Abstract: THE DRILL CREW HAD BEEN REMOVING THE DRILL STRING FROM AN OIL AND GAS WELL PRIOR TO RUNNING CASING. THE CREW WAS REMOVING THE DRILL COLLARS A UNIT AT A TIME. THE COLLAR WAS SUSPENDED FROM THE ELEVATORS, AND THE FREE END WAS ATTACHED BY A SLIP LINE THAT WAS CONNECTED TO A PNEWMATIC WINCH. THE FREE END HAD BEEN PULLED TO THE V-DOOR WHEN THE SLIP LINE CAME LOOSE FROM THE HOOK. THE COLLAR SWUNG BACK TOWARDS THE ROTARY TABLE AND STRUCK EMPLOYEE #1 IN THE BACK OF THE HEAD AND SHOULDER. THE EMPLOYEE HAD BEEN WARNED NOT TO STAND NEAR THE ROTARY TABLE UNTIL THE END OF THE COLLAR HAD BEEN LOWERED BELOW THE FLOOR LEVEL AND OUT THE V-DOOR.