Four fire engines and around 25 firefighters were called to a fire at a trading estate on Trumpers Way in Hanwell.
A small part of a single-storey unit and a mezzanine floor were damaged by fire. There were no reports of any injuries.
A London Fire Brigade spokesperson said: “The alarm was raised when a member of staff heard an alarm sounding and saw smoke coming come from the roof of the building. They then called the Brigade."
“Crews worked incredibly hard and successfully stopped the fire from spreading to a number of other neighbouring properties.”
The Brigade was called at 0344 and the fire was under control by 0451. Fire crews from Ealing, Southall and Acton fire stations attended the scene.
The Brigade’s Fire Investigators believe the fire was accidental and involved a mobile dust extractor.