EE WAS REMOVING A PIECE OF WEAR METAL FROM A WA-600 KOMATSU BUCKET. HE WAS USING A SLEDGE HAMMERTO HIT THE PIECE OF WEAR METAL IN ORDER TO KNOCK IT IN TO THE RELEASE POSITION. THIS WAS A SPARE LOADER BUCKET AND WAS SITTING ON THE YARD. IT WAS SLIGHTLY WEATHERED AND RUSTY. WHILE HITTING THE WEAR METAL WITH THE SLEDGE HAMMER A PIECE OF METAL BROKE OFF & PUNCTURED/LODGED IN HIS SHIN.