was already conservative based on comparisons with BEIR-111, we elected to use the 30-year whole body dose as provided us--not doubled. 5. For the 140 persons who returned to Bikini and were removed in August 1978, it was assumed that no children will be conceived by persons above age 40, that 300 children will be born after August 1978, and that all children born will be offspring of parents, both of whom returned to Bikini. The parental dose was obtained as follows: Average dose to males < 40 ye;rs old = 1.36 rem Average dose to females < 40 years old = 1.08 rem = 2.44 rem = 1.22 rem Total parental dose Parental dose used in calculations 6. The average dose values for persons who lived on Bikini were calculated from individual dose data (whole body and bone marrow) for 50 males and 49 females. 7. These values are tabulated in the appendix. The spontaneous incidence of birth defects was taken to be 10.7% of all live births from BEIR-111. 8. The normal incidence of cancer deaths was assumed to be 15%. A value less than the approximately 20% given for the U.S. population was used because the Bikini people have been and will probably be exposed to much lower limits of environmental carcinogens than people living in the U.S. and because of limited medical services and prevalence of other risks such as drowning, poisoning, etc. Other causes of death are probably higher in the Bikini population than in the U.S. population. We also suspected the average life span was less than in the U.S. population, which might tend to reduce the number of cancers that would occur in the elderly. 9. The largest dose a person might receive in a year was estimated to be three times the average dose. Data in the appendix for individuals show that the highest individual dose is more than twice the average but less than three times.