In the home, heating and cooking equipment are possible sources of carbon monoxide. Vehicles running in an attached garage could also produce dangerous levels of carbon monoxide. However, consumers can protect themselves against CO poisoning by maintaining, using, and venting heating and cooking equipment and by being cautious when using vehicles in attached garages. CO replaces oxygen in the bloodstream, eventually causing suffocation. Mild CO poisoning feels like the flu, but more serious poisoning leads to difficulty breathing and even death.
Higher concentrations are dangerous even for a short time.
Table 1 shows typical symptoms based on concentration and time of exposure. Carboxyhemoglobin levels do not consider the length of exposure. As more and more carbon monoxide accumulates in the blood, the percentage of COHb gets higher and higher and people get sicker and sicker. Table 2 links symptoms of CO poisoning with percent of carboxyhemoglobin saturation. Deaths from unintentional carbon monoxide poisoning about 700 in 1993, according to the National Safety Council are fairly rare.