There was a delay of two and one-half days befure satisfactory decontamination was possible. The presence of radioactive materials on the skin during this pertod imereased the dose to the skin. However, the dose rate fell off rapidly and decontamination would have to have been very prompt in order 4 be effective. 3.6 CORRELATION WITH HEMATOLOGICAL FINDINGS Attempts at correlation of the severity and extensiveness of skin lesions with maximum depression of platelet, lymphocyte, and neutrophile counts were made for individuals tn the Rongelap group. No pugitive correlation was found. Thus the contamination of the skin apparently did not significantly contribute to the total-body dose of irradiation. 3.7 DISCUSSION There hag been little previous experience with radiation dermatitis resulting from expo- sure to fallout matertal from nuclear detonations, and the general consensus until now has been (hut the hazard from fallout material was negligible. With the Hirughima and Nagasakt detonafons, fallou! materjal was not a problem since the bombs were exploded high in the air. The flash burns of the Japanese were purely thermal, From the present experience il is quite evident that following detonation of a large scale device close to the ground, serious exposure of personnel may occur from fallout material, even at considerable distances from the site of detonation. The incident described in this paper 1g the first example of large numbers of radiation burns produced by exposure to such fallout material. . Knowlton, et al.‘ described burns of the hands of four individuals who were handlingfission product material following an experimental detonation. Also, following the Alamogordo detonation, there were a number of cattle that developed lesions due to deposit of fallout material on their backs.* In addition, there were a number of sheep that developed lesions closely resembling radiation burns following a Nevada detonation. However, Lushbaugh® reported that the histopathological characteristics of these lesions did not conform in all respects to radiation dermatitis. It is of considerable interest to compare the present experience with that accepted in the past as the typical] course of radiation burns of the skin. The grosag lesions of the hands described by Knowlton, et al. occurred from an exposure of about une hour, resulting in doses between 3000 and 16,000 rep of beta radiation (maximum energy about 1 Mev) with a small gamma component considered to be insignificant. The lesions were described as developing in four phages: (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; (2) A second phase which occurred from about the 3rd to the 6th or 8h day and was churacterized by a more severe erythema; (3) The third phase at 8 to 12 days, which was characterized by vesicle and bullae formation. The erythema spread to new areas during the following two weeks, and the active process subsided by 24 to 32 days. The bullac dried up, and desquamation and epithelization (ook place in less severely damaged areas; (4) The fourth phase or chronic stage was characterized by further breakdown of skin with necrosis in areas which were damaged sufficiently to compromise the blood supply. Atrophy of the epidermis and loss of epithelial structures took place, which necessitated skin grafting in some cases. Robbins, et al.’ reported six cases accidentally exposed to scattered cathode rays (beta) from a 1200 kv primary beam with exposure time of about 2 minutes and a rough estimation of dose to the skin of between 1000 and 2000 rep. The lesions described were similar to those reported by Knowlton, et al.‘ with a primary erythema developing within 36 hours, secondary erythema with vesiculation and bullae formation appearing about 12 to 14 days later; and, in the more severely affected, a tertiary phase characterized by further breakdown of the skin. In comparisor. with severe roentgen ray reactions these investigators stress the unique periodicity of cathode ray burns, relative absence of deep damageto the skin, less pain, rapidity 42