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Carbon monoxide poisoning

Carbon monoxide is an odorless gas that causes thousands of deaths each year in North America. Breathing in carbon monoxide is very dangerous. It is the leading cause of poisoning death in the United States.

This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or a local poison control center at 1-800-222-1222.

Poisonous Ingredient

Carbon monoxide is a chemical produced from the incomplete burning of natural gas or other products containing carbon.

Where Found

The following items may produce carbon monoxide:

  • Anything that burns coal, gasoline, kerosene, oil, propane, or wood
  • Automobile engines
  • Charcoal grills (charcoal should never be burned indoors)
  • Indoor and portable heating systems
  • Portable propane heaters
  • Stoves (indoor and camp stoves)
  • Water heaters that use natural gas

Note: This list may not be all inclusive.


When you breathe in carbon monoxide, the poison replaces the oxygen in your bloodstream. Your heart, brain, and body will become starved of oxygen.

Symptoms vary from person to person. Those at high risk include young children, the elderly, people with lung or heart disease, people who are at high altitudes, and smokers. Carbon monoxide can harm a fetus (unborn baby still in the womb).

Symptoms of carbon monoxide poisoning may include:

Animals can also be poisoned by carbon monoxide. People who have pets at home may notice that their animals become weak or unresponsive from carbon monoxide exposure. Often the pets will get sick before humans.

Home Care

If the person breathed in the poison, immediately move him or her to fresh air. Seek immediate medical help.


Install a carbon monoxide detector on each floor of your home. Place an additional detector near any major gas-burning appliances (such as a furnace or water heater).

Many carbon monoxide poisonings occur in the winter months when furnaces, gas fireplaces, and portable heaters are being used and windows are closed. Have heaters and gas-burning appliances regularly inspected to make sure they are safe to use.

Before Calling Emergency

The following information is helpful for emergency assistance:

  • Person's age, weight, and condition (for example, is the person awake or alert?)
  • How long they may have been exposed to the carbon monoxide, if known

However, DO NOT delay calling for help if this information is not immediately available.

Poison Control

In the United States, call 1-800-222-1222 to speak with a local poison control center. This hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. You can call 24 hours a day, 7 days a week.

What to Expect at the Emergency Room

The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. The person may receive:

  • Airway support, including oxygen, breathing tube through the mouth (intubation), and breathing machine (ventilator)
  • Blood and urine tests
  • Chest x-ray
  • EKG (electrocardiogram, or heart tracing)
  • Fluids through a vein (intravenous or IV)
  • Hyperbaric oxygen therapy (high-pressure oxygen given in a special chamber)
  • Medicines to treat symptoms

Outlook (Prognosis)

Carbon monoxide poisoning can cause death. For those who survive, recovery is slow. How well a person does depends on the amount and length of exposure to the carbon monoxide. Permanent brain damage may occur.

If the person still has impaired mental ability after 2 weeks, the chance of a complete recovery is not very good. Impaired mental ability can reappear after a person has been symptom-free for 1 to 2 weeks.


Kao LW. Toxicity associated with carbon monoxide. Clin Lab Med. 2006;26(1):99-125.

Nelson LS, Hoffman RS. Inhaled toxins. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 159.

Sather JE . Toxins. Anesthesiol Clin North America. 2006;24(3):647-670.

Update Date 1/25/2015

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