Ten fire engines and around 70 firefighters were called to a fire under the railway arches on Silwood Street in Bermondsey.
A gas cylinder was alight. There were no reports of any injuries.
Station Commander Tony Perks, who was at the scene, said: “Crews worked hard to bring the fire under control as quickly as possible and prevented the fire from spreading.
“Due to the ongoing emergency services presence at the scene, we’re urging people to avoid the area this evening where possible to help minimise disruption.”
The Brigade's Control Officers took the first of four calls to the fire at 2006 and sent crews from New Cross, Deptford, Old Kent Road, Dockhead and surrounding fire stations to the scene. The fire was under control by 2113.
The cause of the fire is under investigation.