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Carbon monoxide (CO) poisoning has been one of the more under-publicized household hazards until two recent events put it in the spotlight. One was the accidental death in September 1994 of tennis star Vitas Gerulaitas, who succumbed to CO while sleeping in a rented home. The other was an ordinance that went into effect October 1, 1994, in Chicago requiring CO detectors in all residences heated by any fossil fuel burning equipment - in effect, all except solar or electrically heated homes. The Chicago law was in reaction to a tragedy that occurred in 1991 when a family of 10 was wiped out by CO poisoning from a faulty furnace installation.
The Consumer Product Safety Commission says that "at least" 250 people are killed each year from CO, a very conservative estimate. The American Medical Association says it's more like 1,500 people a year, with another 10,000 or more taking ill.
There is a lot of uncertainty because CO is tasteless, colorless and odorless - undetectable except by sophisticated gear. Also, the main symptoms of CO poisoning - fatigue, headaches, dizzy spells and nausea - resemble those of the flu and many other common illnesses. Thus CO poisoning is easily misdiagnosed, and people can succumb to it with very little physical discomfort, almost like falling asleep. (Early news reports treated Gerulaitas' death as mysterious and were filled with speculation about drugs or foul play.)
CO is given off by incomplete combustion of flammable fuels such as natural gas, oil, wood, coal or kerosene. Common household appliances such as furnaces, boilers, water heaters and stoves are all potential sources of CO gas. All of these products are designed with elaborate safeguards and under normal operating conditions all the CO produced from combustion will be harmlessly vented to the atmosphere.
Poor venting, due to leaks or blockages in the vent system, is the most common cause of CO build-up in the home, followed by cracks or corrosion in a furnace's heat exchanger. Here are some danger signs and steps you can take to minimize the danger:
* Most important, have your furnace or boiler regularly inspected, at least one a year, by a licensed, competent heating professional. The technician should check all connections to flue piping and vents for cracks, gaps, rust, corrosion or debris. Likewise the inspection should cover the combustion chamber and heat exchanger for cracks, holes, metal fatigue or corrosion, as well as the filters and filtering system for dirt and blockages. Debris should be cleared off the burner and safety switches tested.
* A yellow, lazy-looking flame in a natural gas furnace indicates inefficient fuel burning, and consequently higher levels of carbon monoxide. An inefficient oil furnace will give off an oily odor - but remember, you can't smell CO itself.
* Chimneys and vents ought to be inspected regularly for blockages caused by debris, animal nests or cave-ins. Also beware of cracks and holes. Inspect fireplaces for blocked flues, excess soot and debris.
* Be sure all vents are properly installed - including those leading from the clothes dryer, water heater and wood-burning stoves.
* Never use an unvented space heater indoors. Never burn charcoal inside and do not use your gas stove as a heater. When cooking, keep the oven door closed.
* Avoid running both a furnace and fireplace simultaneously for long periods of time. This can create serious backdrafting that prevents CO gas from exiting the home.
* Never install a boiler, furnace or water heater in an airtight enclosure.
* Look for the following signs that may indicate CO problems - streaks of soot around the service door of a gas appliance; rust spots on flue pipe, boilers, furnaces or water heaters; excessive moisture on basement windows, which may indicate poor ventilation; generally stale air throughout the house, another sign of poor ventilation.
* DO INSTALL A UL-APPROVED CO DETECTOR. The UL standard requires home CO detectors to sound a warning before CO levels reach over 100 parts per million (ppm) over 90 minutes, 200 ppm over 35 minutes or 400 ppm over 15 minutes. These warning should allow the average person to safely evacuate the premises. (CO levels over 200 ppm lasting for 90 minutes can cause headaches in healthy adults. At 300 ppm the healthy adult may experience drowsiness, at 400 ppm might collapse and 500 ppm exposure could result in brain damage or death.)
Approved CO detectors are now available for around $50 or less. They are similar to smoke detectors in both appearance and installation. The best place to install a CO detector is near bedrooms. Don't install one in the boiler or furnace room the garage or the kitchen, where it may go off in reaction to temporary elevated levels of CO.
Cheap CO-detection patches that sell for under $10 are not of much use. These devices are based on chemical reactions that change the color of a spot in the presence of elevated CO. They register many false positives and tell you nothing unless you are looking at the spot for a telltale change of color. What you need is an alarm that alerts you to danger as soon as it arises and wakes you up if you are asleep.
What do you do if the alarm sounds? Vacate the house quickly, opening doors and windows as you leave in order to provide ventilation. Then contact a local emergency service crew - usually the police or fire department - for advice. Depending on your community, they may have a CO measuring device on hand to take a reading inside your home in order to determine if it is safe to move back in.
Keep in mind that the act of ventilating your home may make it safe for immediate occupancy but won't fix whatever generated excess CO in the first place. As soon as possible you need a professional inspection of all possible CO sources. This should be someone equipped with CO measuring gear able to detect concentrations as small as 5-10 parts per million. The measurement test should be conducted over at least a 24-hour period.
It is possible for a CO alarm to be triggered by a single unusual incident that presents no lasting threat. However, if one ever goes off in your home, you won't rest easily until you take all the precautions possible to safeguard yourself and love ones