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.
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. You may also want to install CO detectors inside your home to provide early warning of accumulating carbon monoxide. However, a CO detector is no substitute for safe use and maintenance of heating and cooking equipment. Household carbon monoxide detectors measure how much CO has accumulated.