Abstract: Employee #1 and a coworker were members of an eight-person crew working on the roof of an addition to a manufacturing plant. They were installing 3 ft wide rolls of 3 in. thick vinyl-backed insulation, which were then covered with 3 ft wide by 25 3/4 ft long roofing panels for a screw down P.B.R. (purling bearing rib) metal roof. A 3 ft wide by 10.666 ft long opening for a skylight roof panel had been covered with insulation and with a temporary solid roof panel that was 25 3/4 ft long. Work was moving along toward the north and two more 3 ft solid panel runs had begun north of the 3 ft wide run that contained the temporary covered skylight. Employee #1 and a coworker removed the temporary solid sheet that covered the skylight, intending to use it in one of the two runs north of the skylight opening. While talking to his coworker and unrolling insulation, Employee #1 stepped backward and fell through the insulation that still covered the skylight opening, Employee #1 fell 31 1/2 ft to the concrete and died.