Abstract: Employee #1 was working from an aerial lift preparing to weatherproof a joint at the southwest corner of a retail building. The lift was struck by an unmanned concrete truck, and the employee was thrown from the lift platform. The concrete truck driver had parked the vehicle approximately 130 ft from the building on an inclined road at the southwest corner. The driver left the truck without chocking the wheels and walked toward the portable toilets located on the west side of the building when he heard the vehicle moving down the incline toward the aerial lift. The concrete truck struck the aerial lift. Employee #1, who had not been wearing the supplied safety harness, was thrown from the aerial lift and died at the scene.