Around 40 firefighters in six fire engines attended a suspected gas explosion on Western Road in Southall.
Three people, two men and a woman were taken to hospital following the explosion.
The first floor and roof of a two-storey building with a shop and flats above has suffered significant structural damage as a result of the building partially collapsing.
Part of the first floor and roof was damaged by a fire which occurred following the explosion.
There were no reports of any other injuries. Neighbouring properties were evacuated as a precaution and road closures are in place.
Station Commander Simon Horn, who was at the scene, said: “Crews were joined by our Urban Search and Rescue team using specialist equipment to carry out a systematic search of the property. They were able to confirm that everyone has been accounted for.
“Initial crews worked quickly in a challenging situation to extinguish the fire. However, a cordon of around 50 metres will remain in place and people are asked to avoid the area.”
The Brigade was called at 1:29pm and the incident was under control by 4:05pm. The cause of the incident is under investigation.
