Abstract: At approximately 12:45 p.m. on October 4, 1990, Employee #1, a foreman, was preparing to remove a portion of the old call box system on the upper deck of the San Francisco Bay Bridge. He was working from the elevated bucket of a 48 ft boom truck while an apprentice electrician acted as groundsman. Employee #1 raised the bucket and accidentally pinned his right hand between the operating levers and a steel beam. He yelled to the groundsman to operate the safety override at the base of the truck, but the groundsman was unable to do so. Employee #1 then told the coworker to back up the truck to free his hand. For the truck to reverse, its front wheel had to go over a curb, further raising the bucket. Employee #1 sustained crushing injuries to his hand and his little finger was amputated.