also at HARDTACK I were authorized to receive 15 rem for the total operation (21: 5,74). The table below summarizes doses for both the weapons-related events and the safety experiments: Summary of External Doses for Operation HARDTACK II as of 1 May 1986 Gamma Dose (rem) 0-0.5 0.5-1 1-3 3-5 5-10 10+ Army 45 64 200 15 5 1 Navy 31 0 1 1 0 0 204 19 27 5 2 0 2 0 0 0 0 0 952 35 20 2 0 0 Air Force Marine Corps Civilian DOD Participants 4.18 SAFETY EXPERIMENTS. The nuclear weapons testing program included 33 safety experiments, conducted at the NTS from 1955 to 1958 (22: 8,9,11,12; 17: 9): e Four experiments called PROJECT 56 and conducted in November 1955 and January 1956, after Operation TEAPOT e Six experiments called PROJECT 57 and conducted in April, July, August, and September 1957 before and during Operation PLUMBBOB e Four experiments identified as PROJECT 58 and conducted in December e Nineteen experiments conducted from July to October 1958 during Operations HARDTACK I and II. 1957 and February and March 1958, after Operation PLUMBBOB Eleven of the tests were surface detonations, while nine occurred in shafts, six in tunnels, and one on a barge. Of the remaining safety experiments, five were tower detonations and one was a balloon test. Ten of the experiments had no measurable yield while one, COULOMB C, had 0.5 kiloton, which was the highest yield of any safety experiment. 128