 Carbon monoxide poisoning occurs after too much inhalation of carbon monoxide ( CO ) . Carbon monoxide is a toxic gas , but , being colorless , odorless , tasteless , and initially non @-@ irritating , it is very difficult for people to detect . Carbon monoxide is a product of incomplete combustion of organic matter due to insufficient oxygen supply to enable complete oxidation to carbon dioxide ( CO2 ) . It is often produced in domestic or industrial settings by motor vehicles that run on gasoline , diesel , methane , or other carbon @-@ based fuels and from tools , gas heaters , and cooking equipment that are powered by carbon @-@ based fuels such as propane , butane and charcoal . Exposure at 100 ppm or greater can be dangerous to human health . 
