him down. +He thought that we might well be Americans who had parachuted down. Rumors +of parachutists were being bandied about the city. The Father Superior who +was clothed only in a shirt and trousers, complains of feeling freezing +cold, despite the warm summer night and the heat of the burning city. The +one man among us who possesses a coat gives it to him and, in addition, I +give him my own shirt. To me, it seems more comfortable to be without a +shirt in the heat. + +In the meantime, it has become midnight. Since there are not enough of us +to man both litters with four strong bearers, we determine to remove Father +Schiffer first to the outskirts of the city. From there, another group of +bearers is to take over to Nagatsuke; the others are to turn back in order +to rescue the Father Superior. I am one of the bearers. The theology +student goes in front to warn us of the numerous wires, beams and fragments +of ruins which block the way and which are impossible to see in the dark. +Despite all precautions, our progress is stumbling and our feet get tangled +in the wire. Father Kruer falls and carries the litter with him. Father +Schiffer becomes half unconscious from the fall and vomits. We pass an +injured man who sits all alone among the hot ruins and whom I had seen +previously on the way down. + +On the Misasa Bridge, we meet Father Tappe and Father Luhmer, who have come +to meet us from Nagatsuke. They had dug a family out of the ruins of their +collapsed house some fifty meters off the road. The father of the family +was already dead. They had dragged out two girls and placed them by the +side of the road. Their mother was still trapped under some beams. They +had planned to complete the rescue and then to press on to meet us. At the +outskirts of the city, we put down the litter and leave two men to wait +until those who are to come from Nagatsuke appear. The rest of us turn +back to fetch the Father Superior. + +Most of the ruins have now burned down. The darkness kindly hides the many +forms that lie on the ground. Only occasionally in our quick progress do +we hear calls for help. One of us remarks that the remarkable burned smell +reminds him of incinerated corpses. The upright, squatting form which we +had passed by previously is still there. + +Transportation on the litter, which has been constructed out of boards, +must be very painful to the Father Superior, whose entire back is full of +fragments of glass. In a narrow passage at the edge of town, a car forces +us to the edge of the road. The litter bearers on the left side fall into +a two meter deep ditch which they could not see in the darkness. Father +Superior hides his pain with a dry joke, but the litter which is now no +longer in one piece cannot be carried further. We decide to wait until +Kinjo can bring a hand cart from Nagatsuke. He soon comes back with one +that he has requisitioned from a collapsed house. We place Father Superior +on the cart and wheel him the rest of the way, avoiding as much as possible +the deeper pits in the road. + +About half past four in the morning, we finally arrive at the Novitiate. +Our rescue expedition had taken almost twelve hours. Normally, one could +go back and forth to the city in two hours. Our two wounded were now, for +the first time, properly dressed. I get two hours sleep on the floor; some +one else has taken my own bed. Then I read a Mass in gratiarum actionem, +it is the 7th of August, the anniversary of the foundation of our society. +Then we bestir ourselves to bring Father Kleinsorge and other acquaintances +out of the city. + + +We take off again with the hand cart. The bright day now reveals the +frightful picture which last night's darkness had partly concealed. Where +the city stood everything, as far as the eye could reach, is a waste of +ashes and ruin. Only several skeletons of buildings completely burned out +in the interior remain. The banks of the river are covered with dead and +wounded, and the rising waters have here and there covered some of the +corpses. On the broad street in the Hakushima district, naked burned +cadavers are particularly numerous. Among them are the wounded who are +still alive. A few have crawled under the burnt-out autos and trams. +Frightfully injured forms beckon to us and then collapse. An old woman and +a girl whom she is pulling along with her fall down at our feet. We place +them on our cart and wheel them to the hospital at whose entrance a +dressing station has been set up. Here the wounded lie on the hard floor, +row on row. Only the largest wounds are dressed. We convey another +soldier and an old woman to the place but we cannot move everybody who lies +exposed in the sun. It would be endless and it is questionable whether +those whom we can drag to the dressing station can come out alive, because +even here nothing really effective can be done. Later, we ascertain that +the wounded lay for days in the burnt-out hallways of the hospital and +there they died. + +We must proceed to our goal in the park and are forced to leave the wounded +to their fate. We make our way to the place where our church stood to dig +up those few belongings that we had buried yesterday. We find them intact. +Everything else has been completely burned. In the ruins, we find a few +molten remnants of holy vessels. At the park, we load the housekeeper and +a mother with her two children on the cart. Father Kleinsorge feels strong +enough, with the aid of Brother Nobuhara, to make his way home on foot. +The way back takes us once again past the dead and wounded in Hakushima. +Again no rescue parties are in evidence. At the Misasa Bridge, there still +lies the family which the Fathers Tappe and Luhmer had yesterday rescued +from the ruins. A piece of tin had been placed over them to shield them +from the sun. We cannot take them along for our cart is full. We give +them and those nearby water to drink and decide to rescue them later. At +three o'clock in the afternoon, we are back in Nagatsuka. + +After we have had a few swallows and a little food, Fathers Stolte, Luhmer, +Erlinghagen and myself, take off once again to bring in the family. Father +Kleinsorge requests that we also rescue two children who had lost their +mother and who had lain near him in the park. On the way, we were greeted +by strangers who had noted that we were on a mission of mercy and who +praised our efforts. We now met groups of individuals who were carrying +the wounded about on litters. As we arrived at the Misasa Bridge, the +family that had been there was gone. They might well have been borne away +in the meantime. There was a group of soldiers at work taking away those +that had been sacrificed yesterday. + + +More than thirty hours had gone by until the first official rescue party +had appeared on the scene. We find both children and take them out of the +park: a six-year old boy who was uninjured, and a twelve-year old girl who +had been burned about the head, hands and legs, and who had lain for thirty +hours without care in the park. The left side of her face and the left eye +were completely covered with blood and pus, so that we thought that she had +lost the eye. When the wound was later washed, we noted that the eye was +intact and that the lids had just become stuck together. On the way home, +we took another group of three refugees with us. They first wanted to +know, however, of what nationality we were. They, too, feared that we +might be Americans who had parachuted in. When we arrived in Nagatsuka, it +had just become dark. + +We took under our care fifty refugees who had lost everything. The +majority of them were wounded and not a few had dangerous burns. Father +Rektor treated the wounds as well as he could with the few medicaments that +we could, with effort, gather up. He had to confine himself in general to +cleansing the wounds of purulent material. Even those with the smaller +burns are very weak and all suffered from diarrhea. In the farm houses in +the vicinity, almost everywhere, there are also wounded. Father Rektor +made daily rounds and acted in the capacity of a painstaking physician and +was a great Samaritan. Our work was, in the eyes of the people, a greater +boost for Christianity than all our work during the preceding long years. + +Three of the severely burned in our house died within the next few days. +Suddenly the pulse and respirations ceased. It is certainly a sign of our +good care that so few died. In the official aid stations and hospitals, a +good third or half of those that had been brought in died. They lay about +there almost without care, and a very high percentage succumbed. +Everything was lacking: doctors, assistants, dressings, drugs, etc. In an +aid station at a school at a nearby village, a group of soldiers for +several days did nothing except to bring in and cremate the dead behind the +school. + + +During the next few days, funeral processions passed our house from morning +to night, bringing the deceased to a small valley nearby. There, in six +places, the dead were burned. People brought their own wood and themselves +did the cremation. Father Luhmer and Father Laures found a dead man in a +nearby house who had already become bloated and who emitted a frightful +odor. They brought him to this valley and incinerated him themselves. +Even late at night, the little valley was lit up by the funeral pyres. + +We made systematic efforts to trace our acquaintances and the families of +the refugees whom we had sheltered. Frequently, after the passage of +several weeks, some one was found in a distant village or hospital but of +many there was no news, and these were apparently dead. We were lucky to +discover the mother of the two children whom we had found in the park and +who had been given up for dead. After three weeks, she saw her children +once again. In the great joy of the reunion were mingled the tears for +those whom we shall not see again. + + +The magnitude of the disaster that befell Hiroshima on August 6th was only +slowly pieced together in my mind. I lived through the catastrophe and saw +it only in flashes, which only gradually were merged to give me a total +picture. What actually happened simultaneously in the city as a whole is +as follows: As a result of the explosion of the bomb at 8:15, almost the +entire city was destroyed at a single blow. Only small outlying districts +in the southern and eastern parts of the town escaped complete destruction. +The bomb exploded over the center of the city. As a result of the blast, +the small Japanese houses in a diameter of five kilometers, which +compressed 99% of the city, collapsed or were blown up. Those who were in +the houses were buried in the ruins. Those who were in the open sustained +burns resulting from contact with the substance or rays emitted by the +bomb. Where the substance struck in quantity, fires sprang up. These +spread rapidly. + +The heat which rose from the center created a whirlwind which was effective +in spreading fire throughout the whole city. Those who had been caught +beneath the ruins and who could not be freed rapidly, and those who had +been caught by the flames, became casualties. As much as six kilometers +from the center of the explosion, all houses were damaged and many +collapsed and caught fire. Even fifteen kilometers away, windows were +broken. It was rumored that the enemy fliers had spread an explosive and +incendiary material over the city and then had created the explosion and +ignition. A few maintained that they saw the planes drop a parachute which +had carried something that exploded at a height of 1,000 meters. The +newspapers called the bomb an "atomic bomb" and noted that the force of the +blast had resulted from the explosion of uranium atoms, and that gamma rays +had been sent out as a result of this, but no one knew anything for certain +concerning the nature of the bomb. + +How many people were a sacrifice to this bomb? Those who had lived through +the catastrophe placed the number of dead at at least 100,000. Hiroshima +had a population of 400,000. Official statistics place the number who had +died at 70,000 up to September 1st, not counting the missing ... and +130,000 wounded, among them 43,500 severely wounded. Estimates made by +ourselves on the basis of groups known to us show that the number of +100,000 dead is not too high. Near us there are two barracks, in each of +which forty Korean workers lived. On the day of the explosion, they were +laboring on the streets of Hiroshima. Four returned alive to one barracks +and sixteen to the other. 600 students of the Protestant girls' school +worked in a factory, from which only thirty to forty returned. Most of the +peasant families in the neighborhood lost one or more of their members who +had worked at factories in the city. Our next door neighbor, Tamura, lost +two children and himself suffered a large wound since, as it happened, he +had been in the city on that day. The family of our reader suffered two +dead, father and son; thus a family of five members suffered at least two +losses, counting only the dead and severely wounded. There died the Mayor, +the President of the central Japan district, the Commander of the city, a +Korean prince who had been stationed in Hiroshima in the capacity of an +officer, and many other high ranking officers. Of the professors of the +University, thirty-two were killed or severely injured. Especially hard +hit were the soldiers. The Pioneer Regiment was almost entirely wiped out. +The barracks were near the center of the explosion. + +Thousands of wounded who died later could doubtless have been rescued had +they received proper treatment and care, but rescue work in a catastrophe +of this magnitude had not been envisioned; since the whole city had been +knocked out at a blow, everything which had been prepared for emergency +work was lost, and no preparation had been made for rescue work in the +outlying districts. Many of the wounded also died because they had been +weakened by under-nourishment and consequently lacked in strength to +recover. Those who had their normal strength and who received good care +slowly healed the burns which had been occasioned by the bomb. There were +also cases, however, whose prognosis seemed good who died suddenly. There +were also some who had only small external wounds who died within a week or +later, after an inflammation of the pharynx and oral cavity had taken +place. We thought at first that this was the result of inhalation of the +substance of the bomb. Later, a commission established the thesis that +gamma rays had been given out at the time of the explosion, following which +the internal organs had been injured in a manner resembling that consequent +upon Roentgen irradiation. This produces a diminution in the numbers of +the white corpuscles. + +Only several cases are known to me personally where individuals who did not +have external burns later died. Father Kleinsorge and Father Cieslik, who +were near the center of the explosion, but who did not suffer burns became +quite weak some fourteen days after the explosion. Up to this time small +incised wounds had healed normally, but thereafter the wounds which were +still unhealed became worse and are to date (in September) still +incompletely healed. The attending physician diagnosed it as leucopania. +There thus seems to be some truth in the statement that the radiation had +some effect on the blood. I am of the opinion, however, that their +generally undernourished and weakened condition was partly responsible for +these findings. It was noised about that the ruins of the city emitted +deadly rays and that workers who went there to aid in the clearing died, +and that the central district would be uninhabitable for some time to come. +I have my doubts as to whether such talk is true and myself and others who +worked in the ruined area for some hours shortly after the explosion +suffered no such ill effects. + +None of us in those days heard a single outburst against the Americans on +the part of the Japanese, nor was there any evidence of a vengeful spirit. +The Japanese suffered this terrible blow as part of the fortunes of war ... +something to be borne without complaint. During this, war, I have noted +relatively little hatred toward the allies on the part of the people +themselves, although the press has taken occasion to stir up such feelings. +After the victories at the beginning of the war, the enemy was rather +looked down upon, but when allied offensive gathered momentum and +especially after the advent of the majestic B-29's, the technical skill of +America became an object of wonder and admiration. + +The following anecdote indicates the spirit of the Japanese: A few days +after the atomic bombing, the secretary of the University came to us +asserting that the Japanese were ready to destroy San Francisco by means of +an equally effective bomb. It is dubious that he himself believed what he +told us. He merely wanted to impress upon us foreigners that the Japanese +were capable of similar discoveries. In his nationalistic pride, he talked +himself into believing this. The Japanese also intimated that the +principle of the new bomb was a Japanese discovery. It was only lack of +raw materials, they said, which prevented its construction. In the +meantime, the Germans were said to have carried the discovery to a further +stage and were about to initiate such bombing. The Americans were reputed +to have learned the secret from the Germans, and they had then brought the +bomb to a stage of industrial completion. + + +We have discussed among ourselves the ethics of the use of the bomb. Some +consider it in the same category as poison gas and were against its use on +a civil population. Others were of the view that in total war, as carried +on in Japan, there was no difference between civilians and soldiers, and +that the bomb itself was an effective force tending to end the bloodshed, +warning Japan to surrender and thus to avoid total destruction. It seems +logical to me that he who supports total war in principle cannot complain +of war against civilians. The crux of the matter is whether total war in +its present form is justifiable, even when it serves a just purpose. Does +it not have material and spiritual evil as its consequences which far +exceed whatever good that might result? When will our moralists give us a +clear answer to this question? + + + + + +End of Project Gutenberg's Etext of A-Bombing of Hiroshima and Nagasaki + diff --git a/old/abomb10.zip b/old/abomb10.zip Binary files differnew file mode 100644 index 0000000..113754c --- /dev/null +++ b/old/abomb10.zip |