ファーレル米軍准将広島調査結果声明
１９４５年９月１２日
STATEMENT BY BRIG. F. FARELL
CHIEF, ATOMIC BOMB MISSION
Tokyo, Japan
12th September 1945
We have made a preliminary inspection of Hiroshima. Our doctors stayed over in Hiroshima, in order to make a further study of those injured by the explosion of the atomic bomb. Detailed studies of the effects, both physical and on personnel, will be continued in order that we may have a true picture of the results of the explosion.
Detailed measurements of the city were made by our scientific personnel to determine if there was any radio activity present. No measurable radio activity was found under the point of detonation or elsewhere on the ground, streets, in the ashes, or on other materials. Col. Stafford Warren, Medical Corps, of Rochester, N. Y., who has been the chief Medical Officer of the project for the past three years and who is an expert in the field of radiology, has made a preliminary check on the casualties. These investigations will continue.
Col. Warren’s preliminary conclusions are as follows:-
The largest number of casualties at Hiroshima probably resulted from blasts, missles and fires. The actual numbers and proportions will probably never be known. Many, of course, will die from the initial effects of the explosion.
Colonel Warren and his party of doctors have examined a number of patients whose symptoms are such as would be caused by radiation. It is Col. Warren’s opinion that those patients who were affected by radiation resulted from a single exposure to a dose of gamma radiation at the time of detonation, and that they did not result from the deposit of dangerous amounts of radio activity on the ground. His conclusions are based on the information obtained as to locations of the affected individuals at the time of the blast, and on the results from the New Mexico test as related to the detonation at Hiroshima. It is believed by Colonel Warren that the much higher altitude of detonation would prevent the deposit of much radio activity on the ground and, at the same time, would increase the blast effects of the weapon. Persons could survive the blast, missles, or flames, and still be within the comparatively limited range of the gamma radiation at the time of the explosion. Some of them could have been shielded by buildings or other obstructions from the effects of the blast and heat. The bomb was designed primarily as a blast weapon, with secondary effects from heat and light and, at the elevation used, it was expected that there would be a radio active effect in a limited area under the point of detonation just at the moment of the explosion. It was further expected that any one so affected would have received serious damage from the primary effects of the bomb. Many of the patients examined by Colonel Warren who showed results of radio active damage also had either burns or other injuries.
The story that personnel coming into the area to assist in evacuation were seriously injured is the truth, but not the whole truth. The personnel were already in the area to carry out a previously ordered evacuation and were caught there by the blast. Many of them became casualties. Some other personnel, mostly military, arrived in the area about ten hours after the explosion. Statement have been made by the Japanese that these showed ill effects, including fatigue. Japanese officials at Hiroshima on 9 September stated that none of these died and none were seriously affected. This confirms the opinion of our experts that there would be no residual radioactivity on the ground in dangerous amounts. At our meeting in Hiroshima, Dr. Masao Tsuzuki, radiologist at the Imperial University, made a statement that he considered it possible that poison gases were released at the time of the explosion of the bomb, and asked for confirmation or denial. An official statement was made to Dr. Tsuzuki that such an assumption was entirely erroneous. No poison gasses were released.
The Japanese have made an official report, dated 15 August, of their investigation of Hiroshima, largely by Medical Officers, and the following is quoted from an official U. S. translation of their report:- “At present (15 August 45), an increase in radioactivity in the area of explosion has been noted, but not to the extent that it will be injurious to humans. Immediately following the explosion, the amount of radioactive rays which caused human injuries could not be determined. Also, the actual presence of radioactive substances, and the assumption that artificial radioactive substances were created, could not be proved.”
We have no means of checking the radioactive conditions existing on the 15th of August, but we found none on the 9th of September. there was no crater. There was no sign of heating of the ground beyond that due to burning buildings. There was no fusing of the ground nor melting of materials such as occurred at New Mexico, where the bomb was set off at a much lower altitude. The area immediately under the point of detonation is not marked by any special phenomena on the ground, either physical or radio active.
The flash burning by radiant heat was quite spectacular. A cardboard sign at about 1-1/4 miles away had the black lettering charred and the white background untouched. In a building a mile away from the explosion, plush chairs in front of a window were scorched on the portions exposed to radiant heat coming through the window.
The physical destruction in the target area was practically complete. The scene was one of utter devastation. The number of totally burned buildings at Hiroshima was 55,000. The number half-burned was 2300; totally destroyed by blast 6800; half destroyed by blast 3800.
The total number destroyed and damaged buildings was 68,000, or somewhere between 80 and 90% of the entire buildings in the city. The above statistical information is from Hiroshima officials. For a radius of 1-1/4 miles from point of detonation, the area including the Japanese military headquarters was completely demolished. To a radius of two miles, everything is blasted with some burning. Between two and three miles, the buildings are about half destroyed. Beyond three miles, the damage is generally slight, with roof damage up to five miles and glass broken up to twelve miles. About twenty well built structures of masonry and steel remain standing in central portion of city, but all windows are out and interiors are gutted. A few bridges are destroyed but most modern bridges are intact expect for hand rails and some sidewalks which have torn loose. Individual warehouses are collapsed on the pier area, nearly three miles away. Relatively close areas were protected from the blast by intervening hills. Light shelters were caved in, street cars were derailed and burned, automobiles had the roofs caved in. A fire started in the forest on a mountain about four miles away.
Huge trees were uprooted and broken. The Japanese reported that of the 9,000 soldiers in Hiroshima, 4,000 were killed, 3,000 were wounded, and 2,000 escaped. The dead include the Commanding General and his entire staff.