by Wood D


Carbon monoxide poisoning can be fatal. It happens after inhaling carbon monoxide (CO) gas. CO is an odorless, tasteless and colorless gas. It can be easily inhaled without anyone knowing about it. This gas is released when gas, wood, coal or other fuels are burned. Gas cookers, faulty heaters, and poor ventilation are common causes.

Carbon Monoxide Binding to Hemoglobin
Nucleus factsheet image
Copyright © Nucleus Medical Media, Inc.


Carbon monoxide poisoning is caused by inhaling CO gas. Exposure can happen when any gas appliance is faulty or poorly ventilated such as:

  • Hole in ventilation pipes
  • Motor vehicle engines that are left running inside an enclosed garage
  • Barbecue grills, gas grills, or camp stoves used inside your home, garage, or basement
  • Power generators used inside your home, garage, or basement

CO is easily absorbed through the lungs. It binds to things in the blood and takes the place of the oxygen. The body does not get enough oxygen to function. Brain cells are at highest risk of damage.

Risk Factors

Carbon monoxide poisoning is more common in infants or older people. Other factors that may increase your risk of carbon monoxide poisoning include:

  • Living in a cold external environment
  • Having a heart or lung condition
  • Exposure to faulty appliances or ventilation


Symptoms related to carbon monoxide poisoning are usually vague. They can be split into acute (immediate) and chronic symptoms.

Acute Symptoms

  • Shortness of breath
  • Wheezing
  • Cough
  • Hoarse voice

Chronic Symptoms

  • Racing heartbeat
  • Chest pain
  • Nausea or vomiting
  • Headache
  • Numbness and tingling
  • Vision problems
  • Loss of appetite
  • Sleep problems
  • Dizziness
  • Tiredness
  • Memory loss
  • Reduced sex drive


The doctor will ask about symptoms and past health. A physical exam will be done. Tests may include:

  • Blood tests—to measure
    • Carboxyhemoglobin test—to show severity of exposure and track treatment progress
    • Oxygen levels
    • Electrolytes
  • Chest x-ray —to see if pneumonia is present
  • Electrocardiogram (EKG)—to check the heart's electrical activity and look for signs of heart damage


Before medical care:

Stay away from the source of the carbon monoxide. Breathe fresh air outdoors. Mild symptoms usually improve after getting away from the gas.

Always seek medical care at the closest emergency room. The doctor will give you oxygen until your symptoms go away and carbon monoxide levels in your blood drop.

Other therapies may include:

  • Ventilator—to assist in breathing for people in a coma, or who have serious heart or nerve problems
  • Hyperbaric oxygen therapy —a special chamber in which oxygen is given under greater pressure than normal


CO has no odor or color, you will not know if it is present. The following can reduce your chance of exposure:

  • Have an expert check your fireplace chimney every year. Debris can block vents and cause a build-up of carbon monoxide.
  • Have a professional check gas and kerosene appliances before heating season.
  • Make sure all gas and combustion appliances are vented to the outdoors. Check ventilation pipes for holes.
  • Do not use a gas stove or oven to heat the house.
  • Do not use a barbecue grill, camp stove, or unvented kerosene heater inside a house or tent.
  • Do not use generators or other gasoline-powered engines indoors.
  • Choose equipment that carries the seal of the American Gas Association or the Underwriters' Laboratory.
  • Install a carbon monoxide detector. Follow manufacturer's directions for installation and maintenance. Only use detector as a backup, in addition to other safety steps.
  • Have car's exhaust system checked every year.
  • Do not run the car in the garage, especially with the door closed. Start the car and take it outside.
  • Do not leave the door from the garage to the house open when the car engine is running.


US Consumer Product Safety Commission 

US Environmental Protection Agency 


Health Canada 

Public Health Agency of Canada 


Indoor air quality. Environmental Protection Agency website. Available at: Accessed September 25, 2020.

Breimer LH, Mikhailidis DP. Could carbon monoxide and bilirubin be friends as well as foes of the body? Scand J Clin Lab Invest. 2010;70(1):1-5.

Carbon monoxide poisoning. Centers for Disease Control and Prevention website. Available at: Accessed September 25, 2020.

Carbon monoxide toxicity. EBSCO DynaMed website. Available at:  . Accessed September 25, 2020.

Juurlink DN, Buckley NA, et al. Hyperbaric oxygen for carbon monoxide poisoning. Cochrane Database Syst Rev. 2005;(1):CD002041.

Weaver LK, Hopkins RO, et al. Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med. 2002; 347:1057-1067.

World Health Organization (WHO) Study Group on Tobacco Product Regulation. Waterpipe tobacco smoking: health effects, research needs and recommended actions by regulators. World Health Organization website. Available at: Accessed September 25, 2020.

Revision Information