Phosgene gas can be produced in a refrigeration system by which action?

Phosgene gas is a highly toxic compound that can be generated when refrigerants, particularly those containing chlorine, are subjected to high temperatures, such as those produced by the heat of welding. When soldering or brazing on a refrigeration system, the intense heat can cause certain refrigerants in the system to decompose, potentially resulting in the formation of phosgene gas.

This situation underscores the importance of proper safety protocols when performing repairs or maintenance on refrigeration systems, including ensuring that the system is properly evacuated and that appropriate ventilation and safety measures are in place. Understanding the conditions under which phosgene can form is crucial for maintaining safety and preventing hazardous situations in the field.