Six fire engines and around 40 firefighters tackled a fire at a derelict building on Queensbury Road in Wembley.
A single-storey derelict structure was destroyed by fire. There were no reports of any injuries.
Firefighters removed and cooled two gas cylinders to an ambient temperature as a precaution, as some cylinders can explode when exposed to heat.
The Brigade's 999 Control Officers received a call to this incident at 2020 and mobilised crews from Wembley, Acton, Ealing and surrounding fire stations to the scene. The fire was under control by 0043.
The cause of the fire is believed to be accidental and is under investigation.