What is carbon monoxide?

Carbon monoxide is a colorless, odorless, and tasteless gas which is highly poisonous. The chemical formula for carbon monoxide is CO, one molecule of carbon and one molecule of oxygen. Under high pressure, it becomes a liquid. It is produced by the incomplete burning of natural gas, gasoline, liquefied petroleum gas, oil, kerosene, coal, charcoal, or wood. Appliances that use these fuels may also produce carbon monoxide. 

Running motor vehicles and tobacco smoke also produce carbon monoxide. Other sources of carbon monoxide include unvented kerosene and gas space heaters; leaking chimneys and furnaces; gas stoves; back-drafting from furnaces, gas water heaters, wood stoves, and fireplaces; and automobile exhaust, especially in closed garages. 

Carbon monoxide is used to separate metals from their ores and make other chemicals, including phosgene. It is used in blast furnaces.

The most common source of carbon monoxide exposure is motor vehicle exhaust. You can be exposed to carbon monoxide at home if your appliances that burn fuel are not operating correctly, if your appliances are not vented, or if your chimneys, vents, and flues are blocked or damaged. 

You can be exposed if you leave your car running in a garage, use stoves or clothes dryers for heating your home, or breathe tobacco smoke. Exposure to carbon monoxide can come from burning charcoal or using portable fuel-burning camping equipment inside your home, garage, vehicle, or tent. Exposure can also come from using gasoline-powered tools and engines indoors. 

You can be exposed to carbon monoxide at work if you operate gasoline-powered machinery or vehicles in an enclosed space. You can also be exposed if you are a firefighter, traffic police officer, coal miner, toll booth operator, or transportation mechanic, and if you work with blast furnaces, smelters, coke ovens, or processes that use carbon monoxide.

Exposure to very high concentrations of carbon monoxide can cause convulsions, coma, and death through carbon monoxide poisoning. Exposure to high levels can cause impaired vision and coordination, unconsciousness, headaches, dizziness, confusion, vomiting, muscle weakness, and nausea. 

If you are pregnant, exposure to carbon monoxide may cause miscarriage or increase the risk of damage to a developing fetus; it may also result in babies with low birth weights and nervous system damage. Carbon monoxide poisoning can occur sooner in young children; pregnant women; elderly people; people with anemia, lung disease, or heart disease; people at high altitudes; or people who smoke cigarettes. 

Exposure to low levels of carbon monoxide can cause fatigue, chest pain, shortness of breath, memory loss, skin lesions, sweating, and flu-like symptoms. In the long term, exposure to low levels can cause heart disease and damage to the nervous system. Skin contact with liquid carbon monoxide in the workplace can cause frostbite. 

If you think you have been exposed to carbon monoxide, contact your health care professional. 

For poisoning emergencies or questions about possible poisons, please contact your local poison control center at 1-800-222-1222.

Locations where Carbon Monoxide may be found
City	Farm	Town	U.S.-Mexico Border	Port
Airplanes and Air Travel Construction Factory Food Services Homes Hospital Offices and Stores Outdoor Air Park School School Bus Vehicles	Barn and Silo Homes Off-road Vehicles Outdoor Air Shed Tree Farm and Logging Vehicles	Factory Homes Offices and Stores Outdoor Air Park School School Bus Vehicles	Auto Shop Border Crossing Homes Illegal Dumps and Tire Piles Maquiladora Outdoor Air Park Tienda Trash Burning Vehicles	Beach Cruise Ship Homes Marina and Boats Offices and Stores Outdoor Air Shipping Shipyard Vehicles

Last Updated: November 06, 2008