Abstract: On the evening of September 26, 1995, Employees #1, #2, and #3 were attempting to install an A/C heating duct 25 ft 3 in. above a future gymnasium floor. Employee #3 was working from the platform of a manually propelled rolling scaffold 25 ft 6 in. high. Employee #1 was working from a 6 ft wooden stepladder on the platform of another manually propelled scaffold 15 ft 10 in. high. Employee #2 was on the floor to move the scaffolds when needed. Using a chain fall, Employee #3 raised the 42 in. diameter elbow end of the 25 ft long double walled duct to match the existing duct at 25 ft 3 in. He then attempted to line up the two ducts and fasten them together. The 16 gauge, 3 in. wide hanger/hoisting strap around the elbow broke, causing the heavier elbow end of the duct to fall. This section struck the scaffold on which Employee #1 was working, causing it to tip over. He fell with the scaffold, then jumped clear of the falling scaffold and duct. He landed on his feet then fell onto his right side. Employee #2 was struck in the back by an unknown object and knocked to his knees. The investigation revealed that the strap attached to the elbow section comprised two pieces of 16 gauge galvanized metal 3 in. wide that were spot or tack welded together by the manufacturer. The weld broke and the bolt holding the strap to the duct pulled through the strap. The duct should have been secured and lifted with a hoist rather than with the permanent installation hangers.