including plasma protein bound iodine and cholesterol studies. Until recently these examinations had not revealed any apparent abnormality of the gland. In 1963 a thyroid nodule was first detected in a 12 year old exposed girl and in the following year two more teen age girls were discovered to have nodules. Since then the incidence of thyroid abnormalities has increased and at the present time 19 people with thyroid abnormalities have been noted, all of these occurring in the more heavily exposed group except one in an adult in the Ailingnae group. Only three such cases have been detected in adults, the remaining 16 cases having occurred in children exposed at less than 106 years of age. The following table shows the high incidence(84%) of these abnormalities in this younger group. THYROID NODULES (INCLUDING HYPOTHYROIDISM) IN MARSHALLESE POPULATIONS (R=Rongelap; A=Ailingnae; UT=Utirik; C=Unexposed) Age No. in Group Estimated Gamma Thyroid Dose(rads) Dose (1*, rads) 70 Thyroid Group At Exposure R <10 19 L75 A <10 6 69 275-550 0.0 Ur <10 40 14 937-110 6.0 C <10 61 0 0 0.0 R >10 36 175 160 5.5 A >10 8 69 55 12.5 Ur >10 59 14 iS 3.4 C >10 133 0 0 2.3 - 700-1400 Nodules 84,2 #*In estimating the thyroid doses to the Ailingnae and Utirik exposed group, it was assumed that such doses were proportional to the thyroid doses of the Rongelap exposed group, based on relative whole body gamma dose received. we fo 4,d se.