13 Figure 9. Early beta burnsof skin ( xX 100), showing ex- tensive transepidermal damage, with milder damage to dermis showingcellular infiltration.? Figure 5. Extensive skin lesions in 13-year-old boy.? Table 7 Epilation in Rongelap Group?? Incidence, % Severity of epilation Slight (1+) ; lesions at Wdays;* tedesquamation.? == 7.6 Age6tol5 (13) Age >16 (38) 38.4 13.8 Moderate (2+) 38.6 30.7 Total 100.0 92.1 Severe (3+) Figure 6. AgeOtoS (13) 53.8 23.0 5.5 8.3 27.6 usually more severe, often with bullae formation; they made walking painful and in somecases involved 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 at- rophy and flattening of rete pegs, cells with pleomorphic nuclei, pyknosis and cytoplasmic halos, and giantcells (see Figure 9). Cells laden with pig- ment were frequently present throughout theepidermis, probably accounting for the gross pigmentation ofthelesions. Severe damage to the dermis and blood vessels was not observed. An unusual observation was the developmentof transient bluish-brown pigmentation of the semilunarareas 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 and lotions for symptomatic re- PRIVACY ACT MATERIAL REMOVED Figure 8. Foot lesions at 29 days, showing deep involvement hetween firat and second toes 2