Abstract: AN IRON WORKER WAS STRUCK ON THE HEAD AND BACK OF THE NECK BY A 17 INCH LONG STEEL BOLT THAT FELL APPROX. 200FT FROM THE ELEVATOR PENTHOUSE TO THE BASEMENT WHERE THEY WERE WORKING. THE IRONWORKERS WERE ASSIGNED TASK OF POTTING STRUCTURAL STEEL IN THE BASEMENT LEVEL OF THE SHAFT. THERE WAS A PROTECTIVE WOODEN DECKING BUILT APPROX 15' ABOVE THEIR WORK AREA. TWO IRONWORKERS WENT ABOVE THE DECKING TO WRAP A WIRE ROPE SLING AROUND THE GUIDE RAIL, WHICH WAS GOING TO BE USED TO SUSPEND A COME-A-LONG. TWO ELEVATOR CONSTRUCTION EMPLOYEES WERE WORKING IN THE ELEVATOR MACHINGERY ROOM (PENTHOUSE) APPROX. 200' ABOVE THE DECKING, DISMANTLING MACHINERY. A BOLT 17" LONG X 1&1/2IN.D ; WT: 10.2 LBS. WAS DROPPED THROUGH AN OPENING IN THE FLOOR WHICH FELL STRIKING ONE OF THE IRON WORKERS IN THE BACK OF THE HEAD AND NECK.