two fatalities that might be causally linked to hepatitis B virus, infection with this organism must be considered a public health problem of great concern. The Marshall Islands Medical Program annually tests all persons previously shownto be hepatitis B surface antigen-positive for the presence of alpha-fetoprotein, a tumor marker for hepatoma. Should an elevated level be detected the affected subject would be promptly referred for evaluation in the hope that early detection might permit curative resection of a localized lesion (Heyward et al., 1984). The question arises as to whether the exposed Marshallese are at increased risk for the late complications of hepatitis B. This problem was discussed previously (Adamset al., 1986), and it was noted that the prevalence of hepatitis B surface antigenemia was 3.3% in the Rongelap group, 18.8% in the Utirik crouyec 10.5%in the Comparison group. Thereis evideTe suggesting an association between radiation dose and prevalence of cirrhosis, but not hepatoma,in survivors of the atomic bombings in Japan (Asano et al., 1982). Assuming that two of the three deaths from hepatoma and cirrhosis in Marshallese resulted from chronic hepatitis B infection, the frequency of hepatitis B-related deaths, as percent of hepatitis B surface antigen- positive persons is: exposed Rongelap - 0% (0/2); exposed Utirik - 9.5% (2/21); Comparison group - 0% (0/10). ADENOMATOUS NODULES AS FUNCTION OF RADIATION DOSE AND TIME T REM ( thousands) 5 OR T —_ £6 l T T ] r J | T a s aan | 30 = —~ = a 2k io = | ovat 0 — = 10 | 14 1 8 Py jm 18 | » . —~ | * a a pm 26 30 34 YEARS POST-EXPOSURE Fig. 4: The time required to develop adenomatous nodulesfollowing radiation exposure appears,in this graph, to be dose-related. However, the thyroid-absorbed radiation dose was highly dependenton the age at exposure.