Abstract: AT APPROXIMATELY 6 PM ON MARCH 23, 1987, EMPLOYEE #1 ENTERED AN ULTRA PURE STAINLESS STEEL TANK, STILL UNDER CONSTRUCTION, INTENDING TO USE A HAND-HELD NITROGEN-SUPPLIED AIR HOSE TO DRY THE INTERIOR SUFACES OF THE TANK. ANOTHER EMPLOYEE, NEWLY HIRED, WATCHED EMPLOYEE #1 FROM OUTSIDE THE TANK. THE TANK WAS APPROXIMATELY 12.2 FEET LONG AND 5.5 FEET IN DIAMETER, WITH A 1.5 FOOT CYLINDRICAL ENTRANCE/EXIT. AFTER SEVERAL MINUTES, EMPLOYEE #1 LAY DOWN INSIDE THE TANK WITH THE NITROGEN STILL COMING OUT THE HOSE. A THIRD EMPLOYEE HAPPENED TO PASS BY AND ASKED THE SECOND EMPLOYEE WHERE EMPLOYEE #1 WAS AND WHAT HE WAS DOING. THE THIRD EMPLOYEE THEN SAW EMPLOYEE #1 LYING DOWN IN THE TANK. HE TOLD THE SECOND EMPLOYEE "WE HAVE TO GET HIM OUT". AS THE THIRD EMPLOYEE TURNED AWAY FOR A FEW SECONDS THE SECOND EMPLOYEE (EMPLOYEE #2) ENTERED THE TANK. HE COLLAPSED IN ONLY A FEW MOMENTS. THE THIRD EMPLOYEE AND A HELPER WERE ABLE TO PULL EMPLOYEE #2 OUT OF THE TANK BY PULLING HIM BY HIS HAIR FROM OUTSIDE THE TANK. THE FOURTH EMPLOYEE DONNED A SCBA AND RESCUED EMPLOYEE #1 FROM THE TANK. EMPLOYEE #1 DIED. EMPLOYEE #2 RECOVERED COMPLETELY. THERE WERE NO RESPIRATORS AT THE TANK PRIOR TO ENTRY. EMPLOYEES #1 AND #2 WERE UNTRAINED IN THE HAZARDS OF WORKING WITH NITROGEN GAS (OXYGEN DISPLACEMENT). EMPLOYEE #1 HAD DONE SIMILAR WORK ON ONE PREVIOUS OCCASION. AT THAT TIME HE HAD WORN APPROPRIATE RESPIRATORY GEAR.