~he reported in these studies, the ineidence of thyroid abnormalities appears to be hipher fn this proap than would be expected. However, dose cateulatious ta the Marshallese are subject to considerable uncertainty, and variability of dose among the exposed people must have been marked, A reevaluation of the thyroid doses will be undertaken in the near future based on more precise information regarding urinary iodine excretion in the Marshallese. As a result of the present findings, upwards the seriousness of the it will be necessary to revise internal hazard associated with fallout, Secondly, it has become increasingly evident that late effects of radiation of the thyroid gland, (neoplasias, hypothyroidism) are much more common sequelae than had been previously supposed. The high incidence of thyroid lesions in the Marshallese emphasizes the caution with which radiation must be used clinically, particularly in regard to the use of radioiodine in children, Robert A, Conard, M.D. Chief, Marshall Island Medical Surveys Medical Research Center Brookhaven National Laboratory mb