A child has died following a "hazardous materials incident" in east London.
Fire crews attended a property in Barking Road, Upton Park, Newham, after two adults and two children went to hospital complaining about a smell of chemicals in a flat.
One of the children later died in hospital, the London Fire Brigade (LFB) said.
The Metropolitan Police is investigating Tuesday's incident, "supported by the brigade", LFB said.
Around 12 people were evacuated from surrounding properties as a precaution while crews responded.
Specially trained firefighters carried out a "systematic sweep" of the affected property, working to detect any hazardous materials present and ventilate the scene, LFB said.
In a statement, it said: "The first call reporting the incident was received at 1.18pm, and firefighters from Poplar, Millwall, Euston and surrounding fire stations attended the scene. The incident was over for crews by 4.23pm."
Newham Council said it had opened a local rest centre for those forced to leave their homes as residents were not currently allowed to return.
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A council spokesperson said: "First of all, our thoughts are with the family of the young child who has so tragically lost their life in this terrible incident.
"Details about the exact nature of the incident are not yet clear and the Metropolitan Police will remain on the scene as the investigation progresses.
"As a council we have taken speedy measures to ensure those residents who were evacuated are being cared for in a warm, safe environment."
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