Abstract: Employee #1 and a coworker are employees of Peterson Concrete. They were preparing for the next concrete pour on the second floor of building #10. They were laying the wire mesh for the concrete. There was a large sheet metal elbow on the floor, which they picked up. As they started to move with it, Employee #1 stepped through a hole that the elbow had been covering. Employee #1 fell through the hole and entered a duct that carried him 30 feet 10 inches through the first floor to the basement. Employee #1 suffered serious back injury. As a result of the action that Employee #1 and a coworker took in uncovering the opening, a serious accident occurred. The following is a quote from the construction standards: 1926.500(b)(1) "Floor openings shall be guarded by a standard railing and toeboards or cover, as specified in paragraph (f) of this section. In general, the railing shall be provided on all exposed sides, except at entrances to stairways." Because the floor opening had been covered until the accident happened, a citation will not be issued.