INVOLVED IN A 2 MAN PROCESS OF CHANGING OIL DRUM. NO LIFTING REQUIRED, HOWEVER, AFTER THE PROCESS WAS OVER HE FELT TIGHTNESS IN LOWER BACK. STATES IT WENT AWAY WITH MOTRIN AND DID NOT FEEL THAT IT WAS NOTEWORTHY. AS TIME WENT ON STARTED HAVING GRADUAL ONSET OF INCREASED DISCOMFORT. REPORTED NEED FOR MEDICAL EVALUATION ON 9/10/04.