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What is Carbon Monoxide Poisoning?

When you breathe in carbon monoxide, the gas binds to hemoglobin in your blood. This prevents your blood from carrying oxygen to vital organs in your body. Carbon monoxide poisoning can damage your brain and heart and can be lethal. Brain damage can happen even after the poisoning has stopped. The Centers for Disease Control and Prevention (CDC) estimate that more than 400 people die every year from carbon monoxide poisoning in the United States. In addition, more than 50,000 people are seen in hospital emergency departments with carbon monoxide poisoning.


Common symptoms of carbon monoxide poisoning include the following:

  • Headaches
  • Dizziness
  • Weakness
  • Upset stomach
  • Vomiting
  • Chest pain
  • Confusion
  • Loss of consciousness

Carbon monoxide is especially dangerous to people who are asleep or intoxicated and might not notice symptoms or are unable to rescue themselves. People with existing heart or brain damage, children, and unborn babies are most vulnerable to carbon monoxide poisoning, but even healthy individuals can have permanent brain and sometimes heart damage from poisoning.

When to See a Doctor

Carbon monoxide poisoning is a life-threatening emergency. If you suspect that you or another person has been poisoned by carbon monoxide, go to an area with fresh air and call 911 immediately.


Common sources of carbon monoxide include:

  • Motor vehicles
  • Wood stoves
  • Fireplaces
  • Furnaces
  • Water heaters
  • Generators
  • Gas stoves and ovens
  • Dryers

Carbon monoxide poisonings are a year-round threat, but are more common in the winter months when more fuel-burning devices are in use.

Diagnosis and Tests

Carbon monoxide poisoning is diagnosed based on a patient’s symptoms and reports of breathing too much carbon monoxide. Blood tests for elevated levels of carbon monoxide in the blood (e.g. carboxyhemoglobin), can confirm poisoning, but even if this blood test is normal, poisoning may have occurred.


If you suspect someone has carbon monoxide poisoning, move the person to a ventilated area immediately and call 911. When Emergency Medical Services (EMS), arrive, providers will give the person supplemental oxygen and monitor them. If necessary, they will transport the person to a hospital.

At the Emergency Department, high-flow oxygen will be given and the person will be evaluated for heart injury. Some patients require treatment with hyperbaric oxygen inside a pressurized chamber. Oxygen therapy removes carbon monoxide from the patient’s blood and tissue more quickly. Hyperbaric oxygen does this even faster rate and also prevents damage caused by inflammation from the poisoning. Some patients need more than one hyperbaric oxygen treatment.

Even with prompt therapy, some patients can have ongoing problems and may need additional evaluation and treatment days to months later. Some will have permanent brain damage, and less commonly heart damage from carbon monoxide poisoning.


Carbon monoxide poisoning is preventable. There are some simple measures to help prevent carbon monoxide poisoning:

  • Install carbon monoxide alarms inside your home. Even if you do not have a gas-source in your home install carbon monoxide alarms. Poisoning has even occurred by carbon monoxide from a source outside the home.
  • Have your furnace and hot water heater inspected annually.
  • Never operate engines indoors. If your car is located in a garage, open the garage door, then start the car and drive it out of the garage immediately.
  • Generators have resulted in the deaths of hundreds of patients and considerable harm to survivors. Never operate a generator inside a home, garage, warehouse, boat, camper, or any other enclosed space.
  • Never water ski directly behind a boat as very high levels of carbon monoxide accumulate there.
  • When camping do not operate propane equipment inside a tent or camper, unless it is adequately ventilated. Also, carry a portable carbon monoxide alarm.
  • Unfortunately even hotels with boiler and heater problems have caused carbon monoxide poisoning, including death. Consider carrying a portable carbon monoxide alarm when you travel.
  • Use household appliances as recommended and make sure they are properly vented

Carbon monoxide is a gas that you can’t see or smell. It comes from burning carbon-based fuel such as natural gas, gasoline, diesel, wood, propane, or charcoal. Cars, trucks, fireplaces, and furnaces produce carbon monoxide. If carbon monoxide is produced in an area that isn’t open to the outside (ventilated), any people in that area can be poisoned by breathing too much of the gas. This can happen if a fireplace or furnace stops working correctly. Carbon monoxide poisoning can be a life-threatening emergency. Learn more about carbon monoxide poisoning and what you can do to protect yourself and your family.