Figure 9. Early beta burnsof skin ( x 100), showing ex- tensive transepidermal damage, with milder damage to dermis showingcellular infiltration.? Table 7 ‘Epilation in Rongelap Group?? Incidence, % Severity of epilation Figure 7. Epilation at 28 days in 7-year-old girl.? Figure 8. Foot lesions at 29 days, showing deep involve- ment betweenfirst and secondtoes.” AgeOto5S (13) Age6tolti Age >16 (13} (38) Slight (1+) Moderate (2 + ) Severe (3+) 7.6 38.6 53.8 38.4 30.7 23.0 13.8 3.5 8.3 Total 100.0 92.1 27.6 usually more severe, often with bullae formation: they made walking painful and in somecasesinvolved secondaryinfections. Most of the lesions healed rapidly, with repigmentation. Microscopic studies and numerousskin biopsies during the acute stages of the lesions revealed marked epidermal injury with considerable atrophy and flatteningof rete pegs, ceils with pleomorphic nuclei, pyknosis and cytoplasmic halos, and giantcells (see Figure 9). Cells laden with pigment were frequently present throughout the epidermis, probably accounting for the gross pigmentation of the lesions. Severe damage to the dermis and blood vessels was not observed. An unusual observation was the developmentof transient bluish-brown pigmentation of the semilunar areas of the fingernails and toenails,first noted about 3 weeks post exposure in most of the Rongelap and Ailingnae people and seen, among the American group, only in Negroes. The cause of this pigmentation remains obscure. Since no specific treatment is known for beta burns, the lesions were treated by cleansing and use of ointments andlotions for symptomatic re-