Abstract: On June 24, 2007, Employee #1 and two coworkers were installing the prefabricated exterior wall sections on the second-floor deck of a new, single-family house under construction. There was a wall section that had windows cut into it that was lying across the deck, partially covering the second-floor stairway opening. There were no stairs in place from the first floor to the second floor, and there were no railings around the floor opening. One of the workers was dragging a section of wall over the piece lying on the deck when the piece being moved became wedged. Employee #1 came over, picked up the stuck section, and helped the worker carry it. While moving that the piece of wall, Employee #1 stepped into the window opening of the wall section that was lying over the floor opening. He fell approximately 15 ft through the window opening and past the first floor deck, and landing almost halfway down the stairs from the first floor to the basemen. Employee #1 suffered rib fractures and a collapsed lung, along with contusions and sprains.