Burning wood in fireplaces or wood stoves provides warmth and ambiance, but it also carries a significant risk: the production of carbon monoxide (CO). Wood, like any other fuel, produces this dangerous gas during combustion. This colorless, odorless gas can accumulate indoors, posing a serious threat.
How Wood Burning Produces Carbon Monoxide
Carbon monoxide forms when wood, or any carbon-containing fuel, burns without enough oxygen for complete combustion. In an ideal scenario, wood would burn completely to produce carbon dioxide and water, along with heat. However, when there is insufficient oxygen, the combustion process is incomplete, leading to the formation of carbon monoxide instead of carbon dioxide.
Several factors contribute to incomplete combustion. Burning wet or unseasoned wood is a common cause, as the moisture hinders efficient burning and reduces the fire’s temperature. Inadequate airflow to the fire, often due to closed dampers, insufficient air intake, or blocked vents, also starves the fire of oxygen, promoting CO formation. Additionally, smoldering fires, which burn at lower temperatures with limited oxygen, produce more carbon monoxide and harmful particulate matter. Creosote buildup and other chimney blockages can further restrict airflow and trap gases, including CO, indoors.
The Dangers of Carbon Monoxide Exposure
Carbon monoxide is often called the “silent killer” because it is a colorless, odorless, and tasteless gas, making it impossible to detect without specialized equipment. Once inhaled, carbon monoxide enters the bloodstream and binds to hemoglobin, the protein in red blood cells responsible for carrying oxygen. This strong binding forms carboxyhemoglobin (COHb), which effectively prevents red blood cells from transporting oxygen to the body’s tissues and vital organs.
Symptoms often mimic flu-like illness, which can delay diagnosis. Early signs include headache, dizziness, weakness, and nausea. As exposure continues, symptoms can worsen to include confusion, impaired judgment, chest pain, and shortness of breath. Severe poisoning can lead to loss of consciousness, seizures, permanent brain damage, cardiac arrest, and death.
Safe Wood Burning and Prevention
Preventing carbon monoxide buildup when burning wood requires careful attention to appliance operation and home safety measures. Ensuring proper ventilation means maintaining a clear and unobstructed chimney or flue system. Regular professional inspection and cleaning of wood-burning appliances and chimneys are necessary to remove creosote and other blockages that can impede exhaust flow. Adequate fresh air intake must also be available to support complete combustion and prevent backdrafting, where exhaust fumes are pulled back into the home.
Using only dry, seasoned wood is another important preventive step, as it burns more efficiently and produces fewer harmful emissions, including carbon monoxide. Avoid burning treated or painted wood, as these materials release toxic chemicals when combusted. The most effective way to detect carbon monoxide is by installing CO detectors throughout the home, especially near sleeping areas and on every level with fuel-burning appliances. These alarms provide an early warning of elevated CO levels, allowing occupants to take swift action. If a carbon monoxide detector alarms, immediately evacuate the building to fresh air and call emergency services, refraining from re-entering until professionals confirm it is safe.