Abstract: At 9:50 a.m. on February 17, 2000, Employee #1 was engaged in the leading edge construction of the plywood/concrete form work of the roof level deck at a three-story commercial building. He had picked up the end of a 4 ft by 8 ft sheet of 5/8 in. plywood and headed toward the 10 ft square depression for a column. He was walking backward and dragging the opposite end of the plywood. As Employee #1 approached the 29 1/2 in. by 32 1/2 in. floor opening for the future column, he attempted to step across it with his left foot but instead stepped into it. Employee #1 fell through the opening 17 ft 6 in. to the concrete surface of the second floor, landing head first. He was killed. Employee #1 was attempting to cover the floor hole he fell through when this accident took place. Employee #1 was selected by his employer to perform leading edge work, and he had received some training for it from his employer. He was wearing an orange vest to indicate to the safety monitor that he was designated to be in the leading edge work zone. There was a physical barrier between the typical roof deck area and the leading edge work zone. There was also a human monitor 6 to 8 ft from him, and she was watching Employee #1's actions; however, her call of warning came as he stepped into the floor hole.