The Grenfell Tower fire was started by a Hotpoint fridge-freezer before spreading to the building's "combustible" cladding, investigators have said.
Detective Superintendent Fiona McCormack from the Metropolitan Police, said the Hotpoint FF175BP model had not been subject to any product recall.
Witnesses at the scene of the 24-storey fire on 14 June said a resident told neighbours his fridge had "exploded" while alerting them to the initial blaze.
Det Supt McCormack said tests had been carried out on cladding installed on the outside of Grenfell Tower last year to improve insulation and the building's appearance.
She said the tests carried out as part of the investigation so far were “small scale”, but added: “All I can say at the moment is they (tiles and insulation) don't pass any safety tests.
“What we are being told at the moment by the Building Research Establishment is that the cladding and insulation failed all safety tests.”
She added: “Our investigation is to establish how the fire started.”
Police are looking at "every criminal offence from manslaughter onwards", as well as health and safety regulations and investigating all companies involved in the building and refurbishment of Grenfell Tower.
Det Supt McCormack said the number of victims confirmed or presumed dead in the fire still stands at 79 but said efforts to confirm who was inside the building at the time continued.
She urged people to come forward with information about any missing friends and relatives, assuring them that the tragedy would not be used by the Home Office or police to check immigration status.
"I know that there is a fear the [death toll] is a lot higher and I do not want any hidden victims of this tragedy," she added.