Abstract: At approximately 1:00 p.m. on September 11, 1991, Employee #1 climbed on top of boiler #3, National Board #20873, permit boiler #21667-70, to close off a valve that was downstream on a non-operating fuel oil steam line. He then checked a drum vent that had recently been repaired. Boiler #3, manufactured by Combustion Engineering, had been used as an auxiliary boiler for land 2, which are larger. Over the past year, a new computerized control system was being installed in all three boilers. The #3 boiler had been up and on line for about 30 minutes. The #2 boiler had been taken out of service and four employees were working on it. At this time the #3 boiler, boiler tube #2 in the northwest corner, ruptured, releasing steam into the basement. Employee #1 was engulfed by the steam and disoriented; he descended the ladder on the northwest side of boiler #3. Employees working on boiler #2 quickly rushed over and located and removed Employee #1 from the area. Emergency response personnel were notified and Employee #1 was taken to the hospital, where he died.