Abstract: At about 2:30 p.m. on January 27, 1998, Employee #1, a 29-year old yard worker, was seriously injured while cleaning a cement plant located at 501 "C" Street, Chula Vista, CA. He was attempting to remove some small rocks from a conveyor belt below the feed hopper with a screwdriver when the tool got caught between the belt and the end belt pulley. The engagement of the tool was so rapid and violent that it caused him to sustain a compound fracture of his left forearm. He ran to the office holding his left arm and requested assistance. Office staff called 911, and first aid was administered. Paramedics arrived in about 3-4 minutes and transported him to a local medical center. Employee #1 apparently had no special training for performing the work being performed. No records indicate that he was trained in the lock-out system instituted by the company. Employee #1 was trained in the operation of the plant and had performed this task frequently over the past 6 months. However, his employer had not provided training prior to the assignment.