Ten fire engines and around 70 firefighters tackled a flat fire on Rowan Road in West Drayton.
Half of the ground, first and second floors of the residential block were damaged by fire. Part of the roof was also damaged by the blaze. There were no reports of any injuries.
Firefighters removed one gas cylinder and cooled it to an ambient temperature as some cylinders can explode when exposed to heat.
Station Commander Andy McKay, who was at the scene, said: "Crews worked swiftly in hot, challenging conditions to bring the fire under control.
"Traffic was building up, so we urged people to avoid the local area where possible.
"The fire was producing a significant amount of smoke, which has now subsided."
The Brigade's 999 Control Officers took 11 calls to the blaze and used 999Eye to to live stream the blaze from a smart phone to screens in the Control Room, allowing for greater visibility of the incident.
When a 999 call is received by the Brigade, the caller may be asked if they would like to provide a live video stream of the scene using their smartphone. The Control Officer will send a text message with a secure, one-time-use link that opens a live stream direct from the phone to the Control Room. 999Eye provides better situational awareness and allows us to offer the best advice based on live footage.
The Brigade was called at 1657 and the fire was under control by 1853. Fire crews from Heathrow, Southall, Feltham, Hillingdon and surrounding fire stations attended the scene.
The cause of the fire is under investigation.