Insulation on the building also failed tests and the Metropolitan Police will consider manslaughter charges.
Seventy-nine people are feared dead after the blaze destroyed 151 homes in the Kensington tower block.
The government has ordered immediate testing of the Hotpoint fridge freezer which was involved.
Whirlpool, who owns Hotpoint, said: "We offer our most profound condolences to the victims, those who have lost loved ones, homes, and possessions, and to their friends and families."
It said it was working with the authorities to obtain access to the appliance so that it could assist with the ongoing investigations.