Abstract: On October 13, 2006, Employee #1, a foreman, was working on the wall of a laboratory room at the University of California-Davis. He moved a rolling scaffold into one corner of the room to reach the top of the wall. He positioned the scaffold with one wheel resting on a plywood cover that had been placed there by the primary contractor to cover a floor opening. After locking the wheels of the scaffold, Employee #1 ascended the scaffold and began to work on the wall. Upon completing the job he was starting to descend when he felt the scaffold begin to fall forward, causing him to lose his balance. Employee #1 fell to the floor and suffered a fracture to the left side of his skull, fractured ribs on his left side, and a fracture to the end of his right thumb. Emergency medical personnel responded and Employee #1 was transported to the University of David--Sacramento, where he was hospitalized for four days. Subsequent investigation determined that the plywood cover had shifted and the scaffold wheel had fallen into the hole it was covering.