EE STATES, HE WAS STACKING 50 # BAGS OF CLAY PRODUCT ON A PALLET AND PICKED ONE OF THE BAGS UP WRONG. HE STATES HE FELT A SHARP PAIN IN HIS LOWER BACK. IT WENT AWAY AFTER AWHILE SO HE CONTINUE D TO STACK THE BAGS MORE CAREFULLY. EE DID NOT REPORT ACCIDENT TO HIS SUPERVISOR UNTIL APPROX 11:00 AM 9/19/00. EE RELEASED AND WORKED WEEK OF 9/25/00. STATED ON 10/2/00 HIS BACK WAS HURTING.