Four fire engines and 21 firefighters and officers were called to a van alight in Peckham Grove, Peckham.
A transit van was destroyed in the fire, another vehicle was damaged and the front of a nearby building was slightly damaged.
Firefighters removed a propane gas cylinder and cooled it to an ambient temperature.
Around five people were evacuated from a block of flats adjacent to the van.
The Brigade was called at 1029 and the fire was under control at 1140. Fire crews from Peckham, Old Kent Road, Brixton and Lambeth attended the scene.
The cause of the fire is believed to be accidental.