Abstract: On February 3, 1999, Employee #1 was helping a co-worker mount a stinger to a caterpillar loader. The stinger, which an attachment used for track equipment work, weighed about 800 pounds. The stinger had been rotated 90 degrees and was lying on its side. The base of the stinger is a 3-ft by 3-ft steel plate that is 1 inch thick. Attached to this plate was a long pole-like device with a hook on the end. The base plate had two hooks on it, to accommodate the front loader arm. The driver of the loader moved the loader up to the edge of the stinger base plate, intending to roll the stinger to its upright position so that it could be mounted on the loader. As the driver applied pressure to the stinger, the hook end lifted and the stinger boom rotated toward Employee #1, who was inside the circle of rotation. Employee #1 was struck and seriously injured by the fast-moving stinger. The employee was hospitalized at the San Bernardino County Hospital, where he had surgery for his injuries.