ACOBY Marshall [Islands Radiological Safetv Program and Rongelap/Utirik Dose Reassessment Project - A Historical Synopsis Preface From the mid.1940's to 1958, the United States conducted its’ high-yield nuclear weapons tests at Bikini and Enewetak Atolls in the tropical Pacific. These remote groups of small islands lie about 2,500 miles southwest of Hawaii, and are part of the “Marshall Islands District of Micronesia. At that time, most of “ticronesia was the political ward of the United States which acted as trustee under a United Nations mandate establishing the Trust Ter- ritory of the Pacific Islands (Micronesia) after World War If. this region, known as the Marshall Islands, Currently, intends to enter into a Compact of Free Association with the United States. The largest of the nuclear tests was the “BRAVO” event which took place at Bixini Atoll on March 1, 1954. Radioactive fallout from this detonation was carried eastward by prevailing winds, and resulted in radiation exposures to Marshallese people living at Rongelap and Utirik Atolls a few hundred niles away. The exposed population of these atolls plus a comparison population are frequently examined by Brookhaven National Laboratory Medical personnel to detect and care for long-term health effects due to their exposure to radiation from the weapons testing program. In addition to the high-level radiation exposures to the Rongelap and Ucirik people, the nuclear tests also left a legacy of environmental radioactivity which, because of its lower level, is not expected to cause adverse health effects. However, residual radioactivity in the environment will contribute radiation exposures above natural background levels to people living in these areas.