WHILE BACKING OUT OF ROTOPACKER BLDG W/FORKLIFT, EE BACKED FORKLIFT INTO BLDG SUPPORT CROSS BEAMS. THE IMPACT JARRED HIS NECK & HE HIT HIS HEAD ON STEERING WHEEL. HE DID HAVE HARD HAT ON BUT T HE IMPACT CAUSED THE ADJUSTMENT KNOB ON HAT TO BREAK & HAT FLEW OFF. HE HAD A LACERATION ON THE TOP OF HIS HEAD THAT REQUIRED STITCHES.