A woman in her 70s has died and a man, 75, taken to hospital after a suspected carbon monoxide leak at their home.
Police, fire crews and paramedics were called to Old Penkridge Road in Cannock, Staffordshire, at about 10:30 BST after reports of a sudden death.
The pair were found unresponsive inside the house and the man was taken to hospital in a serious condition.
Staffordshire Police said officers believed they had suffered carbon monoxide poisoning.
The death is being treated as unexplained and not believed to be suspicious, the spokesman added.
West Midlands Ambulance Service said: "When ambulance crews arrived they found two patients, a man and a woman, who had been removed from the property by the fire service after they were found unresponsive inside.
"Sadly, the woman was confirmed dead by ambulance staff at the scene."
The man was given oxygen by firefighters and emergency treatment at the scene. He was then taken to New Cross Hospital in Wolverhampton.