Abstract: An employee was working from a Baker scaffold, installing a fire barrier between the floor trusses of the second floor of a building. The employee was using a hammer-stapler to install the material at a position over his head and slightly away from the scaffold, which was set up with its platform about 1.2 meters above the concrete floor. In performing the job, the employee would staple about 2.5 meters of material while walking along the scaffold. When he neared the end of the scaffold, he would exit the scaffold, and unlock the caster wheels, and move the scaffold to work in the next area. At one point, the material was hanging down; and, as the employee walked along the scaffold, he misjudged the distance, walked off the end of the scaffold, and fell to the floor. In landing with his left arm extended, the employee broke his left wrist, hit his head on the concrete, and suffered a concussion.