SACRAMENTO – The California Air Resources Board (ARB) today issued its annual winter months' carbon monoxide (CO) warning to Californians, especially the elderly, pregnant women and people with heart and respiratory aliments.

"This is the time of year to check your appliances for leaks or damage, before you use them in the coming cold months," said ARB Executive Officer, Catherine Witherspoon. "A sad tragedy can easily be avoided by observing simple maintenance practices. And most California utility companies will check them for free."

Each winter, tragic accidents occur when people are exposed to toxic levels of indoor CO from improperly vented or leaking furnaces, ovens and fireplaces. On average each year, 30-40 Californians die and many more experience flu-like symptoms from accidental CO poisoning. These are easily preventable tragedies. Burning fuel produces CO, and extended exposure can have a lethal effect on humans. Even below toxic levels, exposure to CO may cause headaches, nausea, fatigue or heart pain.

Carbon Monoxide adheres to red blood cells, blocking their ability to carry oxygen and thereby depriving the body's heart and brain of an adequate supply. The deprivation of oxygen leaves a person feeling sleepy and tired. If the person is not removed from the area and treated, suffocation may result. Those most susceptible include infants, young children, fetuses, the elderly and patients with pre-existing heart or respiratory conditions.

Because of concern over increased natural gas rates, many citizens are purchasing kerosene or propane space heaters this winter, or buying wood for use in long-ignored fireplaces and woodstoves. However, unvented combustion devices such as kerosene or propane space heaters cannot be sold for residential use in California because of the health risk they pose due to their high carbon monoxide emissions. Fireplaces and woodstoves that have not been used or inspected pose a similar risk, because of the potential for blocked flues, leakage and other factors.

More than half of CO poisoning deaths are from malfunctioning or improperly vented combustion appliances. Proper use and maintenance of any appliances that produce a flame such as gas furnaces, gas and propane space heaters and small barbecues, can prevent exposure to lethal levels of CO. Because of the danger from poor ventilation, California law prevents the use of kerosene or propane space heaters, charcoal grills and unvented gas logs indoors. Also gas ovens should not be used for heating the home. These combustion appliances also can emit large amounts of nitrogen dioxide, which can cause respiratory disease, especially in children.

The ARB also advises caution when operating cars or other internal combustion engines in enclosed spaces or attached garages. A third of CO poisoning deaths are the result of accidental exposure from vehicles, many due to running them in closed garages.

The ARB encourages annual furnace check-ups by a qualified professional and the use of Underwriters Laboratory (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, and this type of detector is recommended for homes with young children or elderly or sick occupants.

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. If you are concerned about the safety of your gas furnace or oven, contact your local utility provider or utility-certified heating contractor immediately and request a Combustion Appliance Safety Test.

ARB data show that outdoor CO levels rise throughout California between the months of November and March because of stagnant weather conditions. These outdoor levels of CO have been measured in covered garages and at busy intersections. Rising levels of outdoor CO may generate health complaints in sensitive people. Cars should be tuned and muffler systems checked regularly for exhaust leaks.

Free booklets, "Combustion Pollutants in Your Home" and "Woodburning Handbook"(1.4 MB PDF) are available from ARB by calling (916) 322-8282 or by writing to Air Resources Board, Indoor Air Quality Program, Research Division, P.O. Box 2815, Sacramento, CA 95812.