Abstract: At approximately 10:20 a.m. on July 19, 1990, Employee #1 was using an overhead crane to unload four I-beams from an open flatbed trailer. The trailer, which was 4 ft 6 in. high by 7 ft 7 in. wide by 41 ft 7 in. long, was parked inside building 74 with the front facing north. The two outside beams were 36 in. by 12 1/4 in. and 47 ft long, standing on the narrow dimension. At 160 lb/foot WF, they each weighed 7,520 lb. The other two beams were 12 1/2 by 12 1/2 and 40 ft 9 in. long. At 109 lb WF, they weighed 4,442 lb each. The east side at the trailer was clear and there were 3 ft high welds along and within 2 1/2 to 4 ft of the west side. While raising, blocking, and hitching alone with a pendant control, Employee #1 entered the space along the west side of the trailer and displaced the west beam, which rolled off the truck and onto him. There were no witnesses. There was no equipment failure involved.