Table 1. Percent of persons in Marshallese populations having thyroid nodules (1979). Age <18 in 1954* No. % with nodules 42 85 52.4 9.4 553 435 103 102 1193 Group % with carcinoma Age >18 in 1954. No. % with nodules % with carcinoma 4.8 2.4 44 79 15.9 11.4 4.5 1.3 0.7 1.4 3.9 1.0 0.2 0.2 1.0 0.0 115 38 59 90 11.3 7.9 6.8 4.4 0.9 2.6 (i case) 0.0 0.0 1.2 0.25 292 Exposed in 1954 Rongelap Utirik ae Comparison populations Rongelap Utirik Wot je Likiep ALL 8.2 0.7 *The comparison populations include children not yet born in 1954. prevalence not subtracted from exposed estimates. Unexposed **Includes 19 people exposed on Ailingnae. from natural radiation might have been subtracted from the above estimates. Exposure to natural radiation during the years the people were away from their home island was not added to the above doses since comparisons are to be made with unexposed population statistics, in which such exposure is inherent. Table 3 shows the expected percentage of persons with thyroid nodules and cancer due to exposure to residual radiation on Rongelap and Utirik. Estimates are calculated for the highest exposure doses assuming continuous habita- tion on the islands (half-time habitation for children). The table shows that the percentage of people with thyroid nodules and cancer would not be detect- able in a population this size and would be far below the spontaneous incidence. The data presented are probably overestimates in view of the factors discussed above. - 105 -