A piece of steel shrapnel hit a worker in the upper thigh, narrowly missing the femoral artery, resulting in hospitalization and surgery to repair the damage and remove the shrapnel.    The worker was replacing a track link on an excavator and used a sledge hammer to hit the pin.  A shard chipped off the pin.  When hardened steel is struck with another steel tool there is always a potential for the steel to shatter.  Once a piece of steel shatters the result  is left to chance.  The steel fragments are like bullets and result in potentially fatal injuries similar to gunshot wounds.    You could easily be hit in the eye, the groin or the hand by steel shrapnel.