Abstract: At 2:00 p.m. on November 4, 1997, Employee #1 fell through the false ceiling of a corridor down about 12 feet to the ground, landing on his back on the concrete floor. Employee #1 was hired as a fire protection sprinkler fitter. On the day of the accident, his supervisor had assigned him the job of installing the fire protection pipe and sprinklers. Employee #1 was working on the top of a corridor ceiling which was about 12 feet above the floor. At the time for the accident, Employee #1 was tightening a pipe with an 18 inch pipe wrench which slipped off the pipe and Employee #1 fell approximately 12 feet to the concrete floor and landed on his back. Employee #1 was taken to the Summit Medical Center in Oakland where he was diagnosed as having sustained muscle and ligament damage to his lower back without any fracture injuries. He was released from the hospital on the same day. Employee #1 was not wearing any fall protection, although his employer had provided him with a body harness and had told him to wear it when needed while working at higher elevations.