C FICIAL USE ONLY - 5 - if the doubling dose is of the order of 60r or less. Even if no increase can be demonstrated, however, an estimate can be made of the minimum value for the human mutation doubling dose, Neel and Schull propose an initial "R and D' year followed by a four-year sampling program at ABCC and a final two-year data analysis period. The proposal has been approved by the BM Research Committee and by the National Academy of Sciences, but Japanese approval remains to be negotiated. CLEAN-UP OF BIKINI ATOLL, Dr. N. F. Barr, Assistant Director for Radiological Physics, DBM, and Mr. T. McGraw, Division of Operational Safety, presented a report on the status of the Bikini resettlement program. The results of surveys conducted in 1969 and 1970 are consistent with those of earlier surveys and support the conclusions and recommendations of the ad hoc committee which in 1968 assessed the radiological hazards of resettlement of Bikini. DOS and DBM staff will meet on September 14 with contractors and representatives of the Department of Interior and Environmental Protection Agency to discuss future monitoring and research activities. PU EXPOSURE AT ROCKY FLATS, Mr. Robert J. Catlin, Assistant Director for Health Protection, Division of Operational Safety, reviewed in some detail the circumstances of the Rocky Flats incident of August 22, 1971, which led to receipt of substantial lung burdens of Plutonium-239 by two radiation workers at Rocky Flats. He discussed the decline in lung burdens over a period of time, resulting from elimination of plutonium through the feces and urine, and for one individual by three lavage procedures. The lavage was successful in removing approximately 10% of the estimated lung burden. DTPA was administered to both individuals, Direct measurements of Plutonium-239 in the lungs indicated that the lung burdens estimated (based upon measuring Americium-241 and assuming a Plutonium to Americium ratio) might be too high by a factor of two. Dr. Joseph Goldstein, Chief, Medical Branch, DBM, presented medical progress highlights on the Rocky Flats accident. Areas of importance to the care of the two internally exposed individuals, and the chronological clinical course during the period Aug 3 22 to September 8, 1971, inclusive, were reviewed. The initial lung Pu burdens were reported as approximately 9 Maximum Permissible Lung Burdens (0.16 nanocuries of 239Pu = 1 MPLB) for Mr. Smith and 28 MPLB's for Mr. Olveda. Both values were derived indirectly from measurements of 24lam. On August 22 both individuals refused DTPA intravenous treatment. This was not pressed by the physician in charge because he was informed that they were exposed to oxides which are not responsive to DTPA. Subsequently, it was learned that plutonium chloride was a constituent of the aerosol. These daily DIPA treatments were given Mr. Smith beginning August 30. His urinary excretion of plutonium increased from .05 to about 2.5 nci/day after the initial DTPA injection. On September 8 he had 7.3 MPLB of 239pu, OFFICIAL USE ONLY