Part of the U.S. Clean Air Act of 1990. It is a federal law that since 1992 has required technicians working for pay to be certified to recover and recycle refrigerant. It restricted purchase of R-12 to certified technicians. As of 1/1/2018, purchase of containers of refrigerants of two pounds or more is restricted to certified technicians. You must display a Section 609 card in order to purchase containers of refrigerant in quantities of two pounds or more.