Abstract: On September 15, 2007, Employee #1 and coworkers were working in a newly constructed 600 ft tall stack at a power plant. The crew noticed that the lighting was dimmer than usual, and Employee #1 and a coworker were sent to an approximately 203 ft high metal walkway to see what the problem might be. They used a man-hoist and an aluminum pick to reach the walkway. Employee #1 separated from his coworker and was near the end of the walkway next to a ladder when the coworker heard a loud noise. Another coworker on a lower level shouted, "Man down!" Employee #1 was found on the concrete floor; he died of injuries sustained in the fall. Employee #1 was using fall protection and was apparently tied off to a horizontal lifeline while in the hoist, but it was unclear whether he tied off to another line on the walkway. The walkway had an opening for a material hoist. When Employee #1's body was found, both lanyards attached to the right D-ring.