WHILE WORKING ON A BEARING RACE THE EE WAS USING A HAMMER TO LOOSEN THE BEARING. WHILE STRIKING THE BEARING RACE THE METAL ON METAL ACTION CAUSED A PIECE OF METAL APPROX.1/4"" IN SIZE TO BREAK AWAY & STRIKE THE EE IN HIS RT. FOREARM, PIERCING THE SKIN. THIS REQUIRED 4-5 STITCHES.