Abstract: Employee #1, newly hired by Yellow Freight, was being trained by a lead person. They were cleaning the area below the loading dock of a 200-door truck terminal. The trailers had been pulled about 15 ft away from the loading dock to facilitate cleaning. When the lead person had finished at the area near the #36 door, he told dispatch that the trailer could be pushed back to the dock. Employee #1, who was working at the #57 door area, suddenly went to the #36 door to retrieve a piece of plywood that was lying on the dock. He was injured when he became pinned against the dock by the trailer that was being pushed back into it.