FPN ee From: W. J. Bair The Advisory Group is of the opinion that the recommended cleanup criteria as discussed in item 2 below will result in average transuranic radiation doses to subsequently exposed populations that will be commensurate with proposed EPA guidelines. The EPA considers its guidance levels to be equivalent to a lifetime risk of about 14 premature cancer deaths per 100,000 persons exposed and to perhaps an equal number of genetic effects, although these estimates are based on many uncertain assumptions and are generally considered to be quite conservative. An estimate of 14 cancers per 100,900 people would correspond to a 3% chance of one cancer appearing in a population of 200 people exposed to EPA guidance levels for their lifetime; or expressed differently, to a probability of one cancer in every 2100 years (assuming a constant population size). 2. Considering the physical and ecological limitations to removal of transuranics from the Enewetak Atoll], the Advisory Group recommends the following. From the information currently available and used for dose assessment, we believe that cleanup of all one-quarter or one-half* hectare areas exceeding (with 70% confidence) 40 pCi/g of surface (0 to 3 cm.) soils of village islands will provide a reasonable expectation that doses in the bone and lung will be commensurate with the EPA guidance. In terms of radiation dosesparing benefit to future inhabitatants, cleanup of a standard area on a village island is worth about 4 times as much as cleanup to a given level on an agricultural island and 12 times as much as cleanup of the same area to the same level on a picnic island. However, in the light of existing contamination levels and available cleanup resources, it would appear that cleanup of all one-quarter hectare areas on village islands that exceed 40 pCi/g should receive first priority. Because the other islands may have increased use over that currently assumed, a second priority should be the cleanup of agriculture island half-hectare areas exceeding (with 70% confidence) 80 pCi/g. A third priority should be the cleanup of picnic island half-hectare areas exceeding (with 70% confidence) 160 pCi/g. If resources are exhausted, some islands may not be cleaned up; final dose assessment may indicate that these islands will have to be permanently quarantined. We note that the soil profile on Pearl is anomalous since the concentration of transuranics appears to be uniform with depth. We believe that the possibility of effective cleanup for use as a village or agriculture island is remote. However, the possibility of covering Pearl with the less contaminated soil from the village islands and, perhaps, from the agricultural islands should be considered for Towering the average surface contamination levels and reducing the logistics problems of transporting the soil from the other islands to Runit. *1/4 hectare if IMP readings are taken on a 25 meter arid; 1/2 hectare if a 50 meter grid is used.