EMPLOYEE WAS DRIVING FORKLIFT ON FURNACE FLOOR AND FORKLIFT CAME TO A SUDDEN STOP. FORKS WERE TOO LOW AND HIT FLOOR EXPANSION JOINT CAUSING EMPLOYEE'S HARD HAT TO HIT ROOF AND EMPLOYEE BITE LO WER LIP. EMPLOYEE REQUIRED 5 STITCHES AND THEN WAS PREVIOUSLY SCHEDULED OFF FOR 4 DAYS.