Final answer:
Technicians must evacuate an appliance containing 10 pounds of CFC-500 to 4 inches of mercury vacuum before disposal if using pre-1993 equipment, according to EPA regulations.
Step-by-step explanation:
When using recovery and recycling equipment manufactured before November 15, 1993, technicians must evacuate an appliance containing 10 pounds of CFC-500 to a level of 4 inches of mercury vacuum before disposing of the appliance. This requirement is based on the regulations set forth by the United States Environmental Protection Agency (EPA) to properly manage and contain refrigerants, which are substances or mixtures, usually fluids, used in refrigerators and air conditioners that can have detrimental effects on the ozone layer if released into the atmosphere.