Paper mill dust explosion,Akabira, Hokkaido, Japan
February 5, 1995
Paper powder accumulated in the duct of the dust collector at
the paper mill. Paper powder floated in the air in the paper machine
room, and the humidity was low. The powder ignited during normal
work, and the paper powder exploded. A dust explosion of suspended
particulates indoors spread. Insufficient environmental management
seems to be the cause. Paper powder ignited during operations
to wind a roll of paper at a paper mill, and paper powder exploded.
Suspended particles in the room also exploded
1. At a paper mill, a cylinder of a cutter that cuts off a base-sheet
from a dryer of a paper machine in a paper machine room was operated
with air pressure.
2. Next, the cutter that tears off the base-sheet from the dryer
of the paper machine was to be operated. At this time, paper powder
in a dust collector of the system ignited, and the paper powder
3. Combustion was propagated with suspended dust in the room,
and the explosion spread to whole the paper machine room.
The ignition source has not been specified. As paper powder had
accumulated over a long time, it had dried and been carbonized,
and could ignite. Or, the following is considered as anignition
source: static electricity or contact sparks of a cutter and a
paper machine. Accumulation of paper powder in the dust collector
and a dust cloud in the paper machine room were the causes of
the explosion. In addition, the humidity in the room was low at
15% or less.
Paper is combustible, and a dust explosion of paper powder can
occur. It is necessary to treat solid material that generates
powder as carefully as the vapor phase of a dangerous liquid.
1. The capacity of the dust collector was insufficient, and dust
accumulated in the duct of the dust collector.
2. Measurement of the work environment was not taken. It was not
certain whether the concentration of floating dust in the room
was appropriate, or whether the humidity in the room was controlled
3. Basically, there seems to have been a lack of investigation