Carbon monoxide (CO) is a colorless, odorless gas with no taste. Symptoms of exposure are similar to the flu - headache, breathlessness, fatigue, and nausea - but can eventually lead to unconsciousness. Sources of CO in homes are the incomplete combustion of fuels, and come from fuel-burning appliances and devices such as furnaces or boilers, water heaters, gas stoves and ovens, motor vehicles (as in attached garages), fireplaces (both gas and wood burning), clothes dryers, and tobacco smoke. As of 2011, California law (SB 183) requires that all residential properties have installed CO detection equipment.
Below is further information on sources of carbon monoxide in homes and how to avoid carbon monoxide exposure.