Abstract: Employee #1 was operating a gang ripsaw at a hardwood floor manufacturing plant when he and coworkers noticed excessive dust coming out of the machines. They concluded that the ductwork, which removed sawdust and other waste from the machines, had become clogged. The ductwork consisted of three 18 in. pipes running vertically from the woodworking machinery into a 30 in. diameter horizontal main pipe. The ductwork was suspended from the ceiling rafters using metal strapping and wood screws. The entire section, including the dust and residue inside, weighed between 200 and 300 lb. Two coworkers were loosening a section of the vertical 18 in. pipe when the main horizontal ductwork came loose from its supports and fell. Employee #1, who was standing between two stacks of lumber nearly his height, was struck on the head and then fell to the ground. He suffered a head laceration, a double fracture of his femur in one leg, and a fractured fibula and dislocated ankle joint in the other leg.