erg OFFICIAL USE ONLY 1. INTRODUCTION Bikini Atoll (Figure 1) was a site for atmospheric tests of nuclear devices from 1945 to 1958. The population of 166 Bikinians was moved from the atoll in March 1946, first to Rongerik Atoll, then to Kwajalein Atoll and finally, in November 1948 to Kili Island. The land area at Kili is about one-tenth that at Bikini Atoll and there is no lagoon. Therefore, access to Kili is difficult, often impossible, and sea foods are scarce, The results of a radiological resurvey of Bikini in 1964 by the University of Washington's Laboratory of Radiation Biology indicated that Bikini might be radiologically safe for permanent habitation. request from the High Commissioner of the Trust Territories of the A Pacific to the Atomic Energy Commission (AEC) in 1966, to rehabilitate Bikini, resulted in an extensive survey of the atoll in the spring of 1967. This survey emphasized external radiation measurements, including in situ gamma-ray spectrometry, although some food items were collected to supplement data from the 1964 survey. The 1967 survey party included personnel from the AEC's Health and Safety Laboratory, the Division of Biology and Medicine (DBM), the U.S. Naval Radiological Defense Laboratory, the Trust Territory, and the University of Washington. The data were summarized by DBM and were presented to a panel of experts (referred to as the Ad Hoc Committee in this report) assembled by DBM for evaluation of potential radiological hazards. Most of the participants in the 1967 survey attended the presentation to provide details not included in the summary. The Committee concluded that Bikini could be safely reoccupied, but recommended some simple measures that should be instituted to reduce exposure to radiation. These included reduction of the coconut crab population (because they contain high concentrations of 90sr) and covering the village area at Bikini Island with coral gravel from the beaches. The latter is consistent with local custom. The Committee also recommended that old structures and other such debris from the tests be removed from the islands and beaches and that Bikini Island be further monitored during the clean-up. Additional monitoring was necessary because dense vegetation on Bikini and Eneu Islands, especially, made it impractical to survey more than a few transects across the islands in 1967. The Committee's recommendations were made to the Chairman of the AEC who informed the Secretary of the Interior, the Administrator for the Trust Territory of the Pacific. 2. CLEAN-UP OF BIKINI ATOLL The clean-up phase of the rehabilitation of Bikini Atoll, a coop- erative effort by AEC and Department of Defense, was begun in February 1969, 1 OFFICIAL USE ONLY