The blaze at a London apartment block that killed dozens of people started in a Hotpoint fridge freezer, announced police, while not ruling out manslaughter charges.
The cladding on Grenfell Tower failed all safety tests, added the police.
At least 79 people died in the fire.
Police Detective Superintendent Fiona McCormack said the Hotpoint model, FF175BP, was not subject to recall and that the manufacturer was doing further tests.
“We now have expert evidence that the fire was not started deliberately,” McCormack said.
Whirlpool Corp, the world’s largest maker of home appliances, owns the Hotpoint brand in the Europe and Asia Pacific regions. In the United States, the brand now belongs to Haier, following the Chinese group’s purchase of General Electric Co’s appliance business.
“We are working with the authorities to obtain access to the appliance so that we can assist with the ongoing investigations,” Whirpool said in a statement. “Words cannot express our sorrow at this terrible tragedy.”
Police said both the insulation and tiles used in cladding at the 24-storey Grenfell Tower block failed all post-fire safety tests.
“Preliminary tests show the insulation samples collected from Grenfell tower combusted soon after the test started,” McCormack said.
Such were their concerns after the tests that the information was immediately shared with government to disseminate more widely.
“Given the deaths of so many people we are considering manslaughter as well as criminal offenses and breaches of legislation and regulations,” McCormack said.
The blaze, Britain’s worst since World War Two, has heaped pressure on Prime Minister Theresa May, already fighting for her political survival after her party lost its parliamentary majority in a snap election on June 8.
When speaking about the 79 people dead, presumed dead or missing, McCormack said: “I fear that there are more.”
She repeated calls for anyone with information on who might have been in the tower to come forward. The call comes after London Mayor Sadiq Khan’s pledge to seek an amnesty for people who may have been living in the tower illegally.
McCormack said: “What we haven’t got is a picture of how many people might have been in there. That’s the number I’m really worried about.”
She added that authorities are “looking at every health and safety and fire safety offense and we are reviewing every company at the moment involved in the building and refurbishment of Grenfell Tower.”
Eleven buildings have now been identified as having combustible cladding such as that used on the Grenfell Tower. The cladding is being studied amid fears that the panels fueled the fire in the 24-story building that was engulfed in less than an hour.
Buildings in London, Manchester and Plymouth are among those where problem cladding has been identified.
Fears about cladding is not limited to apartment buildings, and at least one hotel chain is calling in experts to make certain it meets safety regulations. Premier Inn said Friday it had “concerns” about the material on some of its buildings, though it is different to the type used on Grenfell.