Abstract: At approximately 8:45 a.m. on July 8, 1991, Employee #1 was operating a work platform inside an elevator shaft when the platform fell 15 ft. A 2 1/16 in. by 4 1/8 in. square-shaped key dislodged from the keyway on the shaft between the brake and drive pulley. This same shaft supported the winding drum for the cable which connected to the platform. The dislodged key allowed the shaft to turn freely inside the pulley when the safety controls were released in preparation for a powered descent. Employee #1 was able to release the hand-held safety, which engaged the centerline cable and stopped the platform's fall. He suffered a compression fracture of his lower vertebrae. Coworkers in an adjacent elevator shaft came to his aid and called 911.