Facts About Carbon Monoxide

Facts About Carbon Monoxide

Carbon monoxide, with the chemical formula CO, is a colorless, odorless and tasteless, yet highly toxic gas. Its molecules consist of one carbon atom and one oxygen atom.

New Colorado Law Requires Carbon Monoxide Detectors

Carbon monoxide detectors will be required for all open permits on single and multi-family dwellings beginning July 1, 2009 with the enactment of the Lofgren and Johnson Families Carbon Monoxide Safety Act (CRS 38-45).

The Lofgren and Johnson Families Carbon Monoxide Safety Act states that approved carbon monoxide detectors need to be located within fifteen feet of the entrance to all rooms used lawfully for sleeping purposes. In addition, if the permit is for a multi-family rental unit, a carbon monoxide detector needs to be located within twenty-five feet of any fuel-fired heater, fuel-fired appliance, fireplace or garage.


Carbon monoxide poisoning is the most common type of fatal poisoning in many countries. Carbon monoxide is colorless and odorless, but extremely toxic: it combines with hemoglobin in the blood to produce carboxyhemoglobin (HbCO), which is ineffective for delivering oxygen to the body tissues (a condition known as anoxemia). Concentrations as low as 667 ppm can cause up to 50% of the body's hemoglobin to convert to HbCO. In the United States, OSHA limits long-term workplace exposure levels to 50 ppm. The most common symptoms of CO poisoning can resemble the flu, including headache, nausea and vomiting, dizziness, lethargy and a feeling of weakness. Infants may be irritable and feed poorly. Neurological signs include confusion, disorientation, visual disturbance, syncope and seizures.

Urban pollution

Carbon monoxide is a major atmospheric pollutant in urban areas, chiefly from exhaust of internal combustion engines (including vehicles, portable and back-up generators, lawn mowers, power washers, etc.), but also from improper burning of various other fuels (including wood, coal, charcoal, oil, kerosene, propane, natural gas, and trash). Along with aldehydes, it reacts photochemically to produce peroxy radicals. Peroxy radicals react with nitrogen oxide to increase the ratio of NO2 to NO, which reduces the quantity of NO that is available to react with ozone.

Indoor pollution

In closed environments, the concentration of carbon monoxide can easily rise to lethal levels. On average, about 170 people in the United States die every year from CO produced by non-automotive consumer products. These products include malfunctioning fuel-burning appliances such as furnaces, ranges, water heaters and room heaters; engine-powered equipment such as portable generators; fireplaces; and charcoal that is burned in homes and other enclosed areas. In 2005 alone, CPSC staff is aware of at least 94 generator-related CO poisoning deaths. Forty-seven of these deaths were known to have occurred during power outages due to severe weather, including Hurricane Katrina. Still others die from CO produced by non-consumer products, such as cars left running in attached garages. The Centers for Disease Control and Prevention estimates that several thousand people go to hospital emergency rooms every year to be treated for CO poisoning. Carbon monoxide is also a constituent of tobacco smoke.

For more information about Carbon Monoxide and Indoor Air Quality please go to the EPA.