Abstract: At approximately 12:00 p.m. on September 13, 2001, Employee #1 fractured her right elbow when she fell through an unguarded stage floor trap door opening. The accident occurred in the Performing Arts Center on the campus of Cal Poly San Luis Obispo. Employee #1 was involved in stage clean up activities and was arranging Type SO electric cords in the tool room. She went to retrieve a cord tie. The cord ties are stored in the rear right corner of the stage approximately 6 feet above the floor. The floor opening is also located in the rear right corner of the stage in the path to the area where the cord ties are stored. The opening was not guarded by a cover, attendant or guardrails. Employee #1 walked toward the tie storage area and did not see the open hole. Employee #1 stepped into the opening and fell 9 feet to the concrete floor. One witness was on the stage and saw Employee #1 dropping through the opening. The witness went to assist Employee #1 and then left for a moment to call for additional medical assistance. Employee #1's employer failed to ensure that the opening was guarded or covered. Employee #1 was taken to a local hospital to treat her fractured elbow.