Prevention, according to the Environmental Protection Agency:
DO have your fuel-burning appliances — including oil and gas furnaces, gas water heaters, gas ranges and ovens, gas dryers, gas or kerosene space heaters, fireplaces, and wood stoves — inspected by a trained professional at the beginning of every heating season. Make certain that the flues and chimneys are connected, in good condition, and not blocked.
DO read and follow all of the instructions that accompany any fuel-burning device. If you cannot avoid using an unvented gas or kerosene space heater, carefully follow the cautions that come with the device. Use the proper fuel and keep doors to the rest of the house open. Crack a window to ensure enough air for ventilation and proper fuel-burning.
DO call the Consumer Product Safety Commission (1-800-638-2772) at http://www.cpsc.gov for more information on how to reduce your risks from CO and other combustion gases and particles.
DON’T sleep in any room with an unvented gas or kerosene space heater.
CO detectors vary a lot. Some are pretty good, but not 100% reliable, others aren’t. They are not a substitute for the proper use and maintenance of your fuel-burning appliances.
Don’t let a CO detector lull you into a false sense of safety.