With temperatures dropping and cold weather settling in, people will turn to gas furnaces, space heaters and fireplaces for warmth. Not so fast, caution pulmonologists from Harris Health System, who recommend that everyone get those devices checked for carbon monoxide leaks.

Known as the silent killer, carbon monoxide is the gas byproduct of the incomplete combustion of fuel used in cars, gasoline engines, stoves, lanterns, burning charcoal or wood, gas ranges, fireplaces and heaters. The gas is colorless and odorless, but can be deadly.

"You can't see or smell carbon monoxide, but it can cause significant health issues and possibly kill you," says Dr. K. Guntupalli, chief, Pulmonary Critical Care and Sleep Section, Harris Health Ben Taub Hospital and professor, Baylor College of Medicine.

Carbon monoxide enters the bloodstream and robs the body of much-needed oxygen. While mild exposure can be easily treated, high or prolonged exposure to carbon monoxide can be deadly.

Exposure symptoms:

    Headache
    Dizziness
    Confusion
    Weakness
    Nausea or vomiting
    Chest pain

High exposure affects:

    Cardiovascular
    Central nervous system
    Lungs
    Brain

Prolonged exposure causes:

    Depression
    Confusion
    Memory loss
    Death

Annually, according the U.S. Centers for Disease Control and Prevention, about 400 people nationwide die and 4,000 are hospitalized for carbon monoxide poisoning. About 20,000 people get sick enough to visit an emergency center. The most at risk are children, the elderly and those with chronic problems like heart disease, anemia and respiratory ailments.

If carbon monoxide poisoning is suspected, it's recommended that one leave the confined area and go outside for fresh air. Oxygen usually clears up most symptoms. For more severe cases, medical staff can administer concentrated oxygen treatments using face masks or pressurized hyperbaric chambers.

Dr. Nick Hanania, director, Asthma Clinical Research Center, Harris Health Ben Taub Hospital and associate professor, Baylor College of Medicine, cautions to never use gas-powered generators or charcoal grills indoors or use gas stove tops and ovens to stay warm. He recommends hiring a professional to inspect furnaces and fireplaces annually before using them. Another recommendation is installing a carbon monoxide detector, similar to a smoke detector.

"You could be creating carbon monoxide and not realize it until it's too late," he says. "The dangers of carbon monoxide are too great to ignore."

To confirm a case of carbon monoxide poisoning requires a blood test. However, Hanania suggests tracking any unexplained symptoms of headaches, nausea, vomiting or weakness while in a setting that seem to go away when out of that location.

"If several people in your house are having similar problems, then you should consider that it could be carbon monoxide poisoning and seek immediate medical attention," he says.

For more information on carbon monoxide poisoning, visit the U.S. Centers for Disease Control and Prevention at http://www.cdc.gov/co/faqs.htm