Abstract: A crew was cleaning the secondary ash hoppers at a paper mill. The normal cleaning procedure requires that the furnace be shut down for a minimum of 48 hours. The ash hoppers are cleaned by opening a door on the front of the hopper to allow access for the vacuum hose. Shortly before 12:00 midnight the crew attempted to clean the twelve ash hoppers, which were on the next level down. They started in the southwest corner, as was their habit. The first hopper was vacuumed out without any problems. They had been vacuuming for about 10 minutes on the third hopper when they noticed a little hot ash coming out. The employee who was operating the hose stepped back, and a large amount of ash came out. An instantaneous flash of fire, which lit up the whole area, followed. Three members of the crew exited to the north and were able to get off the platform safely. Employee #1 panicked and tried to exit to the south; unfortunately, the south side of the platform was bounded by a guardrail with one ladder for an exit. Beyond that was a sheer drop of 40 ft. Employee #1 fell to the pavement and was killed. It cannot be ascertained whether he fell over the guardrail, jumped, or fell while trying to access the ladder.