Two elderly people were taken to hospital after carbon monoxide leaked into their home in Cornwall.
A neighbour alerted the fire service after finding the couple unconscious at their home in Rope Walk, Mount Hawke, on Thursday evening.
Firefighters wearing breathing apparatus removed the two elderly occupants from the house. They were treated by paramedics at the scene and then taken to the Royal Cornwall Hospital in Treliske, Truro.
Cornwall Fire and Rescue Service said a blocked flue in the solid fuel heating system had caused a build-up of the gas.
It followed an incident in Bodmin in which a man in his 50s had a lucky escape when a carbon monoxide alarm alerted emergency services to a dangerous amount of the poisonous gas in his home.
Fire crews from Bodmin were called to the aid of the man after his Lifeline alarm detected traces of the gas at his property in St George's Crescent.
The alarm was linked to the Lifeline system, which is permanently monitored, and staff then alerted the fire and rescue service. The man was suffering from breathing difficulties and was treated by paramedics.
"The man had a very lucky escape," said group manager Mark Blatchford of Cornwall Fire and Rescue Service.
"The Lifeline system really did provide a life line. Had the alarm not been in place, the man could have been very seriously ill."
