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, has urged anyone who thinks they may own one of the appliances of the model FF175BP or FF175BG to call 0800 316 3826.
It 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.
During the incident, heroic residents of the Grenfell tower saved their neighbours by banging on their doors and guiding them to safety, it has emerged.
Local community centres and religious buildings have opened to help those who have lost their homes, and left with nothing but their pyjamas.
Some put their own lives at risk to rescue others.
Muslims awake due to Ramadan may have saved lives
Rashida, a local resident, told Sky News how Muslims observing Ramadan may have saved lives in the tower block, as many of them were awake.
She said: “Most Muslims now observing Ramadan will normally not go to bed until about 2am, maybe 2.30am, [when] they have their late night last meal. They do their last prayer.
“So most of the families around here would have been awake and I think even with the noise of the helicopters, it would have brought a lot of attention to a lot of residents, non-Muslim as well, [who] would have thought ‘something’s going on that’s not quite normal.'”
She spoke of how tight-knit the community was, and how many different nationalities lived in the tower.
She said: “It’s a very diverse area, we have all nationalities, all religions. We all live peacefully amongst each other, there is not much crime – [not] higher than anywhere else. You can walk around safely late at night… we all know each other. There is a very high population of Moroccans, and for some reason we all live close to each other. Everyone knows each other.”
Nadia Yousuf, 29, told BuzzFeed Muslim residents were among the first to notice the fire, as they woke up to prepare to break their fast.
“They saw it just after they woke up to eat”, she said.