[Circumstances
of Incident]
The accident occurred when nitric acid delivered to a factory
by a tank truck was unloaded into the wrong tank. The tank exploded due to
a chemical reaction within the tank.
Around
5:30 in the afternoon on the day of the accident, the driver of the tank
truck carrying nitric acid arrived at the factory, handed over a delivery
slip to the employee in charge of accepting deliveries, and connected the
hose of the tank truck to the flange (for unloading).
As this was
the first time for the driver to make deliveries to this factory, his
co-worker who has delivered to this factory before told him that the
flange for nitric acid was the second from the left. However, as the
second flange from the left was made of vinyl chloride and the driver did
not think that this could be the pipe for nitric acid, the driver
connected the hose to the second flange from the right, which was made of
stainless steel.
After the connection of the hose, the employee in
charge of accepting deliveries opened the electromagnetic valve, and the
driver started the discharge. As the liquid surface of the nitric acid
tank did not rise, however, the driver checked the label of the tank and
found that he was unloading nitric acid into the tank for
triethanolamine.
The driver informed the employee in charge of
accepting deliveries of the mistake, connected the hose to the correct
flange for the nitric acid tank, and completed the unloading in about 20
minutes. When the driver was going out from the front gate, he noticed
white smoke being emitted from the tank. Around 6:25 in the afternoon, the
sub-tank and main tank for triethanolamine that were wrongly charged
exploded, releasing a chemical spill in the area.
No injuries or
fatalities were caused by this accident.
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