At high temperatures, R-12 and R-22 can decompose to form which harmful gas?

The correct answer is phosgene gas. At high temperatures, refrigerants like R-12 (dichlorodifluoromethane) and R-22 (chlorodifluoromethane) have the potential to decompose into phosgene, which is a highly toxic gas. This decomposition can happen during events such as fires or other extreme conditions, where the temperatures exceed the normal operating range of these refrigerants.

Phosgene is particularly hazardous because it can cause serious respiratory distress and has a delayed onset of symptoms. It was historically used as a chemical warfare agent during World War I, which adds to the severity of its potential health impacts.

Understanding the decomposition products of refrigerants is crucial for safety protocols in handling, storing, and disposing of refrigerants. Awareness of these risks helps technicians in the HVAC field take proper precautions to prevent exposure to harmful substances during their work with refrigerants.