EE WAS OPERATING A HYDRAULIC PIPE BENDER AND HAD JUST FINISHED BENDING A SECTION OF PIPE CONDUIT. AS A COWORKER PULLED THE PIPE OUT AND AWAY FROM THE BENDER, THE FRAME RAIL PIN SLIPPED OUT OF POSITION. ONCE THE PIN HAD SLID BACK AWAY FROM THE RAIL POSITION IT ALLOWED THE HYDRAULIC CYLINDER TO FALL FORWARD STRIKING EE ON HIS LEFT SHOULDER.