Carbon monoxide

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Families and Communities Health Professionals

Carbon monoxide (CO) is a toxic, colorless, odorless, tasteless, and flammable gas produced by the incomplete burning (in appliances, heaters, etc) of various fuels, including coal, wood, charcoal, oil, kerosene, propane, and natural gas. It is a major component of car exhaust.

CO can quickly become unsafe in enclosed or semi-enclosed areas with poor ventilation. This toxic gas can enter living spaces through poorly functioning windows or vents.

CO poisonings often occur during power outages related to natural disasters and severe storms due to unsafe use of generators indoors, in semi-enclosed spaces or near windows and doors. As natural disasters and severe storms increase due to climate change, understanding how to safely use generators is important.

Carbon Monoxide Poisoning

Sources of CO include:

Furnaces, fireplaces, and wood stoves
Pressure washers and gas-powered tools
Certain swimming pool heaters (gas/propane)
Portable heaters (kerosene/gas/propane)
Hot water heaters (gas)
Paint stripping chemicals
Dryers (gas)
Stoves/grills (kerosene/gas/propane/charcoal)
Anything with an internal combustion engine (cars, chainsaws, snowblowers, etc)

The most common symptoms of CO poisoning are headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion. Exposure to carbon monoxide can cause loss of consciousness and death. If you think someone is suffering from carbon monoxide poisoning, get them to fresh air and call 911 for assistance. Make sure other people in the same area are safe. Go to the emergency room for care.

Families and Communities

If you're concerned about carbon monoxide, talk with your pediatrician.

Families can keep their homes safer by

Having a working smoke detector and CO detector in the home. Make sure you:
- Install a detector near every sleeping area
- Test monthly
- Clean regularly, suggested monthly
- Replace batteries as recommended by the manufacturer. (Be sure to read the instructions!)
Having your home heating system checked by a trained professional each year.
Making sure that furnaces and gas fireplaces are properly vented and there are no obstructions to the exhaust pipe.
Making sure that wood stoves and fireplace chimneys are cleaned and comply with all state and local regulations for installation.
Not using a gas range or oven to heat your home.
Not using a charcoal grill, hibachi grill, lantern, or portable camping stove inside a home, tent or camper.
Not using gas or kerosene heaters indoors without proper venting to the outside.
Never run a generator, pressure washer, or any gasoline-powered engine inside a basement, garage, or other enclosed structure. Even if the doors or windows are open.
Keeping vents and flues free of trash, especially if winds are high. Flying trash can block ventilation lines.
Running any motor vehicle, generator, pressure washer, or any gasoline-powered engine outside at least 15 feet from any open window, door, or vent where exhaust can drift into an enclosed area.
Avoid leaving the motor running in a car/vehicle parked in a closed or partially closed space, such as a garage. Make sure that car exhaust pipes are clear of snow or mud so fumes will not go back into the vehicle.
For power outages, it is safest to use permanently installed generators instead of portable generators. A qualified electrician should install a power transfer switch. Portable generators should only be used for emergencies and should always be located outside a residence. Read more about the safe use of generators during a power outage.

Your regional Pediatric Environmental Health Specialty Unit (PEHSU) has staff who can also talk with clinicians and/or parents about concerns over environmental toxins.

To download this page as a fact sheet, click here. Also, visit the educational resources from the Centers for Disease Control and Prevention for more information.

Community leaders can help keep their community safe by

Reviewing local disaster plans to make sure they have safe housing options and encourage families to seek shelter rather than try to heat their location unsafely.
Educating the public on the dangers and symptoms of carbon monoxide poisoning.
Asking your department of health to notify exposures with families and community leaders.
Influencing housing policy and encouraging landlords to choose and use heating appliances wisely. They can also properly install, maintain, ventilate and regularly check all fuel-fired heating systems, water heaters, appliances, fireplaces, wood and coal stoves, and space heaters.

For more information:

Health Professionals

Symptoms of CO poisoning are often non-specific and without correlation to the level of exposure. The overlapping symptoms may lead to the misdiagnosis of acute or chronic CO poisoning as a case of “bad flu”, but CO poisoning patients are classically afebrile. Clinicians should have a high index of suspicion of CO poisoning, especially if several members in the same household present with similar clinical findings.

Acute symptoms and Chronic symptoms

Acute symptoms	Chronic symptoms
Headaches, dizziness, weakness, drowsiness, nausea, and vomiting Dyspnea on exertion, palpitations, confusion Irritability, irrational behavior, slurred speech, loss of consciousness, coma, and eventual death.	Neurological and cognitive deficits Chronic fatigue, emotional distress, difficulty working, sleep disturbances, memory loss, vertigo, neuropathy, paresthesia, recurrent infections, polycythemia, abdominal pain, and diarrhea

How to Diagnose and Evaluate CO Poisoning?

Environmental assessment and patient history is critical to distinguish CO poisoning from other indoor air pollutants. Consider:

Housing situation (age of the house, use of flame-based heating elements (e.g. oil, propane, gasoline, natural gas) or gas-fired electricity generators)
Similar symptoms of others in the household

Patients should be examined for other conditions, including smoke inhalation, trauma, medical illness, or intoxication. A neurological exam should include an assessment of age-appropriate cognitive function.

Direct measurement of blood COHgb using a transcutaneous co-oximeter can also be used to diagnose CO poisoning. Patients with significant COHgb levels can have normal readings on a regular pulse oximeter. Normal COHgb levels in non-smokers can range from 1-2%. Cigarette smokers' levels can range from 5-10%.

Check out the carbon monoxide handout from the Region 9 Pediatric Environmental Health Unity Prescription for Prevention series.

Try this short flier from the CDC, or this longer set of FAQs.

The PEHSU Environmental Toolkit provides anticipatory guidance by age.

Tailor the Carbon Monoxide Prescription for Prevention to your region.

Updated July 9, 2024

Funder Disclaimer

The Pediatric Environmental Health Specialty Units (PEHSU) are supported by cooperative agreement FAIN: NU61TS000356 with the Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry (CDC/ATSDR). The U.S. Environmental Protection Agency (EPA) also provides support through Inter-Agency Agreement 24TSS2400078 with CDC/ATSDR. The Public Health Institute supports the PEHSU as the National Program Office. The content on this website has not been formally disseminated by CDC/ATSDR or the EPA and should not be construed to represent any agency determination or policy. Use of trade names that may be mentioned is for identification only and does not imply endorsement by the CDC/ATSDR or EPA.

The information contained on this website should not be used as a substitute for the medical care and advice of your/your child’s primary care provider. There may be variations in treatment that your provider may recommend based on individual facts and circumstances.