~7During the two-day period following the accident before the of the people occurred, the inhabitants absorbed radionuclides i out by inhalation and ingestion of contaminated food and drinkin Based on radiochemical analyses of pooled urine samples taken se after the accident it was estimated that the adult thyroid gland vacuation the fallwater. ral weeks main Rongelap group received about 160 rads from the radioiodine another 175 rads from the external gamma radiation. Taken into c tion in those calculations were the time and length of the fallou the isotope energies and half-lives of the various iodine nuclide the yield of the isotopes. Similar estimates for the smaller thy of the young children ranged from 700 to 1400 rads in the more he posed group. Though "beta burns" were prevalent in the neck regi believed the beta energies were too weak to have contributed sign to the thyroid dose. The thyroids of the Utirik children receive estimated 55 to 125 rads from iodine, plus the 14 rads from exte radiation, was detected in a 12-year-old girl in the more heavily exposed gr 2 further nodules were detected in 1964. In March, 1965, 5 other were noted and in addition hypothyroidism was diagnosed in two b had shown growth retardation. Five further cases were detected inj who Septem- ber of 1965 and 5 more in March, 1966, making a total now of 16 cakes with _ nodules plus two cases of hypothyroidism. 10 Only one nodule was und to be malignant. These cases are described in Table I (page 11). Ta (page 13} summarizes the incidences of thyroid abnormalities in th populations examined. Note that 79 percent of children less than of age at time of exposure in the more heavily exposed group devel thyroid abnormalities, in comparison with no thyroid pathology not children of the same age range of the non-exposed population or in lesser exposed populations. The incidence in those exposed at a g age is considerably lower, and only slightly above that seen for t exposed or less exposed populations. It should be noted that the nodules noted in the unexposed population were in the older age gr that is, greater than 50 years of age. In most cases the thyroid glands contained multiple nodules r in diameter from a few millimeters to a few centimeters. All were tender, some firm, others cystic, and Sometimes even hemorrhagic. lymphadenopathy was noted. The microscopic sections of the benign showed quite bizarre appearance with a wide variety of different s follicles, some small and atrophic, others large with hyperplasia cystic formation. The hyperplastic changes were characterized in cases by infolding of the epithelium giving an arboreal appearance. These changes resemble those seen in iodine deficiency goiter (adenomatoib goiter). The one case of cancer of the thyroid occurred in a 42-year-old wongpn and was of the mixed papillary and follicular type. A hypothyroid etiology for growth retardation noted in childreh in the exposed group is strongly suggested by the findings of definite} hypo- POE ARCHIVES 106 onard, R. A.: Personal Commmication.