A garden shed next to a church on Uxbridge Road in Hanwell was destroyed by fire on Friday evening.
Firefighters set up a 25 metre safety cordon after reports that propane gas cylinders were stored in the shed.
11 cylinders were found, cooled and made safe. No one was injured.
Four fire engines, 21 firefighters and officers from Twickenham, Heston and Southall fire stations attended the incident.
The Brigade was called at 1742 and the fire was under control at 2010.
The cause of the fire is under investigation.