Around 40 firefighters attended a fire on Anchor Close in Barking this morning.
The London Fire Brigade was called at around 8.30am on May 20.
Six engines have been deployed to the scene, where part of a four-roomed flat on the second floor of a residential block was alight.
Half of the building's roof and loft space was also on fire.
One woman left the building before the Brigade arrived and was treated on scene by London Ambulance Service (LAS) crews after suffering from smoke inhalation.
Station Commander Gary Wilson, who was at the scene, reports that "smoke in the area has now subsided.
He added: "One of the Brigade's new 64-metre turntable ladders was used to get water on to the roof of the building externally.
"It was also used as an observation tower, providing crews with an aerial view of the incident to help identify remaining hot spots."
The Brigade's 999 Control Officers took 10 calls to the blaze.
The fire was under control by 10am.
Fire crews from Barking, Plaistow, East Ham, Ilford and Wennington fire stations are at the scene.
The cause of the fire is under investigation.
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