Abstract: At approximately 12:00 noon on November 19, 1991, Employee #1 was replacing the front differential on a Peterbilt dump truck. The box was in the raised position with the safety bar in use. Employee #2 assisted by operating a come-a-long suspended from the dump box to hoist the differential into position. Both Employees #1 and #2 heard noises, which they had hoped were rocks rolling down the inside of the dump box. The noises turned out to be the safety bar being forced through the bottom of the elevated dump box. Because no additional cribbing or blocking had been used under the dump, the raised bed came down. Employee #1 became caught between the box and the truck frame, suffering crushing injuries including asphyxia, a separated spine, and possible internal injuries. Employee #2 jumped clear but was struck by some part of the box, suffering a laceration above his eye that required sutures.