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Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is toxic to humans and animals. CO gas is produced during the combustion of flammable materials such as the burning of wood, gasoline, or natural gas in fireplaces, cars, and engines, and gas appliances. Combustion appliances are designed to emit very little CO gas into the structure they are in, but if the combustion process is not operating efficiently or if the exhaust flue is blocked then significant amounts of carbon monoxide can accumulate in a structure. CO gas is measured in parts per million (ppm) and 5ppm or lower is considered normal in a home, 15ppm can be detected in the vicinity of a properly operating stove. Combustion appliances require a specific amount of combustion air in order to prevent the buildup of CO gas. If an appliance has an inadequate amount of oxygen then the combustion process does not work efficiently and large amounts of CO gas can be produced. For this reason, gas furnaces, water heaters, and dryers must have proper ventilation to provide enough combustion air to prevent excess CO gas from being produced. 

Dangers of carbon monoxide public service announcement

Carbon monoxide is not possible to see, smell, or taste, so it is very important that all homes have CO detectors within 15 feet of all bedroom doors, and near fireplaces or garage doors into the home. Carbon monoxide is toxic and can cause headaches and nausea at low concentrations, and memory loss, brain damage, or death at higher concentrations.


We strongly recommend that at least one CO detector be installed on each level with bedrooms, fireplaces, or access to the garage, as well as regular testing and replacement of the detectors as the sensor wears out over time and may not provide sufficient protection if the detector is too old. Never use a generator or barbecue grill inside a structure even if the power is out. Generators should be used outside of the house away from any open window or door. Do not run any engines inside the garage even with the exterior door open since buildings usually have lower air pressure inside than outside which pulls air into the building. Ensure that combustion appliances are properly adjusted, in good condition, have sufficient combustion air available and that the exhaust is never obstructed.

Due to the dangerous nature of CO and the ease with which it can be tested, Timberline Ridge Home Inspections performs FREE carbon monoxide testing on the properties we inspect. The maximum reading will be listed in the inspection report, and we will attempt to determine the source of the CO in the property. For more information regarding carbon monoxide and the dangers it poses, talk to your doctor or visit

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