Four fire engines and around 25 firefighters were called to a bakery industrial unit fire on Silverdale Road in Hayes.
A bakery oven was completely destroyed by the blaze. Staff evacuated the building before the Brigade arrived.
The Brigade was called at 1151 and the fire was under control by 1324. Fire crews from Hayes, Hillingdon, Heathrow and Feltham fire stations were in attendance.
The cause of the fire is under investigation.