Abstract: At approximately 6:55 a.m. on June 13, 1990, Employee #1, the foreman of a three-man roofing crew, went up on the roof of a high school addition under construction to look around and to plan out his work for the day. He was the only one on the roof at the time. While walking around the roof, he went through a 17 in. by 20 in. vent opening that had been covered over by insulation the previous day. He fell 13 ft to the concrete floor, sustaining a fractured skull, a badly bruised brain, two fractured vertebrae, and various other contusions and abrasions. Causal factors related to this accident included failure to cut out the insulation over the opening to identify where it was, and failure to cover the opening as required. According to two other crew members, Employee #1 himself had put the insulation over the opening without cutting out the part that covered the hole.