In the technological competition to achieve clearer
printing, manufacturers are developing finer toner particles,
increasing the risk of dust-induced explosions.According to the
Kanagawa prefectural police, on Jan. 7, a recycling plant of
waste-disposal company T’s Future Co. in Hadano, Kanagawa Prefecture,
burst into flames. The fire destroyed about 1,100 square meters of the
plant, injuring three male employees.

On Aug. 28, a toner
cartridge pulverizer exploded at a recycling factory in Kanazawa Ward,
Yokohama, severely burning a man who was operating the
machine.According to investigators, leftover toner contained inside a
cartridge is believed to have dispersed in the air as a photocopier
machine and other devices were being compressed in a crushing machine.
A dust explosion then apparently occurred when scattered toner
particles reacted with oxygen and caught fire.

According to a
major photocopier manufacturer, toner particles made of plastic and
other materials have been minimized to as small as five micrometers
(five thousandths of a millimeter) in the past few years.As if tracking
the industry improvements in photocopy cartridge toner quality, dust
explosions occurred at a recycling plant in Owariasahi, Aichi
Prefecture, in 1999, and at a toner manufacturing plant in Hirakata,
Osaka Prefecture, in 2003. In both cases, the explosions were
determined to have been caused by toner, bringing the risk to light.

Some
recycling plants are equipped with a toner dust collector and an
explosion control device that sprays a fire extinguishing chemical, but
companies and plants are not required by law to employ the measures.The
plant in Hadano, Kanagawa Prefecture, was equipped with a dust
collector, but did not have explosion control equipment in place.