An explosion Tuesday at a chemical factory near Osaka injured at least two people, local officials said.

The explosion occurred in the manufacturing area of the chemical factory and warehouse complex in the suburb of Higashi-Osaka, according to fire official Michinobu Inoue. The complex is operated by Osaka-based Meiwa Kagaku Kogyo Co., he said.

The blast occurred around 1:37 p.m., according to police official Toyoki Nishimura. Footage from the site broadcast around 10 minutes later on NHK showed a thick column of black smoke pouring from the building amid continued intermittent explosions.

Two male plant workers, aged 30 and 37, were seriously injured and taken to a hospital, where they were placed in the intensive care unit, Inoue said.

Fire officials believe aluminum powder used at the factory exploded, Inoue said.

The powder is used as a heating agent for casting aluminum, a Meiwa Kagaku Kogyo official who refused to identify herself said.