exposure to tropical sunlight, potentially carcinogenic in ityelf, may increase the probability of neoplastic change. The influence of the sub-lethal whole body exposure received by these people on skin cancer induction is not known. The transverse band 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 Table 3.3) ~~ SURFACE DOSES IN REP REQUIRED TO PRODUCE RECOGNIZABLE EPIDERMAL INJURY Investigator Antmal Average Energy (Mev) Isotope Surface Dore (rep) Henshaw, et al?! Rats pa 0.5 1,600 - 4,000 Raper & Barnes”? Raper & Barnes” Rats Mice Rabbits Sheep p? pe Pp? sr” 0.5 0.6 4,000 1,600 Henriques” Pigs s* 0.05 20,000 — 30,000 Henriques” Pigs co 0.1 4,000 - 5,000 Henriques” Pigs Csi3t 0.2 2,000 — 3,000 Henriques” Pigs Sr*® 0.3 1,500—2,000 Henriques” Pigs y" 0.5 1,500 ~ 2,000 Henriques” Pigs y” 0.7 _ 1,500-2,000 Raper & barnes™® Lushbaugh® Morttz and Moritz and Moritz and Moritz and Moritz and Moritz and 0.5 0.3 5,000 2,500 - 5,000 nature of the pigment is 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 peculiar to negroid races. The pigmentation was apparently produced by as 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 result of this accident the following conclusions can be drawn with respect to beta damageto the skin. a. Serious skin contamination of personnel from fallout may occur many miles from the detonation of a nuclear device. Resultant radiation damege to the skin may be the major ra- diation effect under conditions where early evacuation from the field of radiation reduces the whole body exposure. b. Fairly extensive skin lesions resulting from fallout beta radiation apparently produce little or no systemic or hematological) effects. c. Decontamination of the skin must be promptto 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 symptoms of skin damage are evident. % Ss Woo 45_. > e. Clothing and/or any type of shelter gives almost complete protection to the skin.