Abstract: Employee #1 was assigned to install a corrugated sheet metal roof on a "butler" warehouse. The finished roof was 61 feet by 100 feet, and the slope of the ground to the leave height of the roof was approximately one in ten. Six employees installed the sheets on the roof. The peak of the roof had a 22-inch gap. A heavy rainstorm began, and the employees suspended their work. The employees returned to work once the rain storm let up. Employee #1 attempted to step across the gap. As he stepped across, he lost his footing because of slippery conditions. Employee #1 fell through the gap and struck Employee #2, who was working on the concrete slab below.