A 66-year-old woman has died, and her husband, 73, and daughter, 28, are in critical condition after a carbon monoxide poisoning incident in Forni di Sopra, Udine, Italy.

The alarm was raised at 4:30 AM when the daughter’s partner, located in Tuscany, received alarming messages about her symptoms of vomiting and loss of consciousness.

Emergency responders instructed the daughter to leave the house, while neighbors rescued her unconscious parents.

Despite rapid medical intervention, the woman was pronounced dead at the scene.

Her husband was airlifted to a hospital for hyperbaric oxygen therapy, and the daughter was hospitalized locally.

Investigators suspect the home’s heating system as the source of the deadly gas.