TITLE BUDGET AND REPORTING CODE Dose Reassessment for Rongelap DATE PREPARED HA-0O2-01-01 03/31/80 and Utirik CONTRACTOR NAME CODE Associoted Universities, Inc. 20a. WP NUMBER TASK NO. REY, NO. BNL 0 Facility Requirements. It is anticipated that work for this proposal will use existing Laboratory facilities and site utility services. 20b. Publications. Data generated in this study has been used in other reports. 20c. Purpose. To look for correlations between the incidence of thyroid nodules in the inhabitants of Rongelap and Utirik Islands (Marshall Islands) and the reassessed dose estimates. This study will fuse together all available information on fallout from the BRAVO test and using advanced analytical techniques (now available) derive realistic dose estimates to the inhabitants of Rongelap and Utirik. The results should provide information towards assessment of the risk coefficients for radiationinduced thyroid disease. 20d. Background. Incidence of thyroid nodules, benign and malignant, in the exposed popula~ tions of Utirik and Rongelap has indicated critical differences in correspondence between nodule incidence and thyroid dose for the populations. The estimated external dose received from the time fallout began to the shows that the Rongelap population received an external dose time of evacuation (175 rads) which was about 13 times that for the Utirik population (14 rads), and the thyroid dose was about 10 times larger, whereas the incidences of thyroid nodules in the two popula"tions were not significantly different. A preliminary study has indicated that the critical area of investigation is the period starting from the beginning of fallout to the completion of evacuatien for both the islands. In addition, the fact that the Utirik population returned within 120 days following evacuation, whereas the Rongelap population returned only after three years, requires that we look closely at the Utirik population in terms studies would, of a longer exposure period, therefore, have both internal and external. Further to concentrate on the re-examination of all avail- able data in reports issued by various agencies during that period, consultations with scientific personnel involved at that time, identifying the areas of uncer- tainty, and using appropriate computer programs to analyze the data. The end result will enable us to look for correlations between the incidence of thyroid nodules and the reassessed dose estimates. bh ATOL-S