A Fort Washington family was hospitalized Monday after being exposed to high levels of carbon monoxide in their home.

About 11 p.m., police received a report that a woman in a home in the 12400 block of Surrey Circle Drive was semi-conscious.

The 911 responder who took the call determined that the family, which had lost power over the weekend because of Hurricane Irene, had been using a gas generator to power some appliances. The generator was in the single-family home’s attached garage with the door closed.

Fort Washington firefighters, paramedics and hazmat personnel responded to the home, where they found the woman unconscious on a bed and dangerously high carbon monoxide levels of more than 900 parts per million (ppm). Prince George’s County Fire/EMS officials noted that a normal carbon monoxide level would fall between 0 and 30 ppm.

The unconscious woman was taken by medevac to a hospital in Baltimore for treatment and the other three people in the house — a woman and two men — were treated at area hospitals.

“With the high level of [carbon monoxide] detected in this house it was only a matter of minutes before fatal injuries would have occurred,” an EMS supervisor said.

The victims are expected to recover fully, and the house has been ventilated.

Officials advise that people should never use a gas-powered generator indoors.

Click here for more on using generators and other tips on dealing with power outages and natural disaster.