U.S. Department of Health & Human Services


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If someone is unconscious or has trouble breathing, call 911.


Carbon Monoxide (CO)

Carbon Monoxide (CO)

What is carbon monoxide (CO) and where does it come from?

Carbon monoxide (CO) is a gas that is poisonous. It has no color or smell. Cars, appliances, furnaces, and gas dryers can give off CO.

How does CO poison people?

CO takes the place of oxygen in the blood. Without oxygen, the heart, lungs, brain, and other body parts cannot work properly. Signs of CO poisoning are similar to flu symptoms. They include upset stomach, tiredness, and headaches. If CO poisoning is not treated, it can cause seizures and even death. 

What should I do if I think I have been exposed to CO?

Immediately go outside to get fresh air, and right away call Poison Help (1-800-222-1222), which connects you to your local poison center. If you feel better when you are out of your home and worse when you return, CO may be present. If you notice this, call 911. Have the fire department check for CO in your house. If CO is present, the source must be repaired before it is safe to return home.

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