Introduction Ow Manca 1, 1954, an experimental thermonuclear device was exploded at the U.S. Atomic Energy Commission's Eniwetok Proving structure deposited radioactive materials on inhabited atolls and on ships of Jcint Task Force #7, which was conducting the tests. ous radiation levels; therefore, evacuation was cies in the field enabled the medical team to rollowing the detonation, unexpected changes in the wind Radiation surveys of the areas revealed injuri- ordered, and was carried out as quickly as pos- sible with the facilities available to the Task Force. Although the calculated accumulated doses to the exposed human beings were believed to be well below levels that would produce serious injury or any mortality, the (‘commander of the Task Force requested the Department of De- fense and the U. S. Atomic Energy Commission to organize a medical team tu provide the best possible care of the exposed persons and to make a medical study of the exposures. Responsibility for organization of the medical team was shared by the Armed Forces Special Weapons Project, Department of Defense, and the Division of Biology and Medicine, U.S. Atomic Energy Commission. Experienced professional and technical personnel were immediately available from the Naval Medical Research Institute and the U.S. Naval Radiologi- ee U.S. Naval Station, Kwajalein, Marshall Is- lands The commander of the ravalstation had arranged living facilities for the exposed Marshallese, and installed laboratory and clinical facilities as requested immediately upon arrival of the medical team. (rounds in the Marshal! Islands. meeeee Interim care and study had been capably handied by the smal! medical department of the cal Defense Laboratory. Since speed was es- Sential in the organization and transport of the medical team to the mid-Pacific area, the as- sistance of the Medical Department of the Navy was requested. and was promptly received from the Surgeon General. A team was organized from. personnel of the two Navylaboratories and representatives of the AEC Division of Biology and Medicine and the Armed Forces Special Weapons Project. The team was air lifted to the Marshall J-'ands, arriving on the eighth day after the explosion. - Full cooperation and support from all agen- operate at maximum efficiency, so that the degree of radiation injury could be assessed quickly, and appropriate care and study of the injured could be instituted without delay. All of the exposed individuals have recovered from the immediate effects without serious sequelae. Nevertheless it is planned to evaluate the medical and genetic status of the group at appropriate intervals with a view to learning what if any of the known late effects of radia- tion exposure may be observed. Obviously and indeed fortunately the number of persons re- ceiving 75 roentgens exposure and greater is too small to make it possible to determine with any degree of accuracy the effect on life span. In addition to providing medical care for these persons, the teain accumulated a large body of scientific observations on radiation injury in human beings. The initial data have been supplemented by field resurveys 6, and 24 months after the original investigation. The results of this work are summarized in the present volume. The data which were ob- tained substantially increase the fundamental knowledge of radiation tnjury and the medical capability of caring for persons exposed to large doses of radiation. Cirakves F. Dunuaw. M.D. Director, Division of Biology and Medicine, U.S. Atomic Energy Commission.

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