Carbon monoxide (CO) poisoning happens when you breathe in fumes that contain CO. You can get very sick or even die if you breathe high levels of CO for even a few minutes.
Carbon monoxide (CO) is a gas produced when gasoline and other fuels burn. It is invisible and colorless. You can’t smell or taste it. CO can build up quickly and is dangerous in high levels.
Carbon monoxide is in fumes (smoke) from:
Red blood cells carry oxygen throughout your body. Your organs need oxygen to live. But red blood cells take in carbon monoxide faster than oxygen. At high levels, CO crowds out oxygen in your bloodstream.
If you breathe too much CO, organs such as your brain and heart don’t get enough oxygen. CO can also combine with proteins in the body and damage your cells and organs. If you inhale a lot of CO, you can lose consciousness (pass out) and suffocate within minutes.
Each year in the United States, accidental CO poisoning:
Everyone is at risk for carbon monoxide poisoning. In winter, risks are higher because of improperly maintained heating systems or people warming up cars in garages. At highest risk are:
People who have CO exposure through their jobs are also at higher risk. Harmful CO levels exist in places such as boiler rooms, warehouses or petroleum refineries. Occupations with high CO levels include:
Many appliances and vehicles burn fuel and emit (release) carbon monoxide. When people use and maintain these appliances correctly, the CO levels usually aren’t harmful.
CO poisoning happens when people use fuel-burning appliances without proper ventilation or in other unsafe ways. For example, it can be dangerous if you:
The symptoms of low levels of CO exposure are similar to flu symptoms or food poisoning:
Moderate CO exposure can cause symptoms such as:
Your healthcare provider can do a blood test soon after CO exposure to detect carbon monoxide poisoning. The test doesn’t show how severe the poisoning was or if you’ll have long-term health problems.
Your provider will figure out the best treatment for you based on:
If you suspect you have been exposed to carbon monoxide, or you have carbon monoxide poisoning symptoms, call 911 or get to an emergency room as soon as possible. You’ll be given an oxygen mask to breathe through to provide pure oxygen. This will offset the carbon monoxide buildup.
If you suspect a CO buildup or you’re experiencing symptoms of carbon monoxide poisoning, exit the area immediately and seek fresh air. You can take preventive steps to help safeguard your health:
Do a yearly inspection: At the beginning of each heating season, hire a trained professional to inspect your fuel-burning appliances, including:
Use appliances safely: In addition to a yearly inspection, make sure to:
Install a carbon monoxide detector: Install a battery-operated (or battery backup) CO detector in your home. You should:
To lower your risk of CO poisoning, don’t:
Prompt treatment can reverse the effects of CO poisoning. However, there is a risk of permanent damage to the brain and heart, which need a lot of oxygen.
CO poisoning can also damage the reproductive system and an unborn baby. Both have rapidly dividing cells that need a steady supply of enough oxygen.
CO poisoning can be fatal. A person who is sleeping or otherwise unconscious (such as after drinking too much alcohol) can sometimes die before experiencing any symptoms. It’s important to have working CO detectors in your home to protect you while you sleep.
If you catch CO poisoning in time, treatment can reverse the effects. You may experience lingering impacts, so make sure to follow your healthcare provider’s recommendations.
Never ignore a CO alarm. When the alarm sounds:
If you received treatment for CO poisoning, ask your healthcare provider:
A note from Cleveland Clinic
Carbon monoxide (CO) poisoning can become deadly in a matter of minutes. If you suspect CO poisoning, leave your home or building immediately and call 911 or go to the emergency room. If treated quickly, the effects of CO poisoning can be reversed.
The best way to avoid CO poisoning is to follow safety guidelines. Place a CO detector in your home and have your gas appliances checked yearly. With the right precautions, you can keep yourself and your family safe and healthy. Talk to your healthcare provider if you’ve been exposed to carbon monoxide.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 08/24/2020