EE WAS SETTING ON THE BACK OF AN MTI 350 MUCKER HANGING PIPE. THE PIPE WAS SUPPORTED ON ONE END BY A CHAIN AND THE OTHER END WAS RESTING ON THE MUCKER HOOD. HE REACHED BEHIND HIM WITH HIS LEFT HAND AND GRASPED THE PIPE, LIFTING IT OVER HIS LEFT SHOULDER. AT THAT TIME HE FELT A SHARP PAIN IN HIS LOWER BACK.