EMPLOYEE WAS WALKING EAST THROUGH THE 31.5/31.7 CONVEYOR TUBE. JUST AS HE WAS PASSING THROUGH THE ACCESS DOOR LEADING TO THE TRANSFER TOWER #2 BUILDING, HE HIT HIS HEAD ON A LOW-HANGING PIPE. HIS HARD HAT WAS KNOCKED OFF AND HAD NECK PAIN. HE WAS EVALUATED BY A DR. AND PHYSICAL THERAPY WAS STARTED 9/20/01.