Thomas H. Greiner, Extension Agricultural Engineer Department of Agricultural and Biosystems Engineering, Iowa State University.
Incomplete combustion uses fuel inefficiently and the carbon monoxide produced is a health hazard.
Most burners produce much less, with between 0 and 50 ppm being typical. During incomplete combustion, carbon monoxide concentrations may reach levels above 7,000 ppm. Even a small amount of spillage into occupied structures from appliances producing large amounts of CO is a health risk and can be a threat to life. Insufficient time to burn. Cooling of the flame temperature before combustion is complete.