Abstract: At approximately 8:15 a.m. on August 21, 1987, Employee #1 was on a roof helping to set skylights. He and a coworker had just set one in place and the coworker was nailing it down. Employee #1 had moved to the next skylight location and was removing the cover from the 22 1/4 in. by 46 1/4 in. opening when he fell 15 ft 9 in. through it to the concrete floor. Before reaching the floor he fell across a steam cleaning machine that was sitting below the skylight opening. This took his feet out from under him, causing his head to strike against the floor. He was hospitalized with severe head injuries. There were no eyewitnesses on the roof and no cause for the accident has been determined. Employee #1 apparently slipped, lost his balance, or both.