Abstract: At approximately 1:33 p.m. on January 9, 1985, Employee #1 was working on the 4:12 pitched roof of a two-story, single family dwelling with a ground-to-eave height of 17 ft 11 in. He was applying 30 lb felt roofing paper and fiberglass shingles over 1/2 in. plywood sheeting. A 42 1/2 in. square skylight opening above the interior stairwell had been temporarily protected with two pieces of 2 by 4 lumber, nailed in the opening approximately 14 1/2 in. apart and then covered with the felt paper to temporarily waterproof the dwelling's interior. The opening was outlined and its edges were marked with three pieces of unnailed 1 by 4 lumber that were laid flat: two pieces were placed on the opening sides and one piece was placed on the bottom slope opening. While walking on the roof, Employee #1 stepped on the piece of lumber marking the bottom slope side, slipped, and fell head first through the opening, breaking one of the 2 by 4s across the skylight. He fell approximately 20 ft 10 in. onto a concrete floor at ground level and was killed instantly.