expesures of personnel so as to spread the MPE of 3.9r for each individual over the entire period of participation. In recognition of the prebable inadequacy of the 3.9r in some cases, provision for a waiver of the MPE was built into the CASTLE plan. In planning for the radiological aspects of the shots them- selves, some data could be utilized from previous detonations, both at the Nevada Proving Grounds (NPG) and the PPG, but in general the CASTLE program included shot conditions not previously encountered, i.e., surface shots on barges in relatively shallow water and one shot on a small sand spit. Past experience and general presump- tions seemed to indicate that the local and long-rangs contamination problems would be most urgent for the Namu Island shot »Lswori) at Bikini and considerably less urgent for the barge shots off Yurochi Island at Bikini. As the shots progressed it became more and more apparent that the planning assumpticns were justified. With the exception of - [sear 7, the assumptions were sufficiently valid to predict the end result with a fair degree of accuracy. As a general statement, SHOT /‘behaved much like a highly contaminating ground surface burst. The great amount of solid material carried up into the col- umn and mushroom returned to the ground forming roughly an elliptical isodose line pattern on the shot atoll. Contamination of the Enyu and Eninman camp sites had been predicted from the [S407-A wind pattern, although resultant intensities, particularly on Enyu, were higher than anticipated. 196