Four men were killed in an explosion Thursday at a chemical plant in Osaka, firefighters said.
The blast occurred around 8:50 a.m. in Morita Chemical Industries Co.'s fluorine compound plant in Yodogawa Ward. Killed in the blast were Kazuhiro Hayashi, 47, Tomoyuki Kanazawa, 33, Tatsuya Nakatani, 45, and Keisuke Nishida, 30, police said.
The explosion occurred when the four workers were cutting away the top of a chemical tank in order to clean it. The tank stores a toxic chemical called boron trifluoride.
The firefighters said part of the plant's roof was blown off by the blast. Two of the four victims were found collapsed on a third-floor roof, while the other two were found lying on the ground.
Morita Chemical Industries, an unlisted chemical maker based in Osaka's Chuo Ward, said it makes 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 stable, the company said.
Founded in 1935, Morita Chemical Industries makes hydrofluoric acids, fluorine compounds and other chemicals, as well as pharmaceutical products, according to the company's Web site.
The plant is located in a housing and industrial complex some 1.5 km north of Shin-Osaka Station.
