a SKIN LESIONS AND EPILATION a. Shelter. Those individuals who remained indoors or under the trees during the fallout period developed less severe lesions. b. Bathing. Small children who went wading in the ocean developed fewer foot lesions. Most of the Americans, who were more aware of the danger of the fallout, took shelter in aluminum buildings, bathed and changed clothes and consequently developed only very mild beta lesions. c. Clothing. A single layer of cotton material offered almost complete protection, as was clemonstrated by the fact that lesions developed almost entirely on the exposed parts of the body. 3.54 Factors Favoring the Development of Lesions a. Areas of more profuse perspiration. Lesions were more numerous in areas where perspiration is abundantsuch as the folds of the veck, axillae, and antecubital fossae. b. Delay in decontumination. There was a delay of 1 or 2 days before satisfactory decon- tamination was possible. The prolonged contact of radioactive materials on the skin during this period incrensed the dose to the skin. However, the close rate fell off rapidly and de- contamination would have had to be promptin order to have been most effective. c. Difficulties in decontamination. The thick 35 3.7 Discussion Tuere Has Been little previous experience with radiation dermatitis resulting from exposure to fallout material from nuclear detonations, and the general consensus, until this event, has been that the hazard from fallout material was negligible. From the present experience it is evident that following detonationof a large seale device close to the ground, serious exposure of personnel with resulting radiation lesions of the skin may occur from fallout material, even at considerable distances from the site of detonation. This incidentis the first example of large numbers of radiation burns of human beings produced by exposure to fallout material. With the Hiroshima and Nagasaki detonations fallout was not a problem since the bombs were detonated high in the air. The flash burns of the Japanese were due to thermal radiation only. Following the Alamogordo atomic detonation, a numberof cattle grazing near the point of detonation developed lesions on their backs due to the deposit of fallout material (+). .\lso, following a detonation ut the Nevada TestSite, sixteen horses near the Test Site developed lesions resulting from fallout deposit on their hair, anointed with a heavy coconut-oil dress- backs (5). Knowlton et al. (6) described burns of the hands of four individuals who were handling fission product material following detonation of a nuclear device. These burns were due 3.6 of the hands occurred from an exposure of about 1 hour, resulting in doses between 3,000 and 16,000 rep of beta radiation (maximum energy about 1 Mev) with a smail gamma component considered to be insignificant. The lesions were described as developing in four phases: (1) An initial phase which began al- ing, resulted in heavy contamination. Decontamination of the head was slower than for the other parts of the body and may have enhanced the developmentof epilation and scalp lesions. Lack of Correlation With Hema- tological Findings AtTemprs Were Maneto correlate the severity and extensiveness of skin lesions with hematologic findings for individuals in the Rongelap group. No positive correlation was found with depression of any element. Thus, the contamination of the skin apparently did not significantly contribute to the total-body dose of radiation. largely to beta radiation. The gross lesions most immediately after exposure and consisted of an erythema with tingling and burning of the hands, reaching a peak in 48 hours and subsiding rapidly so that by 3 to 5 days there was a relative absence of signs and symptoms: (2) A second phase which occurred from about the