23 December 1995




SAIC (E. Ortlieb)


Radiation Dose Assessment Operation Castle (1954)

BACKGROUND (References 1, 2)

Operation Castle comprised six nuclear weapon tests conducted at the Pacific Proving Ground (PPG) between 1 March and 14 May 1954. The PPG, located in the Central Pacific Ocean area, consisted of the land areas, lagoons, and water areas within three miles of two Marshall Islands atolls, Enewetak and Bikini. Bikini Atoll is about 2200 nautical miles southwest of Hawaii, and Enewetak Atoll is about 195 nautical miles west of Bikini Atoll. The principal objective of Operation Castle was to test high-yield thermonuclear devices. All but the last were detonated at Bikini.

UNIT AND PERSONAL ACTIVITIES (References 1 through 4)

First Lieutenant was the Officer in Charge (OIC) of the Traffic Analysis Section of the Communication Security Detachment (Comm Sec Det), 8600 Administrative Area Unit, at Operation Castle. He arrived at Enewetak with the unit on 17 December 1953 by air transport from Travis AFB, California, and departed the PPG from Enewetak on board USNS FRED C. AINSWORTH (TAP 181) on 14 May 1954. The veteran was detached for return to his home station when AINSWORTH arrived in San Francisco on 27 May 1954.

While at PPG, unit personnel were stationed at various times on Enewetak, Bikini, and USS ESTES (AGC 12). Reference 4 includes a statement by the veteran indicating that he was on temporary duty (TDY) from Enewetak to Bikini until March 1954, “…or the big shot,” and that at some time during the operation he was aboard a “communication” ship. These recollections are consistent with CASTLE documentation. As of 1 March 1954, 24 of the 34 unit personnel, including the veteran, were stationed at Enewetak Atoll (as per communication from CO, Comm Sec Det, to Rad Safe Officer, 18 March; in Reference 4); the 10 at Bikini had evacuated for Shot BRAVO aboard ESTES on the previous day. As Bikini was too radiologically contaminated by BRAVO to permit remanning, the detachment remained aboard until the unit departed the pro. Reference 3 states that the personnel of the unit were rotated frequently between Enewetak and ESTES but that a rank and MOS balance was retained. There is no direct evidence available of the veteran’s rotation, but there was another lieutenant with his MOS.

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