Ten fire engines and 72 firefighters and officers were called to a fire at a single storey car workshop on The Green in Southall.
The whole of the workshop was destroyed by the blaze. Two people from the workshop were taken to hospital by London Ambulance Service crews.
Gas cylinders were reported inside the building. As some cylinders can explode when exposed to heat a hazard zone was set up and a number of people evacuated as a precaution.
The Brigade was called at 2114 and the fire was under control by 2357. The cause of the fire is not known at this stage.