Water entering a furnace is believed to be the cause of this afternoon's explosion at Exide Technologies' battery factory in Lower Hutt which caused minor damage and no injuries.
The blast, reported just after 1pm, blew out about eight windows at the Petone factory and created a fire that was quickly put out, said Exide spokesman Mark Unsworth.
"Preliminary investigations are that it was a steam explosion caused by some hot material from the furnace meeting up with some water somehow," he told NZPA.
The factory is the country's only battery recycling plant and the furnace melts car and truck batteries.
There was no chance any emissions or dust escaped from that area of the factory, he said.
The plant manager was closest to the furnace at the time and was unhurt.
The Department of Labour was inspecting the cause of the blast.
