Carbon monoxide (CO) is a colorless, odorless gas that can poison you and kill you if there is too much of it in the air you breathe. Hundreds of people die accidentally every year from CO poisoning. Infants, older adults, and people with anemia or heart or lung disease are particularly sensitive to high levels of CO.

Carbon monoxide poisoning is caused by breathing high levels of CO. When this happens, your body does not get enough oxygen. You may become unconscious and your brain may be permanently damaged if you survive.

CO is produced by the burning of fuels such as natural gas, gasoline, oil, kerosene, wood, or charcoal. If appliances, such as a gas stove or furnace, are not working properly or are used incorrectly, poisonous levels of CO may result. The level of CO may also become too high by the burning of fuel, such as by a gas or kerosene heater, in an area that is not properly ventilated. For example, levels of CO may build up in a house when these heaters are used in an attached garage and the garage door is closed, even if the door between the house and garage is closed.

Many of the symptoms of CO poisoning are like the symptoms of mild stomach flu or food poisoning. Symptoms include:

• shortness of breath
• mild nausea
• headache
• dizziness
• confusion
• fainting.

If you continue to be exposed to high levels of CO, you may die.

If you are sleeping when the CO levels become too high, you may not wake up to have any symptoms. This is why it is so important to use proper heating and ventilation in your home.

If you are having symptoms of CO poisoning, you may not realize that CO is the cause. If you have symptoms only in your house, or if they go away or lessen when you leave home and come back when you return, you should suspect CO poisoning. Also suspect carbon monoxide if others in your household have similar symptoms, especially if everyone's symptoms started at about the same time.

If you have symptoms that you think could be caused by CO poisoning:

• Get fresh air right away. Open doors and windows, turn off appliances and heaters, and get everyone out of the building.
• Call 911 or have someone take you to an emergency room and tell them you suspect CO poisoning. CO poisoning can be diagnosed by a blood test if it is done soon after exposure to CO. You will be given oxygen to treat carbon monoxide poisoning.

Have fuel-burning appliances such as oil and gas furnaces, gas water heaters, gas ranges and ovens, gas dryers, gas or kerosene space heaters, fireplaces, and wood stoves inspected by a trained professional at the beginning of every heating season. Make sure that the flues and chimneys are connected, in good condition, and not blocked. Choose appliances that vent their fumes to the outside whenever possible, have them properly installed, and maintain them according to manufacturers' instructions.

Don't keep a car running in a garage, even if the garage door to the outside is open. Fumes can build up very quickly in the garage. Fumes will also build up in the living area of your home if the garage is attached. Don't use a gas oven to heat your home, even for a short time. Never use a charcoal grill indoors. Don't sleep in any room or space with an unvented gas or kerosene space heater. Don't use any gas-powered engines (mowers, weed trimmers, snow blowers, chain saws, small engines, or generators) in an enclosed space.

Consider placing carbon monoxide alarms on each level of your home and in your bedrooms. Several different and relatively inexpensive detectors are available in stores. They will sound an alarm if the carbon monoxide level in your home is too high.