California Air Resources Board

SACRAMENTO – On average, 45 Californians die each year from accidental carbon monoxide (CO) poisoning and many more experience flu-like symptoms from moderate CO exposure according to Air Resources Board (ARB) data.

        "Carbon monoxide is a colorless, odorless gas that results from burning fuel.  Each winter we hear of tragic accidents that occur when people are exposed to lethal levels of indoor CO from improperly vented or leaking furnaces, ovens and fireplaces.  At below-lethal levels, CO can still cause headaches, nausea or heart pain.  Preventive steps taken now can avert tragedy later," said ARB Chairman Barbara Riordan.

        Carbon monoxide causes toxic effects in humans by replacing oxygen in red blood cells and depriving heart and brain tissue of enough oxygen to function properly.  Extended exposure to high CO levels can result in permanent heart or brain damage and even death.  Those most susceptible include infants, small children, the elderly and heart and respiratory patients.

         More than half of CO poisoning deaths are from malfunctioning or improperly vented combustion appliances such as gas furnaces, gas and propane space heaters and small barbeques.  Another third of the deaths result from accidental exposure to CO from vehicles running in closed garages.
 
        CO poisoning can be prevented by proper use, maintenance and venting of any appliances that produce a flame.  Because of the danger from poor ventilation, kerosene or propane space heaters, charcoal grills and unvented gas logs cannot be used legally indoors in California.

         People who heat with propane appliances, older wall or floor gas furnaces and fireplaces should be especially careful.  Fireplaces and wood stoves should be checked for damage and cleaned each year before use.  Contact your county weatherization contractor immediately if you are concerned about the safety of your gas furnace or oven.  The ARB also encourages annual furnace check-ups by a qualified professional and the use of UL-approved CO detectors that sound an alarm when dangerous carbon monoxide levels are detected.  Some detectors also have warning signals or digital readouts to indicate lower levels of CO.

         ARB data show that outdoor CO levels rise throughout California between November and March because of stagnant weather conditions.  Outdoor levels of CO high enough to trigger health complaints in sensitive people have been measured in covered garages and at busy intersections.  Care should also be taken not to operate car engines or other gasoline-powered equipment in enclosed or attached garages.  Cars should be tuned and muffler systems checked regularly for exhaust leaks.

         A free booklet, "Combustion Pollutants in Your Home" and "Woodburning Handbook," is available from ARB by calling (916) 322-8282, by clicking here, or by writing to:  Air Resources Board, Indoor Air Quality Program, Research Division, P.O. Box 2815, Sacramento, CA 95812.