Carbon monoxide reacts with oxygen gas to produce carbon dioxide according to the following equation:

`2 CO + O_2 -> 2 CO_2` 

At room temperature this reaction must be catalyzed.

Carbon monoxide is a colorless, odorless poisonous gas. It's produced by the incomplete combustion of hydrocarbons. While combustion usually produces carbon dioxide, limited oxygen will result in carbon monoxide production. This can happen when gas or wood-burning appliances are improperly ventilated or when material combusts in an enclosed space.

Carbon monoxide poses a danger to humans and other animals because, when inhaled, it prevents oxygen uptake by the lungs. Inhaled oxygen normally bonds to hemoglobin molecules in blood as it passes through the lungs. Carbon monoxide bonds to the same sites on the hemoglobin molecule as oxygen and has a much higher tendency to bond to the hemoglobin. Prolonged inhalation of carbon monoxide can be deadly. Carbon monoxide detectors can be installed in homes with appliances or heating systems that operate by combustion.