California Air Resources Board

SACRAMENTO - On average, 45 Californians die each year from carbon monoxide (CO) poisoning and many more experience flu-like symptoms from moderate CO exposure. More than half of the deaths are from malfunctioning or improperly vented combustion appliances such as gas and propane heaters, furnaces and hibachis. One third of the deaths are from accidental exposure to motor vehicle exhaust.

        "While maximum eight-hour outdoor carbon monoxide levels have been reduced since 1970, from 40 ppm to 14 ppm, we still hear of accidents that occur when people are exposed to lethal levels of indoor carbon monoxide while using poorly vented or leaking stoves, fireplaces and furnaces," said Air Resources Board (ARB) Chairman John Dunlap.

        Carbon monoxide is a colorless, odorless gas that results from burning fuels. At sub-lethal levels, CO can cause headaches, nausea or heart pain. The most susceptible victims include infants, small children, the elderly and heart and respiratory patients. CO poisoning cases are under-diagnosed and often go unrecognized by the victims and their doctors.

        The compound triggers responses in humans by displacing oxygen in red blood cells and depriving heart and brain tissue of enough oxygen to function properly. Extended exposure to high carbon monoxide levels can result in permanent heart or brain damage and even death.

        ARB data show that outdoor carbon monoxide levels rise throughout California between November and March because the compound tends to disperse more slowly in cool outdoor temperatures and because of the greater use of home heating equipment that may leak CO. Outdoor levels of CO high enough to trigger health complaints in sensitive people have been measured in covered garages and at busy intersections.

        The good news is that CO poisoning can be prevented by proper use, maintenance and venting of any appliances that produce a flame. Unvented appliances, such as kerosene and propane heaters, charcoal grills and unvented gas logs should never be used indoors. In fact, it is illegal for such appliances to be marketed for residential use in California. Care should also be taken not to operate car engines or other gasoline-powered equipment in enclosed or attached garages.

        People who heat with fireplaces and older wall or floor furnaces should be especially careful. Fireplaces and wood stoves should be checked for damage and cleaned each year before use. Contact your local utility company or a state-approved weatherization contractor immediately if you are concerned about the safety of your furnace. The ARB also encourages annual furnace check-ups by a qualified professional and the use of UL-approved carbon monoxide detectors that sound an alarm when dangerous CO levels are detected.

       Periodic inspection of your stove or fireplace is essential to ensure its continued safe and clean-burning operation. Be sure you carefully check and repair the following as needed:

• Chimney cap - can be plugged by debris which will reduce draft.
• Chimney - should be cleaned professionally at least once a year to remove creosote buildup.
• Catalytic combustor - holes can plug up; follow instructions to clean.
• Stovepipe - angles and bolts are particularly subject to corrosion.
• Gaskets - on airtight stove doors need replacement every few years.
• Seams - on stoves sealed with furnace cement may leak. Eventually the cement dries out, becomes brittle and may fall out.
• Firebrick - may be broken or missing.
• Grate - or stove bottom where the fire is built; this may crack or break.

        Free booklets, "Combustion Pollutants in Your Home" and the "Woodburning Handbook" are available from ARB by calling (916) 322-2990 or by writing to: Air Resources Board, Office of Communications, P.O. Box 2815, Sacramento, CA 95812.