What is carbon monoxide? Carbon monoxide, or CO, is an odorless, colorless and toxic gas. Because you cannot see it or smell it, it can kill you before you are even aware of its presence. Carbon monoxide is one of the leading causes of accidental poisoning deaths in America.

What are sources of carbon monoxide emission? Carbon monoxide is a product of incomplete combustion. Therefore, anything that burns gasoline, kerosene, oil, propane, wood or coal produces carbon monoxide. Any improperly maintained or unvented equipment such as automobile engines, generators, furnaces, portable space heaters, wood stoves or charcoal grills can produce high levels of carbon monoxide in indoor spaces.

What are the symptoms of carbon monoxide poisoning? The most common symptoms of carbon monoxide poisoning include headache, dizziness, nausea, chest pain and confusion. High levels of carbon monoxide exposure can cause unconsciousness and death.

Who is at risk? While all people and animals are at risk, infants and people with chronic heart disease or respiratory problems are particularly susceptible to carbon monoxide's effects.

How to avoid carbon monoxide poisoning: Many poisonings occur during the winter months when heaters are in high use and windows are closed. Here are some steps to reduce carbon monoxide exposure.

• Ensure that combustion equipment is properly installed and maintained regularly.
• Never use a generator inside living/working space.
• Never run a car or truck in the garage with the door shut.
• Never burn charcoal indoors.
• Never use a gas range or oven for heating.
• Install a carbon monoxide detector in your home and check batteries regularly.
• Purchase only gas equipment containing the seal of a national testing agency such as Underwriters Laboratory (UL) or the American Gas Association (AGA).

Levels in Homes: Average carbon monoxide levels in homes without gas stoves may vary from 0.5 to 5 parts per million, or ppm. In homes with properly maintained gas stoves, carbon monoxide levels range from 5 to 15 ppm. However, when a gas stove is not properly maintained, the carbon monoxide level may exceed 30 ppm.

Poison Control: In the unlikely event someone may have been overexposed to carbon monoxide, the United States maintains a national poison control center 24 hours a day, 7 days a week. Individuals who call the center will be put in touch with a poison control expert.

For more information about carbon monoxide poisoning, call the National Poison Control Center at 1-800-222-1222, or visit these websites:

U.S. Centers for Disease Control and Prevention, http://www.cdc.gov/co/default.htm

Environmental Protection Agency, http://www.epa.gov/iaq/co.html