What is carbon monoxide poisoning?

Carbon monoxide poisoning is a life-threatening emergency. It occurs from breathing in (inhaling) carbon monoxide (CO) fumes.

What causes carbon monoxide poisoning?

CO is a colorless, odorless, tasteless gas made when fuel burns. Fuels include wood, gasoline, coal, natural gas, or kerosene. Breathing in CO fumes prevents the body from using oxygen correctly. This can harm the brain, heart, and other organs. People with health problems, such as heart and lung disease, are at greater risk for harm. Infants, children, pregnant people, and older adults are also at greater risk.

Most CO exposures happen in the winter in cold climates. The very common source of CO poisoning is unvented space heaters in the home. An unvented space heater uses combustible fuel and indoor air for the heating process. It vents the gases it makes into the room, instead of outdoors. A space heater that is not installed right or not working correctly can release CO and other toxic fumes into the room and use up much of the oxygen in the room.

Some space heaters use kerosene or natural gas for fuel. Newer models have oxygen sensors that shut off the heater when the oxygen level in the room falls below a certain level. Older models don't have this safety feature. Because of these safety problems, some states ban unvented space heaters.

Other common sources of CO are:

• Fires

• Malfunctioning cooking appliances

• Tobacco smoke

• Clogged chimney

• Auto exhaust or idling vehicles

• Malfunctioning water heater

• Malfunctioning oil, wood, gas, or coal furnaces

• Malfunctioning gas clothes dryer

• Wood burning fireplace or gas log burner

• Gas or fuel-burning appliances in cabins or campers, barbecue grills, pool or spa heaters, or ceiling-mounted heating units

• Generators that run on gasoline

• Open air exposure to motorboat exhaust

What are the symptoms of carbon monoxide poisoning?

These are the most common symptoms of CO poisoning:

• Headache

• Dizziness

• Weakness

• Nausea and vomiting

• Rapid heartbeat

• Shortness of breath

• Seizures

• Chest pain

• Cardiac arrest

• Loss of hearing

• Blurry vision

• Disorientation

• Loss of consciousness or coma

• Respiratory failure

• Death

These symptoms look like other health problems, such as the flu or food poisoning. Always see your healthcare provider for a diagnosis.

How is carbon monoxide poisoning diagnosed?

Your healthcare provider often diagnoses CO poisoning based on known exposure. Treatment must be started right away.  You may also have a blood test to check for CO in your blood. A physical exam may also show changes in mental status. You may also have chest X-ray, heart, and neurological tests.

How is carbon monoxide poisoning treated?

If your child or other family members have any symptoms of CO poisoning, stay calm but act quickly:

• Leave the area and get fresh air right away. Turn off the CO source, but only if you can do so quickly and safely without endangering yourself or others.

• Call 911 or your local emergency medical service (EMS).

• If someone has stopped breathing, get the person to fresh air right away. Start CPR and don't stop until they are breathing on their own, or someone else can take over. If you can, have someone call 911 right away. If you are alone, do CPR for 2 minutes and then call 911.

Your healthcare provider will determine further treatment for CO exposure. Emergency care may include oxygen therapy. In serious cases, hyperbaric oxygen may be used.  

What are possible complications of carbon monoxide poisoning?

CO poisoning is life-threatening. It can cause death. Brain damage can also result if the brain is without oxygen for too long.

Can carbon monoxide poisoning be prevented?

These important steps can help protect against CO poisoning:

• Have your furnace and fireplace cleaned and checked before each heating season.

• Only use fuel-burning space heaters in well-ventilated areas. Electrical space heaters pose no danger of carbon monoxide poisoning, unlike those that burn fuels, such as kerosene.

• Don't start or leave cars, trucks, or other vehicles running in an enclosed area, such as a garage, even with the outside door open.

• Don't use portable heaters or lanterns while sleeping in enclosed areas, such as tents, campers, and other vehicles. This is even more important at high altitudes, where the risk of CO poisoning is increased.

• Never use a gas stove or oven for heating a room.

• When using a gas-powered generator for electricity, be sure to keep it a safe distance away from the home.

• Install battery backup CO detectors in your home to warn you if CO levels begin to rise. 

Get medical care right away if you think you or a member of your family has CO poisoning.

Key points about carbon monoxide poisoning

• CO poisoning occurs when you breathe in CO fumes. The CO prevents the body from using oxygen correctly.

• Most CO exposures happen in the winter. A common source is unvented space heaters.

• Symptoms of CO poisoning include headache, dizziness, weakness, nausea and vomiting, rapid heartbeat, shortness of breath, seizures, chest pain, disorientation, and loss of consciousness.

• CO poisoning needs to be treated right away by getting outside to fresh air and calling 911.

• Prevention of CO poisoning includes using battery backup CO detectors and assuring that your fireplace and heaters are working correctly.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.