A number of laboratories in the US were involved in these studies with Brookhaven National Laboratory (New York), and the Laboratory of Radioecology, University of Washington (Seattle), being the prime contractors for the medical and environmental monitoring programs respectively. These followup studies resulted in the Utirik and Rongelap inhabitants being returned to their islands 120 days and 3 years respectively after evacuation. Since their return, the medical and environmental monitoring programs have identified: a. the occurrence of thyroid nodules in the exposed population b. the existence of regions showing radiation levels significantly above natural background, and c. food from such areas, such as coconuts, coconut crabs, etc., also exhibiting Significant amounts of fallout radioactivity. The suddenness of the BRAVO event had the US ill prepared to truely understand the Magnitude of the problem. There were many facts of radiation exposure of this kind that were not known, thus, the programs instituted at that time were essentially investigative and structured to address acute effects. The atmosphere therefore was one of caution and the need to assure the exposed inhabitants was limited by the lack of adequate information about the effects of radiation. Therefore, it was not surpris- ing that certain circumstances beyond the control of either party began to create an environment of doubt which in turn lead to distrust. a. A few of these circumstances were: The Rongelap people cooperated during the annual examinations, but naturally, since they felt well after the acute effects subsided, they questioned the need for continuation of the examinations. However, the annual examinations were con- tinued and the explanation given that there might be possible late effects from their initial exposure which could develop even though they were feeling well now. The later incidences of thyroid nodules and one leukemia victim demonstrated the need for continuing the medical examinations but pointed out the fact that the doctors were not certain of the degree of exposure of the thyroid due to fallout. This was especially true with respect to the children because their thyrajds being