A 27-year-old woman rescued from a smoke-filled house in Co Antrim is lucky to be alive, the fire service said.
Firefighters were called to the property in Leyland Heights, Ballycastle, at about 11pm on Monday night.
Jim Murphy, Northern Ireland Fire and Rescue Service Group Commander, said crews using specialist equipment detected fatally high levels of carbon monoxide.
Mr Murphy said: "This young lady lay down in a room for possibly up to two hours, breathing in carbon monoxide. She's very, very fortunate to be alive. Had she been left for much longer I think easily she could have died."
It is understood that a plastic bag had been thrown on to a fire and had opened halfway up the chimney, causing it to block.
Mr Murphy said: "The only thing that should be put on a fire is fuel. This bag shot up the chimney and was blocking fumes. You do not always get a strong smoky smell."
The woman was given oxygen at the scene before being taken to hospital by ambulance.
Mr Murphy has urged householders to install carbon monoxide detectors.