Carbon Monoxide

What is carbon monoxide?

Carbon monoxide, or CO, is a poisonous gas that cannot be seen or smelled and can kill a person in minutes. Carbon monoxide can quickly build up to unsafe levels in enclosed or semi-enclosed areas.

What are some common sources of carbon monoxide?

Carbon monoxide is produced by incomplete combustion from cars and trucks, small gasoline power equipment like weed trimmers and chain saws, boat engines, gas and camp stoves, lanterns, burning charcoal and wood, and gas ranges, ovens, or furnaces. Tobacco smoke is a significant source of carbon monoxide in homes with smokers.

What are the symptoms of carbon monoxide poisoning?

Common initial symptoms are headache, dizziness, fatigue, weakness, confusion, and nausea. Low-level carbon monoxide poisoning can be difficult to diagnose because the symptoms are like other illnesses, such as the flu. The following could be a sign of carbon monoxide poisoning:

• Symptoms go away when you leave your home and come back when you return.
• Everyone in the home has similar symptoms at the same time.

Breathing in high levels of carbon monoxide can cause loss of consciousness and death. People who are sleeping can die from carbon monoxide poisoning before ever knowing they are being exposed to the gas.

Who is at risk from carbon monoxide poisoning?

All people and animals are at risk for carbon monoxide poisoning. Certain groups, such as unborn babies, infants, and people with chronic heart disease, anemia, or respiratory problems, are more easily affected by carbon monoxide poisoning.

What should be done if you suspect someone has carbon monoxide poisoning?

• Immediately go outside to get fresh air. Call 911.
• If someone is unconscious and cannot leave, open windows and doors to bring in fresh air. Turn off the source of carbon monoxide. Go outside for fresh air. Call 911.
• After calling 911, do a head count to check that all people are accounted for. Don't reenter the building until emergency responders have given you permission. You could lose consciousness and die if you go back in without knowing if it's safe.
• If the source of the carbon monoxide is a malfunctioning appliance, don't use that appliance until it has been fixed by a trained professional.

Should I install a carbon monoxide alarm?

Yes, these detectors are similar to smoke alarms and can warn you when carbon monoxide levels become unsafe. If the alarm goes off, evacuate the building and call 911. Follow the carbon monoxide detector instructions for routine maintenance, including regular replacement of batteries. If the carbon monoxide detector is wired to the electrical supply, make sure it has back-up batteries for when the electricity is off.

Washington State law (RCW 19.27.530) requires carbon monoxide alarms to be installed in new residences. As of January 1, 2013, carbon monoxide alarms are required in existing apartments, condominiums, hotels, motels, and single-family residences, with some exceptions. Owner-occupied single-family residences, legally occupied before July 26, 2009, are not required to have carbon monoxide alarms until they are sold. For more information on the carbon monoxide alarm requirements, contact your local building code official or see the State Building Code Council's Carbon Monoxide Alarm page.

Motor homes and boats should also have carbon monoxide alarms.

How do I prevent carbon monoxide poisoning during a power outage?

• Never use a generator inside your home, garage, carport, basement, or near an outside window, door, or vent.
• Never use a charcoal or gas grill in an enclosed space, such as inside your home, garage, or in a tent or camper.
• Don't burn charcoal in your fireplace. A charcoal fire will not create a chimney draft strong enough to push the carbon monoxide to the outside.
• Never use a gas range or gas oven to heat your home.
• Never sleep in a room while using an unvented gas or kerosene heater.
• See our fact sheet, which is available in multiple languages, on preventing carbon monoxide poisoning during a power outage.

Generator Safety

Gas powered generators should be at least 20 feet away from buildings. Even at 20 feet away, air flow patterns could still blow carbon monoxide into homes through attic vents, windows, or doors, so it's very important to have a working carbon monoxide detector inside the home. There are now models of generators with features to help reduce the risk of the CO poisoning. Look for generators with technology that reduce CO exhaust emissions or have an automatic shutoff when it senses certain concentrations of CO around the generator. Get tips on using a generator during a power outage.

How can I prevent carbon monoxide poisoning from vehicles and other equipment?

• Never run a vehicle, lawn mower, generator, snow blower, or other fuel-burning engine in a garage, even when the garage door is open.
• Have a mechanic check the exhaust system of your car every year. A small leak in your car's exhaust system can lead to a build up of carbon monoxide inside the car.
• Don't allow people to travel inside truck canopies and campers. Vehicle exhaust can be drawn into the covered or enclosed area of canopies and campers.
• Boaters should be aware of exhaust "back drafting" into the boat's cabin, cockpit, or deck. Make sure people swim and play away from the engine exhaust of the boat. Don't “teak surf” or hang onto and ride on the swim platform on the back of boats.
• Never use gasoline powered equipment indoors or in poorly ventilated areas.

How can I prevent carbon monoxide poisoning from my home appliances?

• Have oil and gas appliances and fireplaces, as well as wood stoves, checked every year by a trained professional.
• Make sure chimneys and flues are routinely checked and cleaned. Never burn anything in a stove or fireplace that isn't vented.
• For open fireplaces, don't let them burn or smolder overnight. Without enough heat in the fireplace, a downdraft can push smoke and carbon monoxide into the home.
• Don't use unvented fueled heaters.
• If you suspect a gas leak, leave your home immediately, call 911, and contact your gas company. Don't go back into the home until the problem has been resolved.

More Resources

Carbon Monoxide Poisoning, CDC - Educational materials in various formats and languages, prevention and clinical guidance, and research studies.

Carbon Monoxide Data, Washington Tracking Network - Search exposure indicators to see how many people are affected by carbon monoxide exposure over a period of time.

Power Outage: Emergency Preparedness - Carbon monoxide, food, and drinking water power outage fact sheets.

Carbon Monoxide Alarm Laws, State Building Code Council - January 1, 2013 residential carbon monoxide alarm requirements and other related codes.