It’s time to test your smoke/fire and CO detectors! With winter coming on to cool much of the North West, it’s worthwhile to address a potential hazard that arises with increased use of fuel-burning appliances such as furnaces and water heaters: carbon monoxide. Carbon monoxide (CO) is an odorless, colorless gas produced by the combustion of fuels such as natural gas, oil, and propane in devices including furnaces, water heaters, and stoves. These items are normally designed to vent the CO to the outside, but harmful interior levels of CO can result from incomplete combustion of fuel, improper installation, or blockages, leaks or cracks in the venting systems. Very high levels of CO can lead to either incapacity or death, with victims sometimes never having been aware they were being poisoned.