Three people are fighting for their lives after a car was left running in a garage and filled a St. Mary’s County, Maryland, residence with carbon monoxide Saturday night.

Bay District firefighters arrived at Planters Court in Lexington Park just after 7:30 a.m. to help an unconscious person inside a house.

They found three people going in and out of consciousness with carbon monoxide poisoning.

Officials said someone forgot to turn off the car and carbon monoxide leaked into the house. No one was in the car.

A Maryland State Police helicopter flew them to the hospital.

Crews also rescued a dog from the house, who is now doing fine.