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Carbon Monoxide Poisoning

What is carbon monoxide poisoning?

Carbon monoxide poisoning is an illness caused by breathing too much carbon monoxide. Carbon monoxide (CO) is a colorless, odorless gas. When there is too much CO in the air you are breathing, your body does not get enough oxygen. You may become unconscious. You could die or, if you survive, your brain may be permanently damaged.


In the US about 500 people die accidentally every year from CO poisoning. Infants, older adults, and people with anemia or heart or lung disease are particularly sensitive to high levels of CO.

How does it occur?

CO is released into the air by burning fuels such as natural gas, gasoline, oil, kerosene, wood, or charcoal. If a gas appliance, such as a stove, furnace, water heater, or generator, is not working right or is not used correctly, a dangerous level of CO may build up in the air. The level of CO may also get too high if fuel is being burned in an area that is not well ventilated. For example, levels of CO may build up in a house when a gas or kerosene heater is used in an attached garage and the garage door is closed. The buildup of CO in the house can happen even if the door between the house and garage is closed. Levels of carbon monoxide can build up to dangerous levels in seconds.


Dangerous levels of CO can also be a risk when you ride in the back of a pickup truck with a camper shell or if you swim behind a running boat or tie up your boat next to a boat with the engine running.

What are the symptoms?

Many of the symptoms of CO poisoning are like the symptoms of mild stomach flu or food poisoning. Symptoms include:

  • headache
  • nausea
  • blurry or double vision
  • feeling like you cannot get enough air
  • dizziness
  • confusion
  • fainting.

Because you cannot see or smell CO, you may not know that carbon monoxide poisoning is causing your symptoms. One way to check this is to leave your house and see if your symptoms get better. If they come back when you return home, you should suspect CO poisoning. Also suspect carbon monoxide if others in your household have similar symptoms, especially if everyone's symptoms started at about the same time.


If you are exposed to high levels of CO for too long, you could die.


If you are sleeping when the CO levels become too high, you may not wake up before the CO kills you. This is why it is so important to use proper heating and ventilation in your home.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and examine you. You will have a blood test for carbon monoxide poisoning.

How is it treated?

If you have symptoms that you think could be caused by CO poisoning:

  1. Get fresh air right away. Get everyone out of the building.
  2. Call 911 or have someone take you to an emergency room and tell them you think you might have CO poisoning. CO poisoning can be diagnosed with a blood test if the test is done soon after exposure to CO.

You will be given oxygen to treat carbon monoxide poisoning.

How can I help care for myself?

If you have been treated for CO poisoning:

  • Get plenty of fresh air afterwards.
  • If you were in your home when you became ill, you need to have your furnace and any gas appliances checked by a professional before you go back to your home.
  • Call your healthcare provider right away or return to the emergency department if:
    • Your symptoms are getting worse, not better.
    • You start to have the same symptoms that made you seek treatment.
    • You have any symptoms that worry you.

How can I prevent carbon monoxide poisoning?

  • Have fuel-burning appliances such as oil and gas furnaces, gas water heaters, gas ranges and ovens, gas dryers, gas or kerosene space heaters, fireplaces, and wood stoves inspected by a trained professional at the beginning of every heating season. Make sure that the flues and chimneys are connected, in good condition, and not blocked.
  • Choose appliances that vent their fumes to the outside whenever possible, have them properly installed, and maintain them according to manufacturers' instructions.
  • Always have a window or door open to allow fresh air to get in when you are using a heater that uses gas or kerosene.
  • Don't keep a car running in a garage, even if the garage door to the outside is open. Fumes can build up very quickly in the garage. Fumes will also build up in the living area of your home if the garage is attached.
  • Keep the exhaust system of your car in good repair.
  • Don't use a gas oven to heat your home, even for a short time.
  • Never use a charcoal grill indoors, not even in a fireplace.
  • Don't sleep in any room or space with an unvented gas or kerosene space heater.
  • Don't use any gas-powered engine, such as a mower, weed trimmer, snow blower, chain saw, small engine, or generator, in an enclosed space.
  • Consider placing carbon monoxide alarms on each level of your home and in your bedrooms. Several different and relatively inexpensive detectors are available in stores. They will sound an alarm if the carbon monoxide level in your home is too high.
  • Don't ignore symptoms, particularly if more than one person is feeling them. You could lose consciousness and die if you do nothing.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.


HIA File emer4944.htm Release 13/2010

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