Carbon Monoxide Detectors CO is a colourless, odourless gas. You can’t see, taste or smell it. CO is a common by-product of the burning of natural gas, gasoline and solid fuels (wood, pellets, etc.). Fireplaces that are properly installed, maintained and operated will produce little CO. However, if anything disrupts the venting process (such as a bird’s nest in a chimney) or restricts the oxygen to a gas burner, CO production can quickly rise. Gasoline engines produce CO, especially when a cold engine starts. CO can accumulate if you start and idle your vehicle or gas mower in the garage. CO can enter a home through connecting walls or doorways and quickly rise to dangerous levels. Doors leading from the garage to your home should be regularly checked to ensure they are properly sealed. Rooms with solid fuel-burning appliances must also have a CO detector. Some examples include a Furnace, a water heater, a fireplace and gas appliances. FIREPLACES 81