Abstract: At about 11:00 a.m. on October 24, 1991, Employee #1 and five coworkers, of Delta Steel Erectors, were installing a girt above the second floor on the perimeter of the southwest section of a newly constructed building within the Chevron USA, Inc., refinery in Richmond, CA. A crane was unable to reach this section; consequently, a block and tackle was used. Employee #1, standing on a lower girt, placed his lanyard snap on the lip of the existing girt, 4 ft on center of his feet. As he removed the nut and pulled the bolt to receive and place the new girt on top of the existing girt and its support, the existing girt came off the support. Employee #1 lost his balance and, being unsecured to a substantial member of the structure, fell approximately 50 ft to the concrete floor and was killed.