You cannot see or smell carbon monoxide, but undetected it can kill you within minutes. The colorless, odorless gas is produced by the burning of gas, oil, kerosene, wood and charcoal. The correct use of properly working appliances does not generally produce harmless levels of carbon monoxide. However, malfunctioning or improperly used fuel-burning appliances, as well as idling cars, result in hundreds of accidental deaths each year, according to the Environmental Protection Agency (EPA).

Common sources include unvented kerosene and gas space heaters; leaking chimneys and furnaces; back-drafting from furnaces, gas water heaters, wood stoves, and fireplaces; gas stoves; exhaust from automobiles; and environmental tobacco smoke.

Since it is common to be exposed to carbon monoxide, it's smart to know the symptoms of carbon monoxide poisoning. Low levels of exposure can cause shortness of breath, nausea and headaches, and fatigue. Higher levels can produce severe headaches, dizziness, mental confusion, nausea and fainting. Substantial exposure to high concentrations can even be fatal.

To reduce your exposure:

• Keep gas appliances properly adjusted.
• Use vented space heaters, proper fuel in kerosene space heaters, and an exhaust fan vented to the outdoors over gas stoves. Don't sleep in rooms with unvented heaters in use.
• Open fireplace flues.
• Don't use a charcoal grill indoors, even in a fireplace.
• Don't use a gas stove to heat your house, even briefly.
• Don't use gas-powered engines in enclosed spaces.
• Have a trained professional inspect your fuel-burning appliances and central heating system annually and repair leaks.
• Don't idle the car inside the garage-fumes can build up quickly.
• If you use a carbon monoxide detector, don't consider it a substitute for the above precautions. Carbon monoxide detectors vary widely in quality and are not always reliable.

If you think you have been exposed to carbon monoxide:

• Get fresh air immediately.
  
• Go to an emergency department and alert the staff of your possible exposure. A blood test can often confirm carbon monoxide poisoning.

In cases of severe carbon monoxide poisoning, patients in the Cincinnati area are sent to The Center for Hyperbaric Medicine at The University Hospital, the only facility of its kind in Greater Cincinnati. With Hyperbaric treatments, a patient breaths in 100 percent oxygen. Emergency care is available from specially trained Hyperbaric Medicine physicians 24 hours per day, seven days a week.