Abstract: Employee #1 and four coworkers were attaching plywood sheeting to a truss system recently installed at a church. Three coworkers were on top doing the sheeting. Employee #1 and the fourth coworker were about 12 ft above a cement floor on a manually propelled mobile scaffold, handing up the plywood sheets. The wood "piggy back" type trusses were composed of 52 ft scissor trusses with small triangular pieces attached to their tops, forming peaks. The truss system ran along the length of the building from east and west. The sheeting was being installed on the south side of the roof when a 25 mph gust of wind came from the northwest and created a parachute effect. A crack was heard and the trusses fell in domino fashion from east to west. A falling truss knocked Employee #1 off the scaffold to the floor. He suffered a head injury and was killed. The primary cause of the accident was inadequate bracing of the trusses, as judged by the amount, size, and location of the temporary bracing (mostly 1 by 2s). The workers on the scaffold were not using fall protection at the time of the accident.