According to police, a minimum of five people have been killed and a dozen injured after an explosion at a factory in Yokkaichi city, about 350 km west of Tokyo, Japan.
The BBC and others report that the Mitsubishi Materials plant uses highly volatile chemicals to manufacture polymers used in solar panels and cars.
"Five people are dead. Twelve people have been injured, of whom nine sustained only minor injuries," a spokeswoman for police in Mie precfecture, which takesin Yokkaichi, told AFP.
A plant spokesman said the maintenance crew was performing work on a heat exchanger used to make silicon items.
According to the BBC, industrial deaths in Japan stood at about 1,000 a year in 2010, way down on about 2,500 a year in 1990 though still higher than for many western nations.