subscapular area (unless he had been customarily shirtless). However, two persons developing skin cancer out of a radiation-exposed population of 82 (2.5%) is greater than expected if Black population studies are used for comparison (Fleming, I.D. et al.). Furthermore, there is a suggestion of a temporal association, for the cancers occurred 32 and 37 years after exposure. Therefore, the possibility remains that radiation exposure did contribute in a direct or indirect way to the development of basal cell carcinomas in these two patients. Table 2 summarizes the thyroid nodule findings in the exposed Marshallese through 1991. It includes the nodule described in the preceding paragraph, which is listed under the heading of “Occult Papillary Carcinoma." The number and types of nodules in the Comparison groupare also listed in Table 2, although the U.S. Departmentof Energy-sponsored program for surgical exploration of palpated nodules in this group was concluded in 1985. THYROID SURGERY FINDINGS, 1964 THROUGH1991 Thyroid nodules Only one thyroid nodule was diagnosedin the exposed population from January 1988 through December1991. That nodule occurred in a Utirik man who had been in utero at the time of exposure in 1954. The mother was in her third trimester at the time of exposure, her whole-body and thyroid-absorbed doses being estimated at 11 and 160 cGy, respectively. The patient’s estimated dose was, therefore, 11 cGy whole-body and 99 cGy internally to the thyroid, for a total thyroid dose of 110 cGy. This patient is the first of eight Utirrik persons exposed in utero to develop a thyroid nodule. (Two of four Rongelap persons who were in utero at the time of exposure have also had benign nodules removed). A thyroid lobectomy was performed at the Clinical Center, The National Institutes of Health. Histological review of the surgical material was performed by the four pathology consultants to the Marshall Islands Medical Program (see p. 16). Selected comments from their diagnoses are: Consultant #1 - “Thyroid nodule of histologically normal tissue which contains a tiny focus of occult papillary carcinoma.” Consultant #2 - “Adenomatous goiter in the colloid stage." Consultant #3 - "Nodule with fibrosis.... No evidence of cancer." Consultant #4 - "Tiny occult sclerosing papillary carcinoma.” A summary of this patient’s hospital case is included in Appendix C. The patient was returned home on thyroxine suppression. Introduction: Thyroid nodules and hypofunction among the exposed populations of Rongelap and, to a lesser extent, Utirik are well documented consequences of the BRAVO exposure. A recent reevaluation of external and internal radiation exposures in those populationsin all likelihood represents the definitive quantitative analysis of organ and whole-body radiation dose stemming from this catastrophe (Lessard et al., 1985). The thyroid dose received particularly close scrutiny because of early evidence of extensive thyroid injury and because an important mechanism of exposure was ingestion of a variety of radioiodines, an occurrence without precedent and therefore with unknown consequences. A final interpretation of the effect of fallout exposure on the thyroids of the exposed Marshallese has not been possible because of the protracted evolution of thyroid abnormalities following radiation exposure. The incidence of thyroid cancer has been reported to be elevated more than 40 years after radiation exposure (Shore et al., 1985; Schneider et al., 1978) and might includea lifetime at risk. However, for the past six years (1986 through 1991) only one new thyroid nodule (nonmalignant) has been detected im the exposed persons. Furthermore, there has been only one new nodule diagnosed in the Rongelap groupin the past ten years. (There have been two thyroid surgeries for recurrent benign nodules in the Rongelap group, but these are not included in the statistics that follow). Although occasional nodules will no doubt continue to be diagnosed, if for no other reason than that thyroid nodule prevalence increases naturally with aging,it is possible that the recent dearth of cases represents a pause that is 14