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How to prevent carbon monoxide poisoning

Know the common sources and symptoms, immediate treatment options, and how to prevent CO poisoning


Have your heating system, water heater, and any other gas, oil, or coal burning appliances serviced by a qualified technician every year.

If you think you or someone else has been exposed to CO, stop reading, get into fresh air, and call 9-1-1.

Carbon monoxide (CO) poisoning is not only common, but it can be fatal. Approximately 50,000 people in the U.S. visit the emergency department each year due to accidental CO poisoning, and 430 people die of accidental CO poisoning.

The following information and frequently asked questions have been compiled from CO resources produced by the U.S. Department of Labor Occupational Safety and Health Administration (OSHA), the Centers for Disease Control and Prevention (CDC) and the Mayo Clinic.

Consider the best ways to share this information and CO-focused resources with your community.

What is CO?

CO is a colorless, odorless and tasteless gas. The gas is a common industrial hazard resulting from the incomplete burning of material containing carbon. This includes natural gas, gasoline, kerosene, oil, propane, coal or wood. CO is found in fumes produced from burning fuel in cars or trucks, small engines, stoves, lanterns, grills, fireplaces, gas ranges or furnaces. The amount of CO produced by these sources usually isn’t cause for concern; however, if they’re operated in a closed or partially enclosed space, the CO can build to dangerous levels and can prove fatal to anyone breathing in the space.

How does CO poisoning occur?

CO poisoning is caused by inhaling these combustion fumes. The CO displaces oxygen in the blood and deprives the heart, brain and other vital organs of oxygen. This can lead to serious tissue damage, or even death. Large amounts of CO can overcome an individual in minutes without warning, causing loss of consciousness and suffocation. Smoke inhalation during a fire also can cause CO poisoning.


What are the risks of CO poisoning?

Depending on the degree and length of exposure, carbon monoxide poisoning can cause:

  • Permanent brain damage
  • Damage to your heart, possibly leading to life-threatening cardiac complications
  • Fetal death or miscarriage
  • Death

What are the symptoms of CO poisoning?

CO symptoms are often described as “flu-like.” While symptoms can vary from person to person, there are several common signs of CO poisoning:

  • Headache
  • Dizziness/blurred vision
  • Fatigue/weakness
  • Drowsiness
  • Nausea/upset stomach
  • Shortness of breath/tightness across the chest

During prolonged or high exposures, symptoms may worsen to include vomiting, confusion and collapse in addition to loss of consciousness and muscle weakness. Sudden chest pain may occur in people with angina.

How is CO poisoning treated?

CO poisoning can be reversed if caught in time. CO dissipates in fresh air where it is not allowed to accumulate. If you think you or someone else has been exposed to CO, get into fresh air and call 9-1-1.

Emergency personnel can treat CO patients with high concentrations of oxygen to begin the process of bumping CO molecules off the hemoglobin cells.

In more severe cases of CO poisoning, a facility that has access to a hyperbaric chamber may be needed. Oxygen under increased atmospheric pressure will help drive more CO off the hemoglobin.

Who is at risk of CO poisoning?


Each year, more than 400 Americans die from unintentional CO poisoning not linked to fires, more than 20,000 visit the emergency room, and more than 4,000 are hospitalized.

Individuals at greatest risk include those who work in boiler rooms, warehouses, petroleum refineries, pulp and paper production, and steel production; around docks, blast furnaces, or coke ovens; or in the following occupations:

  • Firefighter
  • Police officer
  • Welder
  • Garage mechanic
  • Carbon-black maker
  • Organic chemical synthesizer
  • Metal oxide reducer
  • Longshore worker
  • Diesel engine operator
  • Forklift operator
  • Marine terminal worker
  • Toll booth or tunnel attendant
  • Customs inspector
  • Taxi driver

CO poisoning may occur sooner in those most susceptible: infants and young children, the elderly, people with chronic lung or heart disease, people with anemia, people at high altitudes, or those who already have elevated CO blood levels, such as smokers. Additionally, CO poisoning can be particularly dangerous for people who are sleeping or intoxicated, as they can suffer irreversible brain damage or even death before anyone knows there is a problem.

How to prevent CO poisoning in the home

There are several ways to prevent CO poisoning in the home:

  • Install a CO detector: Install a battery-operated or battery back-up CO detector, and check or replace the battery when you change the time on your clocks each spring and fall. Place your detector where it will wake you up if it alarms, such as outside your bedroom. Consider buying a detector with a digital readout. This detector can tell you the highest level of CO concentration in your home in addition to alarming. Replace your CO detector every 5 years.
  • Get out: If the alarm sounds, leave the house and call 911 or the fire department.
  • Move equipment outside: Do not use portable flameless chemical heaters indoors. Never burn charcoal indoors. Burning charcoal – red, gray, black, or white – gives off CO. Never use a portable gas camp stove indoors.
  • Be smart about generators: Similarly, never use a generator inside your home, basement or garage or less than 20 feet from any window, door, or vent. Further, when using a generator, use a battery-powered or battery backup CO detector in your home.
  • Schedule annual service: Have your heating system, water heater, and any other gas, oil, or coal burning appliances serviced by a qualified technician every year. Also, have your chimney checked or cleaned every year. Chimneys can be blocked by debris. This can cause CO to build up inside your home or cabin.
  • Call an expert: If you smell an odor from your gas refrigerator, have an expert service it. An odor from your gas refrigerator can mean it could be leaking CO.
  • Buy UL-tested: When you buy gas equipment, buy only equipment carrying the seal of a national testing agency, such as UL.
  • Vent your appliances: Make sure your gas appliances are vented properly. Horizontal vent pipes for appliances, such as a water heater, should go up slightly as they go toward outdoors. This prevents CO from leaking if the joints or pipes aren’t fitted tightly.
  • Don’t use shortcut patches: Never patch a vent pipe with tape, gum, or something else. This kind of patch can make CO build up in your home, cabin or camper.
  • Only use heaters for heat: Never use a gas range or oven for heating. Using a gas range or oven for heating can cause a build up of CO inside your home, cabin or camper.
  • Ensure ventilation around solvents: Use caution when working with solvents in a closed area. Methylene chloride, a solvent commonly found in paint and varnish removers, can break down (metabolize) into carbon monoxide when inhaled. Exposure to methylene chloride can cause carbon monoxide poisoning. When working with solvents at home, use them only outdoors or in well-ventilated areas. Carefully read the instructions and follow the safety precautions on the label.
  • Get it fixed: Make repairs before returning to the site of an incident. If CO poisoning occurred in your home, find and repair the source of the CO before you stay there again. Your local fire department or utility company may be able to help.

How can I avoid CO poisoning from my car or truck?

  • Schedule a mechanic check: Have a mechanic check the exhaust system of your car or truck every year. A small leak in the exhaust system can lead to a buildup of CO inside the car.
  • Open garage doors: Never run your car or truck inside a garage that is attached to a house even with the garage door open. Always open the door to a detached garage to let in fresh air when you run a car or truck inside.
  • Mind the tailgate: If you drive a car or SUV with a tailgate, when you open the tailgate, open the vents or windows to make sure air is moving through. If only the tailgate is open, CO from the exhaust will be pulled into the car or SUV.

Visit the CO resource pages from OSHA, the CDC and the Mayo Clinic for additional information.