establish a safe time for personnel to recover instruments and test data near the burst. At about six (6) hours after the detonation a second heli- copter transported a rad-safe team around the shot atoll to accomplish a more detailed radiation check and to assess the damage to airstrips and helicopter pads. Following test events, all aircraft returning to Eniwetok which could possibly be contaminated were monitored and those requiring decontamination were isolated. The aircrews were immediately sent to the personnel decon- tamination center, checked thoroughly and decontaminated when necessary. Contaminated aircraft were allowed to decontaminate themselves in isolation by radioactive decay when time permitted. This technique insured a minimun of radiation exposure to the decontamination personnel since the contamination intensities approximately halved themselves each seven (7) hours. After decay the remainder of the contamination was removed from the aircraft through normal washing with chemicals, water and high pressure hoses, . Many activities under Task Group 7.) participated in the accomplishment of a successful and a safe nuclear test. Through the planning and adminis- tering of a conservative yet realistic radiological safety program, Operation HARDTACK was completed with no radiation injuries occuring within . Task Group 7.4 140 ates fun