Abstract: At approximately 9:45 a.m. on October 17, 2002, Employee #1, of Systems Automated Controls, Inc., and his electrical supervisor were discussing where to run the electric cable and where to place the electrical boxes for an overhead monorail conveyor. As they were talking, Employee #1 backed up and fell 9 ft off a platform onto a concrete floor. He suffered a concussion and fractured vertebrae in his lower back. Employee #1 was transported to USC Medical Center, where he was hospitalized for five days. The electrical supervisor said that caution tape had been placed across the unprotected edge two or three days prior to the accident. The field supervisor for Systems Engineering and Design Industries, Inc., said that he had installed the 64 in. by 80 in. platform extension about one week prior to the accident and that he had placed three strips of caution tape across the unprotected edge until a guardrail or chains could be installed. The accident occurred on Employee #1's second day at the job site. Both Systems Automated Controls and Systems Engineering and Design Industries were cited for an accident-related violation of T8CCR 1621(a).