An explosion at an iron factory in Asahikawa, Hokkaido, on Tuesday morning killed the manager and left five people injured, police and firefighters said.
The 56-year-old manager, Akira Sato, died at a local hospital after suffering serious burns from the 8:30 a.m. blast at Hiyama Iron Works Co. Fifteen other workers were also taken to the hospital, with five men confirmed to have sustained injuries.
The explosion occurred near a furnace after melted steel may have inadvertently come into contact with the coolant water and triggered a vapor explosion, the police said.
All 16 workers were inside the factory at the time.
The blast shattered windows and left a hole in one of the factory walls, the police said. Nearby residents and workers evacuated the area after the accident.
The factory is located about 2 km from JR Asahikawa Station. Hokkaido Railway Co. said it suspended some train operations.
A 60-year-old man said he heard two loud noises and felt his building shake. "When I looked outside, black smoke was coming from the iron factory," he said.
Hiyama Iron Works, launched in 1923, manufactures iron frames for construction, molds and industrial machinery.