Abstract: AN EMPLOYEE OF A CONSTRUCTION FIRM WAS STANDING ON AN ALUMINUM LADDER USING AN UNGROUNDED ELECTRIC SCREW GUN. THE TOOL WAS CONNECTED TO PERMANENT WIRING THROUGH A FLAT, UNMARKED, THREE-WIRE EXTENSION CORD SET THAT WAS ALSO UNGROUNDED. THE TOOL WAS NOT CONNECTED TO A CIRCUIT PROTECTED BY A GROUND-FAULT CIRCUIT INTERRUPTER, AND THE EMPLOYER DID NOT HAVE AN ASSURED EQUIPMENT GROUNDING CONDUCTOR PROGRAM. EVEN THOUGH THE EMPLOYEE WAS AWARE THAT ANOTHER WORKER HAD RECEIVED AN ELECTRIC SHOCK FROM THE SCREW GUN, THE EMPLOYEE CONTINUED TO USE IT. THE EMPLOYEE WAS ELECTROCUTED BY AN APPARENT GROUND FAULT IN THE TOOL.