Abstract: Employee #1 was working from a flatbed truck with an articulating boom, hanging and installing Christmas tree lights on approximately 20 to 25 trees lining a driveway. The project had been in progress for between four and six hours, and the vehicle had been repositioned numerous times. At the time of the accident, it was parked on an incline and Employee #1 had the boom extended to the front quarter of the truck. The vehicle jumped the chocks and rolled approximately 50 ft down the incline before it tipped over and landed on its right side. Employee #1's head struck the pavement as the vehicle overturned, and he was killed. He was wearing a body harness but is was not attached to the bucket.