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Explosion at surface treatment furnace for automobile components
|[Circumstances of Incident]
This accident occurred at a continuous-type furnace used to carbonize the
surface of steel plates in the automobile manufacturing factory.
In this process, steel plates are heated up to around 900°C in a continuous-type
gas furnace and the steel plate surface is carbonized. The carbonized steel
plate is then hardened through a heat treatment process.
The operation of the furnace where the accident occurred was totally stopped
on December 30 for the year-end and new-year holidays. As it was necessary
to increase the temperature inside the furnace to the prescribed temperature
on the previous day in preparation for the start of operations on January
8 in the new year, some workers came to work. Victims A and B ignited burners
by using an ignition torch one by one from around 8:45 in the morning.
When they were about to ignite burners Nos. 26 and 27, they stopped the
ignition because of the smell of gas. When they resumed the ignition after
ventilating the area, there was a loud bang with flames and hot air emitted
from the door at the exit side of the furnace.
Because of this, victims A and B suffered second to third degree burns
on their arms, legs, faces, etc.
The following can be considered as the causes of this accident.
- Combustible gas was contained in the nitrogen gas that was injected in
the system for replacement before suspending continuous-type furnace operations
for year-end and new-year holidays.
- Although the standard work manual required opening the furnace doors before
ignition to exhaust the remaining gas, this was not implemented.
- Although the standard work manual dealt with furnace ignition, a decrease
in furnace temperature, gas replacement, etc., these specifications were
not fully implemented by the workers concerned.
|[Type of accident]
|[Number of victims]
|Two injured (requiring an absence from work)