exposure to tropical sunlight, potentially carcinogenic in itself, may increase the probability of neoplastic change. The influence of the sub-lethal whole body exposure received by these people on skin cancer induction ig not known. The transverse and of pigmentation that was observed in the fingernails has been pre- viously observed by Sutton™ in a negress who received 150 r of soft X-ray to the hands. The “te Table 3.3) SURFACE DOSES IN REP REQUIRED TO PRODUCE RECOGNIZABLE EPIDERMAL INJURY Investigator Antmal Average Energy (Mev) Tsotope Henshaw, et al?! Raper & Barnes? Rats Hats py p2 Raper & Warnes”? Rabbits Surface Dose (rep) 0.6 0.5 1,500) 4,000 4,000 Sheep p? sr” 0.5 5,000 Henriques”? Pigs s* 0.05 20,600 ~ 30,000 Henriques” Pigs CoM 0.1 4,000 - 5,000 Henriques Pigs cs'? 0.2 2,000-3,000 Pigs sr*° 0.3 1,500—2,000 0.5 1,500 — 2,000 0.7 _ 1,800-2,000 Raper & Barnes*® Lushbaugh® Moritz and Moritz and Moritz and Moritz and Henriques™® Moritz and Mice ye Henriques” Pigs y" ‘Henriques”’ Pigs y* Moritz and 0.5 0.3 . 1,500 2,500 - 6,000 nature of the pigment ia not known. Since it occurred in all exposed American Negroes, many of the Marshallese, and none of the American whites, it is a radiation response pecultar to negroid races, The pigmentation was apparently produced by ag little as 75 r of gamma radia- tion since the American Negroes developed the phenomenon in the absence of significant contamination of the hands. 3.8 CONCLUSIONS As a resuit of this accident the following conclusions can be drawn with respect to beta damage to the skin. a. Serious skin contamination of personnel from fallout may occur many miles from the detonation of a nuclear device. Resultant radiation damage to the skin may be the major radiation effect under conditions where early evacuation from the fieid of radiation reduces the whole body exposure. : b. Fairly extensive skin lesions resulting from fallout beta radiation apparently produce little or no systemic or hematologica) effects. c. Decontamination of the skin must be prompt to be effective because of the initial high beta dose rate. d. A latent period of a few days to three to four weeks may elapse before signs and symp- toms of skin damage are evident. e. Clothing and/or any type of shelter gives almost complete protection to the skin.