EE WAS OPERATING BAGGER FILLING 50# PAPER BAGS WITH KAOLIN CLAY. BAG BURST GETTING CLAY IN EYES. WHEN EMPLOYEE ATTEMPTED TO REMOVE BAG FROM MACHINE HE ACCIDENTLY ACTIVATED THE MACHINE CAUSING IT TO DISCHARGE CLAY ON HIM. HE LOST BALANCE AND FELL BACKWARDS HITTING HEAD ON WALL & LANDING ON BACK. HE SAID HE WAS OK BUT SORE & WANTED TO BE CHECKED. HE WENT TO HOSP, X-RAYED & GIVEN RX.