Abstract: AN EMPLOYEE FELL THROUGH A 2FT.X4FT. FLOOR HOLE WHEN HE STEPPED ON AN UNSECURED DECKING PANEL HE HAD DISPLACED ON THE WAY OVER TO ANOTHER AREA. EMPLOYEE #1 WAS ON THE ROOF OF A BUILDING HELPING 2 OTHER IRONWORKERS INSTALL METAL ROOF DECKING. HE WAS TOLD TO BRING SOME DECK SHEETS FROM A SCRAP PILE ON THE NORTHWEST CORNER OF THE ROOF. ON THE WAY TO THE SCRAP PILE HE PUSHED UP A DECK SHEET THAT WAS COVERING A 4 FOOT BY 2 FOOT FLOOR OPENING. WHEN HE PICKED UP THE DECK SHEET, IT BLOCKED HIS VIEW AND HE STEPPED INTO THE OPENING. HE FELL 33 FEET TO THE CONCRETE FLOOR BELOW. HE WAS TRANSPORTED TO NORTHWEST HOSPITAL WHERE HE WAS PRONOUNCED DEAD ON ARRIVAL FROM INTERNAL INJURIES AND SPINE DAMAGE. THE COVERING ON THE OPENING WAS NOT SECURED OR MARKED. THE EMPLOYEES WERE NOT PROPERLY INSTRUCTED IN AVOIDING HAZARDOUS CONDITIONS ASSOCIATED WITH THEIR WORK ENVIRONMENT.