A Wisconsin family survived a carbon monoxide leak in their home, not because of a detector, but because of their cat.
It was the middle of the night when their cat 'Gracie' suddenly started pounding on the door.
"We have three cats and all three of them do run the house. We're just here to feed them and take care of them," Reedsburg resident Kevin Shanahan told CBS.
Mr Shanahan and his wife would likely have died if not for the quick thinking of their kitty.
Carbon monoxide was seeping throughout the home at about 1am - and a piece of equipment that would normally detect the odourless gas wasn't working properly.
"All of a sudden Gracie, she's pounding, knocking, knocking, knocking at the door. Gracie started pounding at the door, and pounding hard," he said.
"So I got out of bed to stop her from pounding at the door, and I looked to my left and [my wife] Annette was in the chair.
Ms Shanahan said she was clinging on to the arm of the chair and thought she was about to die.
"She called 911 and all she could say was 'can't breathe'," he said.
When firefighters arrived they discovered lethal levels of carbon monoxide in the home, caused by a malfunction in the hot water heater.
The Shanahans were taken to the hospital, where they spent the night. The couple said they'd rather not think about what would have happened had it not been for Grace.
"[We're] very lucky. If it wasn't for the cat, I don't know how much she [knew she] was saving our lives, but she wanted to get out of there and she knew enough to know something was wrong," Mr Shanahan said.
The pair had a carbon monoxide detector, which is standard in the United States. The device was 15 years old, and manufacturers recommend they be replaced every five years.
The family says they'll always have a new appreciation for an old saying - that they were saved by Grace.
"I say saved by Grace, but saved by the grace of God, because she doesn't usually sleep with us," said Mr Shanahan.