tee inated 5.h.1. Potential Maximm in the USA The MIKE debris took about ten days to reach gummed papers exposed in the United Stgtes and the KING material took about six davs. In order to estimate the maximm activity that could be deposited in the United States from future Pacific tests of megaton yields, it is necessary to postulate the fastest possible transport. A review of nrevioue Pacific tests indicatss that the case of most rapid transport to the United States occurred with GREENIDUSE BOG, detonated 7 April 1951. Rochester, N. Y. and dani Washington, D. C. both reported approximately 1000 d/m in rain— _ four to five days after burst(2). Computation of high-level _ trajectories suggeststhat the core of the GREENHOUSE DOG bomb passed well south of Washington, so it is possible that the maximum rainout was also south of Washington and perhaps an order of magnitude greater than the activity reported. itis reasonable — oo. to assume that under similar meteorological conditions radioactive ' from rainout on the west coast would be higher than on the east coast because decay and dilution would have been operating over a shorter period. The increase would probably be less than an order of magnitude, however, probably a factor of two or three. Summarizing, it is estimated that the maximum possible rainout over the United States from pegaton-yield tests in the | Pacific would lie in the range 10° to 10° d/m. This crude estimate is based on the assumption that radioactivity from rainout, under similar meteorological conditions, is directly proportional to the bomb yield. The meteorological conditions necessary for maximm reinout are fast westerly winds in the upper troposphere and rainout from high levels over the United States. These conditions wuld . be expected in winter and spring rather than during sumer and fall. SOUTHEAST AND EAST ASIA ' . Southeastern and eastern Asia is the only area outside of the Western Pacific which received activity of the order of 104 d/n. Forthermore, it is an area where even greater radioactivity might be expected. The highest radioactivity collected at Clark Field, P, I. from MIKE debris was about 200,000 d/m (with no rein) and 3,000 d/m after KING. , = 38 - : me Oa, JG) mean nn he Pre acreainem ehnant . ‘ “‘ Se Ai Ne Se Ete le 5.5