Abstract: Employee #1 was welding rebar to a beam that was positioned vertically in a trench. He was standing approximately 4 1/2 feet inside the trench, which was located at the foot of an approximately 20 percent slope. About one minute prior to the accident, a CAT model 926 wheel loader was parked on the slope, less than 650 feet from Employee #1. The unmanned loader rolled down the slope and the blade of the bucket severed his torso above the waist, killing him instantly. The driver of the loader had not used chocks when parking on an incline and he was not sure whether or not he had set the parking brakes. There was no mechanical problem with the loader's brake system, and there was no evidence that the driver used other safety precautions when parking. The bucket was lowered but not dug into the ground.