Spontaneously combusting tea towels caused a fire at a laundromat overnight.
The fire engulfed the Auckland laundromat at about 2.30am, extensively damaging the Sandringham business and a dental surgery upstairs.
The cause of the blaze at the two-storey building was unusual, but not unprecedented. Massage parlours drying cloths that had soaked up oil had sometimes experienced spontaneous combustion phenomena too, said Mike McEnaney of the New Zealand Fire Service.
Mr McEnaney, a specialist fire investigator, was at the scene of the fire today.
"What we've determined is, it's spontaneous combustion, self-heating as a result of some tea towels that have been through the laundromat. They've been through the washing process, then drying, and then they've been put away [when] they haven't cooled down enough," he said.
The tea towels came from a restaurant. They were washed, dried, then put in a plastic bag for the client to collect.
Mr McEnaney said the client did not collect the towels. It appeared the bag had no airflow, the dishcloths heated up, and later ignited.
He said the event was unusual but hot, dried tea towels at a cafe elsewhere in Auckland caused a similar fire a few weeks ago. Mr McEnaney said oil residues were usually a critical component in such fires igniting.
"It's a bit common in massage parlours, because they use a lot of oils," he said.
"If you use oils, and you don't wash in hot water, and you leave a bit of impregnation of oil in it, then you put it in a big dryer and dry it, then you fold them up and put them away while they're still hot, they have the ability to continue to heat up. And then they self-combust after a while."
Mr McEnaney said similar events could happen at home but usually domestic tumble dryers had a cool-down cycle, which the Fire Service strongly encouraged people to use.
He said the Sandringham laundromat would be "out of action for a while" and he suspected the dental surgery would perhaps be closed for a few weeks. He'd spoken to the laundromat owners today.
"They're not happy about it and it's certainly something that they don't expect to occur."
Fortunately, nobody was in the Sandringham building when the fire broke out.
Six Fire Service appliances were sent to the Sandringham fire at about 2.38am.
"The fire was located at the rear of the laundromat on the ground floor," said Jaron Phillips, Northern Fire Communications shift manager.
"A search of the upper floors was carried out. Everyone was accounted for."
Just a few hours later, a fire at a two-storey building in Waimate, Canterbury, killed three people - a father, his wife, and their child.