Neighbours say they reported a strong gas smell two weeks ago and that they had been feeling dizzy.
A child has been killed and three other people are in hospital with life-threatening injuries after a gas blast destroyed a house in south London.
The blast, which happened on Galpin’s Road in Thornton Heath at about 07:00 BST, also damaged other properties.
Residents say they had reported a strong gas smell two weeks ago and had felt dizzy in recent days.
Merton Council described the explosion as a “major incident” and said it was working with emergency services.
Four people were treated on Galpin’s Road. One person was discharged at the scene.
In a statement, the fire service said: “Sadly, a child was also pronounced dead at the scene. All LAS (London Ambulance Service) crews have now been stood down.”
Two neighbours, Kutoya Kukanda, 50, and Delroy Simms, 62, said they helped rescue three children from the rubble.
They added that the house next door had been badly damaged by the blast.
About 40 properties have been evacuated as a precaution. A 50m cordon is in place.
People who were evacuated from Galpin’s Road in their pyjamas after the blast, at about 07:10 BST, said their windows were shattered in the explosion.
In a statement Merton Council said: “Firefighters are currently carrying out systematic searches and working to make the scene safe.
“An evacuation centre has been established at the New Horizons Centre.”
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