Four men died in an explosion Thursday at a chemical plant in Japan's Osaka, Kyodo News reported.
The blast occurred at around 8:50 a.m. at a fluorine compound production plant operated by Morita Chemical Industries Co. in Osaka's
Yodogawa Ward.
The explosion occurred when the four workers were cutting away the top of a chemical tank as part of efforts to clean it. The tank stores a toxic chemical material called borontrifluoride.
The firefighters said part of the plant's roof was blown off in the blast. Two of the four victims were found collapsed on the roof of the third floor while the remaining two were found lying on the ground, the report said.
Morita Chemical Industries, an unlisted chemical maker based in Osaka's Chuo Ward, said it produces fluorine compounds for industrial use at the plant.
The chemicals are used in semiconductor production and as electrolytic solutions for lithium batteries, it said.
Usually, fluorine compounds are unlikely to explode, the company said.
Founded in 1935, Morita Chemical Industries produces and sells hydrofluoric acids, fluorine compounds and various other chemicals as well
as pharmaceutical products, the company said on its website.