EE WAS REMOVING THE DOOR SHIM PIN FROM A SHOVEL BUCKET. HE HAD A NYLON STRAP ATTACHED TO THE PIN& TO THE BOOM ON HIS SERVICE TRUCK, PUT TENSION ON THE STRAP BUT THE PIN DIDN'T PULL FREE. THEN HE REMOVED HIS WELDING HELMET BUT DIDN'T PUT ON HIS HARD HAT. HE STRUCK THE PIN WITH A PRY BAR & IT RELEASED STRIKING HIS HEAD & CAUSING A LACERATION THAT REQUIRED 8 SUTURES TO CLOSE.