What is the primary hazard associated with high CO2 levels during combustion?

The primary hazard associated with high CO2 levels during combustion is the risk of asphyxiation. Carbon dioxide is produced during the combustion of carbon-containing fuels, and high levels can displace oxygen in the air. When the concentration of CO2 exceeds safe levels, it can lead to a lack of sufficient oxygen for breathing, resulting in suffocation and potentially life-threatening situations.

While decreased efficiency can be a consequence of other combustion-related issues, it does not directly capture the immediate health risk posed by elevated CO2 levels. The presence of high CO2 indicates incomplete combustion, which can affect efficiency but is not the most critical concern when it comes to human safety. In contrast, the asphyxiation risk arises quickly and dangerously, making understanding and mitigating high CO2 levels vital in combustion environments.