Who must be certified in refrigerant recovery?

The certification for refrigerant recovery is required specifically for technicians who are performing service on sealed systems. This is essential because refrigerants can be harmful to the environment and pose safety risks if not handled properly. Technicians must be knowledgeable about the safe methods of recovering and handling refrigerants, as well as the legal requirements governing the handling of these substances.

Sealed systems, found in various appliances such as refrigerators and air conditioners, contain refrigerant that must be carefully managed to prevent leakage into the atmosphere, which can contribute to ozone depletion and climate change. Therefore, the EPA mandates that technicians must demonstrate a level of competence and understanding through certification to ensure that they can safely and effectively recover refrigerants from these sealed systems.

The other options do not reflect the necessity of certification for refrigerant recovery. While all appliance users may interact with systems that use refrigerants, they are not responsible for recovery processes. Only certified engineers do not encompass the full scope of the technicians who work in the field; rather, it's specifically those who perform sealed system services who must be certified. Hence, the accurate understanding of the requirement points to technicians engaged in this particular type of work.