Guard Against Carbon Monoxide

Keep the Chimney Clear, Install a Detector to Prevent Poisoning in Your Home

When you think of the dangers of carbon monoxide poisoning, you might think of fires or mine accidents. But the deadly gas can also be an everyday threat.

If you don't have and properly use a carbon monoxide detector, something as simple and sweet-sounding as birds nesting in your chimney may cause problems. Birds? They nest in places with warm air during the colder months, as humans do. But when they snuggle up in your chimney, they block the flue and thus inhibit circulation of fresh air into your home.

And that allows carbon monoxide to build up. Because carbon monoxide is odorless, colorless and tasteless, it can sneak up on you and accumulate in your system. You may feel as if you have been bitten by a flu bug, but carbon monoxide can kill you. By the time you feel ill, you have already breathed in toxic levels and need to get some fresh air -- fast.

The Consumer Product Safety Commission and Consumer Reports say that hundreds of Americans die each year from carbon monoxide poisoning. Thousands more end up in hospitals for treatment. Sources include fuel-burning appliances (furnaces, ranges, water heaters and room heaters), charcoal burned inside a house, garage or other enclosed space, or cars left idling in attached garages.

Poorly functioning, leaking or blocked ventilation systems of these units cause carbon monoxide to seep into rooms, risking harm to occupants.

Carbon monoxide is deadly because, when inhaled, it interferes with oxygen intake, which explains the flu-like symptoms: headache, fatigue, shortness of breath, nausea and dizziness.

"Babies, children, pregnant women, people with circulatory or respiratory ailments and the elderly are more sensitive to carbon monoxide than healthy adults," said John Burger, battalion chief of the D.C. fire department.

Sources vary on the exact level of exposure that causes problems. Burger said carbon monoxide exposure above 35 parts per million (ppm) over several hours is dangerous, and levels over 200 ppm are fatal in minutes.

The consumer product commission's Web site says symptoms of headache, fatigue or nausea may appear at carbon monoxide exposure above 70 ppm and "disorientation, unconsciousness and death" above 150 ppm to 200 ppm. On its Web site, Consumer Reports says there is danger of unconsciousness and death at 400 ppm.

Avoid problems by being aware of the threat, limiting exposure and using detectors.

In the Washington area, carbon monoxide detectors generally aren't required by law, although they are in some other municipalities and states, including New Jersey, New York and Massachusetts. Consumer safety groups and fire departments, however, strongly recommend them.

Not all detectors are the same. They range in price from about $10 to about $200, depending upon what you buy and where.