Six fire engines and around 40 firefighters were called to a fire at a shop with flats above on Uxbridge Road in Hanwell.
Part of the ground floor shop and part of a first floor flat were damaged by fire. Two men were treated on scene by London Ambulance Service crews and one of them was taken to hospital.
The Brigade’s 999 Control Officers took 10 calls to the blaze.
Station Commander Dean Wilkinson, who was at the scene, said: “Crews worked incredibly hard to quickly bring the fire under control.
“Roads were closed and buses were diverted whilst firefighters made the scene safe.
“This is a timely reminder to test your smoke alarms. There were no working smoke alarms fitted inside the property.
“Having working smoke alarms is so important in helping to detect fires and save lives. They can provide time to escape.
“As a minimum you should have smoke alarms on every floor - in the hallways and the rooms you use the most, plus a heat alarm in the kitchen.”
The Brigade was called at 1939 and the fire was under control by 2023. Fire crews from Southall, Acton, Ealing and Heston fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.