Six fire engines and around 40 firefighters attended a fire at a recycling site on Newyears Green Lane in Harefield.
Around 40 tonnes of waste was alight. There were no reports of any injuries.
The Brigade's Control Officers received around seven calls about the fire.
The first call was received at 1900 and Control Officers mobilised crews from Hillingdon, Ruislip and surrounding fire stations to the scene. The fire was brought under control by 2018.
The cause of the fire has been recorded as undetermined.