What is the main gas that is hazardous when combustion appliances malfunction?

The main gas that poses a significant hazard when combustion appliances malfunction is carbon monoxide (CO). This colorless, odorless gas is a byproduct of incomplete combustion of carbon-containing fuels, such as natural gas, propane, oil, and wood. When appliances fail to operate properly, they can fail to burn fuel completely, leading to the production of carbon monoxide instead of the fully oxidized products, primarily carbon dioxide.

Exposure to carbon monoxide is dangerous because it binds to hemoglobin in the blood more effectively than oxygen, which reduces the amount of oxygen that can be transported throughout the body. This can lead to symptoms ranging from headaches and dizziness to severe complications, including unconsciousness or even death in high concentrations.

Understanding the risk of carbon monoxide is crucial for safety when using combustion appliances, emphasizing the need for proper ventilation and regular maintenance to prevent conditions that could lead to CO production.