site diminished rapidly after 19 July, as the emphasis shifted to preparing the devices that were to be used over Japan (1: 38). 4.1.3 Dose Summary for Project TRINITY. The dose limit for TRINITY participants was 5.0 rem (roentgen equivalent man) of gamma radiation during a 2-month period (2: 29). The table below summarizes the available dosimetry information: Summary of External Doses for Project TRINITY as of 1 May 1986 Gamma Dose (rem) Army Navy 4.2 0-0.5 05-1 1-3 3-5 5-10 10+ 103 2 15 0 30 2 10 0 1 0 1 *o OPERATION CROSSROADS. Conducted in 1946 at Bikini, CROSSROADS involved approximately 42,000 personnel, 251 ships, and 156 aircraft. The series consisted of an airdrop detonated at a height of 520 feet and an underwater shot conducted at a depth of 90 feet: Event Date Type ABLE BAKER 1 July 25 July Airdrop Underwater Yield (kilotons) 21 21 The nuclear devices were similar to the TRINITY device and to the weapon detonated over Nagasaki, Japan (3: 17). 73