Eight fire engines and around 60 firefighters are dealing with a fire at a recycling plant on Neasden Lane in Neasden.
A large stack of mixed recyclables are alight.
The fire services was called at around 2am on Sunday morning.
Fire crews from Willesden, Park Royal, Wembley, Paddington, Northolt and West Hampstead fire stations are at the scene.
The cause of the fire is not known at this stage.
Residents are being advised to keep their windows and doors closed
A road closure to all vehicles has been put in place between on the B453 Neasden Lane in both directions between Church Road and Prout Grove