12 lying epidermis showed greatest damage. There was mild edemaof the pars papillaris with lymphocytic infiltration, particularly around the telangiectatic vessels. Atrophy of hair follicles was observed. Follow-up studies at six months and one year showed that the hyperpigmentation had in most cases disap- Fig. 7.—Photomicrograph of pigmented skin lesion three weeks after exposure (xX 100). Extensive transepidermal damage with less involved areas on either side. Loose lamination of stratum corneum, absence of Stratum granulosum, and disorganization of malpighian layer. Dermis shows mild edema of pars reticularis, indistinct capillary loops, moderately pronounced perivascular cellular infiltrate, and mild telangiectasia. cm peared. At the site of deeper foot lesions and the earlesions, there were pink-to-white areas that had not repigmented (fig. 5B). In these areas the skin appeared