Carbon monoxide (CO) is a colorless, odorless, and tasteless gas, and undetectable by human senses. It is a byproduct of combustion from various everyday appliances. It forms when fuels burn without enough oxygen, a process called incomplete combustion.
How Fire Produces Carbon Monoxide
Carbon monoxide forms during incomplete combustion, which occurs when there is an insufficient supply of oxygen for a fuel to burn completely. In complete combustion, fuels like wood or natural gas react with ample oxygen to produce carbon dioxide (CO2) and water. However, when oxygen is limited, the carbon in the fuel cannot fully oxidize, leading to the formation of carbon monoxide instead of carbon dioxide.
Fires in enclosed or poorly ventilated spaces often lead to incomplete combustion due to restricted airflow. This can happen with any carbon-containing fuel, including gasoline, natural gas, propane, charcoal, wood, or kerosene. The presence of a yellow or reddish flame, as opposed to a blue one, can sometimes indicate incomplete combustion is occurring.
Common Sources of Carbon Monoxide
Many household items and activities can produce carbon monoxide if not properly maintained or ventilated. Malfunctioning or improperly installed fuel-burning appliances such as furnaces, water heaters, gas stoves, and clothes dryers are frequent sources. Fireplaces and wood-burning stoves can also generate CO, especially if their flues are blocked or not properly vented. Other sources include charcoal grills used indoors, portable generators, and vehicle exhaust, particularly when cars are left running in attached garages. This risk is heightened in energy-efficient homes that may not allow enough fresh air to dilute CO output.
The Dangers of Carbon Monoxide
Carbon monoxide is dangerous because it interferes with the body’s ability to transport and utilize oxygen. When inhaled, CO enters the bloodstream and binds with hemoglobin, the protein in red blood cells responsible for carrying oxygen. Carbon monoxide has a much stronger affinity for hemoglobin than oxygen, binding about 200 to 250 times more readily. This forms carboxyhemoglobin, which prevents red blood cells from carrying oxygen to vital organs and tissues.
Symptoms of CO poisoning can range from mild, such as headache, dizziness, nausea, and weakness, to severe. Higher levels of exposure can lead to confusion, chest pain, loss of muscle coordination, seizures, unconsciousness, and even death. Because CO is undetectable by human senses, individuals can be overcome without realizing the danger.
Protecting Your Home and Family
Preventing carbon monoxide poisoning involves a combination of awareness and practical safety measures. Installing carbon monoxide detectors is a primary defense, with placement recommended outside each separate sleeping area and on every level of the home. These alarms should be tested monthly using their test button, and their batteries should be replaced annually.
Ensuring proper ventilation for all fuel-burning appliances is also important. This includes having heating systems, water heaters, and other appliances professionally inspected and serviced by qualified technicians every year. Never use outdoor equipment like charcoal grills or portable generators inside a home, garage, or any enclosed space, and ensure vehicle exhaust pipes are not blocked.