Abstract: Employee #1 and coworkers were installing a 40 ft diameter, 350,000 gallon stainless steel storage tank with seven panels that had to be bolted together and welded in place. They were installing the sixth panel, and Employee #1 was bolting it to the existing ones. He was in a bosun's chair that was being hoisted by a crane to the catwalk at the top of the tank panel when he became entangled in the lift sling and chair. He tried to swing it over his head to clear himself, but the sling cable opened the latch of the crane hook and it became unhooked. Employee #1 lost his balance and fell approximately 38 to 40 ft to the ground. He was killed.