Four fire engines and around 25 firefighters were called to a fire at a composting facility on Newyears Green Lane in Uxbridge.
Around 200 square metres of composting manure was alight and most of an industrial conveyor, used to transport bulk materials, was damaged by fire. There were no reports of any injuries.
The Brigade was called at 0108 and the fire was under control by 0334. Fire crews from Ruislip, Northolt and Hillingdon fire stations attended the scene.
The Brigade's Fire Investigators believe the fire was accidental and involved a piece of machinery.