Abstract: Employee #1, an oil rig hand, was helping off-load a skid-mounted bull pump from a lowboy trailer. A truck driver backed oil field truck #2 to within 15 ft to 20 ft of the rear of the lowboy, set the brakes, and left the transmission in neutral and the power takeoff in third gear. The truck was equipped with a bed winch and the driver was operating the winch controls while Employee #1, with his back to the trailer, was pulling on the winch line. The plan was to use the truck's winch line to pull the pump far enough off the trailer so that it would slide off when the truck attached in front of the trailer was driven forward. This was common practice in the oil fields. Another coworker was in the cab of the truck attached to the lowboy trailer and he decided to try to shake the pump off by driving backward and hitting the brakes. This was also a common practice in the oil fields for unloading large items equipped with skids. The second coworker had not seen the first truck drive up behind the trailer. When he backed up the trailer to jog it, Employee #1 was crushed between it and the back of the first truck. The crew was not using a spotter. The second coworker later stated that he had performed a walk-around of the trailer; but had done the walk-around about five minutes before he started backing up and before the first truck arrived.