Abstract: Employee #1 and a coworker, his apprentice, were installing roof drains at a construction site. The roof decking was only partially laid and the remainder of the trusses were open. The trusses were on 48 in. centers. A ladder was leaning against a truss about 16 ft away from the decked area, and the drain they were going to work on was about 20 ft from the edge of the decking. Instead of moving the extension ladder over to the decked portion of the roof, Employee #1 and his apprentice laid some 3/4 in. plywood on top of the undecked trusses from the ladder to the edge of the decking to use as a walkway. They used a 4 by 5 piece closest to the ladder and then butted together two 4 by 8 sheets. Employee #1 started to walk out onto the plywood but, when he reached the middle section, decided it was unsafe. He was starting to turn around when the plywood on which he was standing gave way at the joint of the two 4 by 8 pieces. Employee #1 fell 15 ft to the floor and sustained injuries that required hospitalization.