devices were developed by the AEC, the civilian agency authorized to per- form this activity by the Atomic Energy Act of 1946. The devices were tested at the PPG by a joint military and civilian organization, designated as Joint Task Force 7 (JTF 7). This was a mili- tary organization in form, but was populated by military, civil service, and contractor personnel of the Department of Defense (DOD) and AEC. The commander of this force was the appointed representative of the AEC and reported also to the Joint Chiefs of Staff Chief, Pacific (CINCPAC). (JCS) and the Commander in The peak DOD numerical strength at CASTLE was approximately as follows: Uniformed military 9,800 DOD civil servants 250 DOD contractors 60 Total personnel 10,110 Numerous technical experiments were carried out in conjunction with each of the six detonations. These experiments measured the power and. efficiency of the devices and attempted to gauge the military effects of the explosions. DOD personnel participated in this test operation as individuals whose duty stations were at the AEC design laboratories, as units performing separate experiments, and as units performing various support roles. The CASTLE operations placed almost all of the Navy sup- port group at Bikini, where its ships provided living space for personnel who were evacuated from the islands for the first test and then could not ret..cn to live there because of the potential radiation exposure. An extensive radiological safety program was instituted whose objectives were: 1. Maintenance of personnel radiation exposure at the lowest possible level consistent with medical knowledge of radiation effects and the importance of the test series.. 2. Avoidance of inadvertent contamination of populated islands or transient shipping. 2