Roads around Sussex Gardens in Paddington were closed after a gas cylinder explosion on a building site.
Emergency services were called to the incident just before 1.30pm.
It is not thought there were any casualties.
London Fire Brigade said an acetylene cylinder was alight and firefighters worked to cool it and make it safe.
A 200-metre exclusion zone around the cylinder was in place affecting a number of roads in the area including Westbourne Terrace and Spring Street.
The incident, which was under control just before 6pm, took place on a construction site during utilities work related to the Crossrail programme.
A spokesman for Thames Water, which manages the site, said: "We’re very sorry to anyone inconvenienced by the disruption around Sussex Gardens today.
"Our teams were working on a project to strengthen water pipes when a small fire, caused by a gas canister, broke out. We’ll carry out a full investigation into what happened.”
A4209 Sussex Gardens junc of Spring St- there's various road closures in place due to a fire. Expect delays.
— TfL Traffic News (@TfLTrafficNews) July 2, 2015
Something bad happened in Sussex gardens london,could be a crossrail@problem,hope everyone's ok
— rodney buckingham (@roddersbuck) July 2, 2015
@roddersbuck a gas cylinder has exploded on a construction site in #SussexGardens. Road closures currently in place.
— Westminster MPS (@MPSWestminster) July 2, 2015
Live news Sussex Gardens London gas leak traffic redirect at Paddington and Praed st pic.twitter.com/EYwYXr7dA5
— Joanne BeatArtist (@JBeatartist) July 2, 2015
Gas explosion. Locked out of my home until I dont know when.. #FML #sussexgardens #explosion pic.twitter.com/zGKlPGkuOO
— Live Young Abroad (@Hannah_Beraud) July 2, 2015
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