EMPLOYEE WAS MOVING A 50# BAG OF BARIUM CARBONATE FROM THE PALLET TO THE TABLE WHERE IT IS STORED, A DISTENCE OF ABOUT 12 FT. WHEN HE PICKED UP BAG AND TURNED, HE FELT A PAIN IN HIS BACK. EMPL OYEE SAID THAT HE POSSIBLY TURNED HIS UPPER BODYBEFORE MOVING HIS FEET.