The program established an organization to provide radiological safety (radsafe) expertise and services to the separate components of the task force who were responsible for personnel safety within their commands. Personnel were trained in radiological safety, and standards governing maximum permissible exposures (MPE) were established. Film badges were provided to a large portion of the participating personnel. Persons likely to be exposed to radiation were badged as well as a representative group of the remainder. An extensive weather forecasting group was estab- lished in order to predict wind directions and areas of potential fallout. Personnel were evacuated from danger areas before each detonation and reentry to contaminated areas was restricted to the personnel required to retrieve important data. The amount of radiation exposure for these per- sonnel was monitored. TEST OPERATIONS AND EXPOSURES The first event of this series, designated BRAVO, had a yield of 15 MT and was the largest device ever detonated in atmospheric nuclear testing by the U.S. Government. Significantly exceeding its expected yield, BRAVO, detonated at Bikini Atoll, released large quantities of radioactive materials into the atmosphere, which were caught up in winds that spread the particles over a much larger area than anticipated. This resulted in the contamination and exposure of some individuals either stationed or residing on distant atolls or aboard various vessels. Acute radiation effects were observed among some of these people. A limited number of JTF 7 personnel received radiation exposures considerably in excess of the initially established CASTLE MPE. This opera- tional limit was established at 3.9 roentgens (R) gamma within any 13-week period of the operation. In particular, three members of the U.S. Navy Bikini Boat Pool had heavily exposed badges with readings from 85 to 95 R, and 28 Army and Air Force personnel had film badge exposures that read as high as 78 R. All these men were medically evaluated at Kwajalein. Sub- sequently, follow-up on 29 of them was done at Tripler Hospital in Hawaii.