taken at 25 feet were multiplied by a factor of 2 in order to obtain a reasonable approximation of the true ground reading. The factor of 2 was experimentally determined and checked at various times during the operation. Ex- perience indicated further that any reading taken from an altitude of 50 feet or higher was extremely difficult to correct to true ground values due to the asymmetry in the radiation fields and the topography of the various islands. 2.1.4—Monitors for recovery parties were provided by TU-6 when necessary. Demand was quite small except for the Quince and Fig events when 28 TU-6 monitors were used, In general, however, projects provided thelr own monitors as members of the recovery party. Monitors were responsible to the party leaders, who were expected to accept a monitor's advice and plan their operations accordingly. . 2.1.5—Laboratory facilities at Enfwetok for radiochemistry work were obtained from the U. S. Army Signal Corps, The AN/MDQ-1 radiochemistry laboratory trailer was parked near the Rad-Safe Building and used for all sample preparation and counting. Approximately 450 water, food, and soil samples were processed and counted. Primary interest was centered in gross beta-gamma activity or total alpha activity. No detailed radiochemistry studies were required or attempted. In addition, numerous air filter samples were counted for alpha activity following the Quince event. 2.2 Shots and Survey Results In the course of the operation, contamination from any one shot did not OR alt nee materially interfere with preparations for subsequent events. This was due in large part to the fact that most of the devices were fired on barges several hundred yards off shore rather than on the surface of an island or on towers. In comparison with Operation Redwing, on-site contamination during Hardtack was remarkably light. Fall-out from the Fir event on Bikini contributed approximately 1,200 to 1,500 mr total dose to thoseliving at Eniwetok Atoll but this did not interfere with any Enfwetok operations. Close rad-safe control over accumulated dosages was effective in countering the dosage received from the Fir fall-out. Very little decontamination of land areas was required since the contamination levels at critical stations were generally quite low. The alpha contamination resulting from the Quince event required very close control and considerable decontamination effort at the zero site in order that preparation for the Fig event could proceed. Table. 2.1 gives a summary of the various events at Eniwetok Atoll. The H+4 hr survey results are indexed by figure number in Table 2.1. - 12 - wee