SAN DIEGO -- Carbon monoxide is a deadly gas that is difficult to detect because it is odorless and invisible. As a result, it is known as the silent killer. According to the U.S. Consumer Product Safety Commission this poisonous gas kills nearly 300 people in their homes each year.

CO is produced by fuel-burning appliances and equipment in homes. If you have heating, cooking or power equipment that uses fuels such as oil, natural gas, coal, wood, propane, gasoline, etc., then your home is at risk for potential CO poisoning. Homes with attached garages are also at risk, because vehicles left running in the garage can cause CO to seep into the home.

CO poisoning can be prevented by proper care and use of household equipment. CO alarms can provide early detection if CO leaks or accumulation occurs. Both are important for your safety.

If you suspect CO poisoning in your home, call the appropriate responding agency, usually your local fire department or 911. Keep all emergency response numbers posted by every telephone. CO alarms are different from smoke alarms, and have different functions. CO alarms do not provide early warning of a fire. Smoke alarms do not provide early warning of CO exposure. Your home needs both CO and smoke alarm protection. Symptoms of CO poisoning are similar to symptoms of the flu, and can include headache, dizziness, nausea and shortness of breath. If you feel better after leaving home and then worse again when you return, it may be CO exposure causing the symptoms.

If your CO alarm sounds check to see if it is plugged in properly, or if battery-powered, check the battery to be sure the device is operating. If you suspect that CO is leaking in your home, follow these steps:

Open windows and doors to ventilate the rooms, or in severe cases of CO exposure, evacuate the home. Call to report that you suspect CO is accumulating. Usually the appropriate agency to call is the fire department or 911. Seek immediate medical treatment for anyone who has severe symptoms. Follow the advice of the responding agency before re-entering your home, and quickly obtain repairs as needed.

San Diego Gas & Electric is providing a free service for customers to detect carbon monoxide in their homes. Speak to a Customer Service Representative by calling their 24-hour Customer Service line at 1-800-411-SDGE (7343).