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 eonsequently developed only very mild beta lesions, c. Clothing. Asingle layer of cotton material offered almost complete protection, as was demonstrated by the fact that lesions developed almost entirely on the exposed parts of the body. 5.54 Factors Favoring Lesions the Development of a. Areas of more profuse perspiration. Lesions were more numerous in areas where perspirationis abundant suchas the folds of the neck, axillae, and antecubital fossae. b. Delay in decontamination. There was a delay of 1 or 2 days before satisfactory decontamination was possible. The prolonged contact of radioactive materials on the skin during this period increased the dose to the skin. However, the dose rate fell off rapidly and decontamination would have had to be prompt in order to have been most effective. c. Difficulties in decontamination. The thick hair, anointed with a heavy coconut-oil dressing, resulted in heavy contamination. Decontamination of the head was slower than for the other parts of the body and may have enhanced the development of epilation and scalp lesions. 3.6 Lack of Correlation With Hema- tological Findings ATrempts 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 sig- nificantly contribute to the total-body dose of radiation. S011 2e 35 3.7 Discussion Tuerr 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 scale 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 thefirst 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 numberofcattle grazing near the point of detonation developed lesions on their backs dueto the deposit of fallout material (4). Also, following a detonation at the Nevada Test Site, sixteen horses near the Test Site developed lesions resulting from fallout deposit on their 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 largely to beta radiation. The gross lesions 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 small gamma com- ponent considered to be insignificant. The lesions were described as developing in four phases: (1) An initial phase which began almost 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