Abstract: Employee #1, a carpenter, was working alone about three units away from the rest of the work crew. He was nailing particle board on the front wall framing, which was lying flat on the first floor. The framing was partly covering the stairway floor opening to the basement, leaving an uncovered area of about 5 ft by 37 in. Employee #1 apparently lost his balance or tripped and fell 9 ft to the concrete basement floor. He sustained a concussion and has no memory of the accident or what he was doing before the accident. The memory loss continued for the next two weeks. Employee #1 is still hospitalized.