Three people were taken to hospital with suspected carbon monoxide poisoning on Friday.
An Epsom fireman said the crew was called to Millais Crescent, in Ewell, to reports that someone was suffering from inhalation of the potentially lethal gas which is colourless, odourless and tasteless.
He said a woman and an 18-year-old were involved in the incident.
A South East Coast Ambulance Service spokesman added: "We attended with one ambulance crew.
"Three patients were taken to Epsom Hospital for checks."
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