Abstract: A roofing contractor was removing an old roof and putting on a new metal deck roof on a 200 by 500 foot building for the U. S. Navy. Employee #1 and a coworker had retrieved a 3 foot by 22 foot piece of metal decking and were positioning it to give to another employee who was waiting to receive it. Twelve feet of old plywood roofing had been ripped up and laid down at various locations on parts of the undisturbed roof. Some of the plywood had apparently been laid over the gypsum sublayer for footing. Four feet of the gypsum was ripped up, leaving that particular section with only rafters on which to lay the decking. As the two workers tried to position the metal decking, Employee #1 apparently slipped off some of the old plywood and fell through the gypsum wallboard to the cement floor. He died three hours later.