Abstract: Between 3:30 and 7:00 p.m. on January 17, 1991, Employee #1, a carpenter, was working alone stacking rafters at a height of 9 ft to 14 ft above the concrete floor at a site in Hayward, CA. Apparently, Employee #1 fell and injured his head, ribs, and right collarbone. There were no witnesses to the accident, and he was found at approximately 7 p.m. by a neighbor who heard groans coming from the general direction of the work site and went to investigate. Employee #1 has lost all memory of the event, so the exact cause of the accident remained uncertain. He had approximately 19 years of experience in the trade and about 10 years with the employer.