Abstract: Employee #1, working with a company rigging up a triple oil field drilling rig, was staking out the layout and marking the locations of various parts of the drilling operation (e.g., mud pit, water pond). A large oil field truck, which had just unloaded the draw works on the rig floor, came down the loading ramp off the rig floor. The truck was backing out of some fairly tight quarters so equipment could continue to be moved on the right side. Employee #1, who was last seen standing near the right front side of the vehicle, was killed when the truck rolled over his back, causing injuries to the upper chest area. Neither a back-up alarm nor guide(s) were present at the time of the accident.