Fifteen fire engines and around 100 firefighters dealt with a fire on an industrial estate on Abbey Road in Park Royal.
Part of the ground floor and half of the first floor and the roof of a single-storey industrial unit was damaged by fire. There were no reports of any injuries.
The Brigade was called at 0919 and the fire was under control by 1332. Fire crews from Park Royal and surrounding fire stations were at the scene.
The fire is believed to have been accidental but the exact cause has been recorded as undetermined.