. Radiation Safety and Cleanup Preparations 201 naturally occurring radioisotope which enters the body through diet. A of 1600 normal adult man hasa tissue concentration of K-40 on the order pCi/g per kilogram, thus, levels up to several thousand pCi are normally measurable in urine. On a random basis, some samples were analyzed specifically for Cs-137, Co-60, or Co-57. The GB count was indicative of any beta-emitting isotopes (Cs-137, Sr-90, and Co-60) which might have been taken up at Enewetak. If any results had indicated possible significant uptake of beta-emitters, specific tests for Sr-90 or Cs-137 would have been made. ‘‘Significant uptake’’ was defined as a GB value on the order of 5 nanocuries (nCi) (5,000 picocuries) per liter and a GB-to-K-40 ratio exceeding three.43.44 The highest GB value reported was 3.6 nCi. In this case, the corresponding K-40 value was 3.2 nCi, so the GB/K-40 ratio was 1.13. The highest GB/K-40 ratio was 3.05. In that case, the GB value was 0.351 nCi. Thus, there was no significant uptake of beta-emitting isotopes. Plutonium concentration was reported in termsof pCi per 24-hour urine sample. As a trigger level, the American Health Physics Society Plutonium Bioassay Committee has proposed that, if the plutonium concentration exceeds 0.20 pCi per 24-hour sample, a second sample should be taken for verification. None of the 2,000 24-hour urine samples even approached this level. All but six of the 2,000 samples had readings below the minimum detectable activity (MDA), and the six that exceeded the MDA were one reading at 0.05 pCi, two at 0.06, two at 0.08, and one at 0.11 pCi. In each case where the MDA was exceeded, dose estimates were made. The estimates indicated that no significant doses were sustained. Moreover, a second sample was obtained from each individual and, in each case, the sample was less than MDA. Extensive recording of all radiation safety data was accomplished. In addition to recording personal doses in each individual’s military records, a permanent computerized data baseof all radsafe information has been established at DNA’s Field Commandin Albuquerque. In summary, the exhaustive data accumulated over the 3 years of the project do not indicate any area or instance of concern over radiological safety. All doses, internal and external, were minimal. ENJEBI ISLAND SURVEY BEGINS: 15 JULY 1977 Before radiological cleanup could begin, the techniques for locating and removing contaminated material were to be thoroughly tested and refined in the field by cleanup forces. The techniques to be tested included debris survey by the FRST,in situ soil survey by DOE-ERSP, and brush removal and contaminated soil excision by the USAE.It was planned thatthe tests