-2led to the decision to clean up and rehabilitate that Atoll. The Department of Defense, Department of the Interior (DOI), and AEC (now ERDA) participated in a joint effort of cleanup and rehabilitation of Bikini Atoll starting in February of 1969, Cleanup was completed in the fall of that year. Agri- cultural rehabilitation and housing construction is being conducted by DOI. The decision to return the Enewetakese to their atoll led to a comprehensive survey conducted at Enewetak in 1972-1973. (See reference 1Q) A regional survey planned for 1976 will provide base-line radiological data for future dose assessments throughout nearly all of the northern Marshall Islands which may have been affected by the testing program. Environmental evaluations at Rongelap and Utirik Atolls have been undertaken periodically in association with ERDA's medical evaluations program there over the past 20 years. (Nat, suggest we cite Bob C. references here. ) From all of these earlier surveys, it became apparent that periodic environmental monitoring and dose assessments must be made for Bikini, Enewetak, Rongelap and perhaps other atolls in the northern Marshall's to maintain a current radiological data base and to provide current information on individual and population doses. This followup monitoring is being performed by Brook- haven National Laboratory at the request of the Division of Operational Safety, ERDA. RADIOLOGICAL CONCERNS The primary radiological problems are the result of residual fission and activation products in the terrestrial environment. They have been identi- fied by previous environmental surveys as follows: 1. External radiation levels significantly higher on some islands in an atoll compared to levels on lightly contaminated islands. 2 a we: Fission and activation product radioactivity in certain terrestrial tr wae ep st “vi. my ‘wy re a7 ~~