a D 12/3/79 Mrs. Ruth G. Van Cleve, Director Office of Territorial Affairs U. S. Department of the Interior Office of the Secretary Washington, D.C. 20240 Dear Mrs. Van Cleve: Reference is made to your letter of October 22, 1979, in which you state that the Department of the Interior is considering the agricultural redevelopment of Enjebi Island and the reestablishment of a commmity on that island for the Enjebi people. As part of this consideration you requested estimates of the time which must elapse before exposure levels on Enjebi Island would meet exposure limits. Current estimates of the number of years which must pass if exposure limits are to be adhered to are based upon the potential dose estimates provided in the Preliminary Dose Assessment Report prepared by the o ; . = staff of the Lawrence Livermore Laboratory (LLL). fhese dose estimates a have been compared to tHe exposure gufdance;-and, based upon known ~ ot radioactive decay Yates of“the radionuclides involved, time intervals have been:calculated. U. S$. Federal Radiation Council recommended exposure levels (adopted also Pyce Enviroqmental Protection Agency) invididual ‘in any. one. year Cand ¢ are 500 «avem tothe,maximum exposed. assumes“that the naximanexposed individual does not vary ‘from.the average population exposure by. more than a3 factor‘of 3, resulting in a recommended average population. exposurelevel of2170 mre “peryear) and 5000 mrem over a 30 year period. Atomic Energy Commission recommendations, recognizing the uncertainties inherent in ‘such guidance for the maximum dose estimates, were one-half of the FRC Cm eee tp epee sopra? oot we Or Ts emtengmeee maT ny as oat yee: 2. fare a En ate ye