Companies such as BuyCalGas.com, ShopCross.com and DrillSpot.com sell commercial refrigerant. Because of the shipping restrictions that carriers such as DHL, Federal Express and UPS impose on transporting these tanks, most vendors refuse to accept returns.
Only Section 608- and Section 609-certified technicians are allowed to purchase refrigerant, per the regulations of the U.S. Environmental Protection Agency. This applies to all HCFC and CFC refrigerants that are sold in drums, cans or cylinders. This includes refrigerant blends that also have HCFCs in them. It doesn't cover any equipment or components that have refrigerant inside of them or any appliances that contain these refrigerants.
Section 608 certification permits technicians to purchase R-11, R-123 and R-22 refrigerants as well as containers of R-12 of more than 20 pounds. Employers of these technicians can also purchase these refrigerants if they can prove that they have at least one certified technician in their employ. Section 609 certification permits technicians to buy containers of R-12 of less than 20 pounds.
As of 2015, refrigerants that do not deplete ozone in the atmosphere, such as HFCs, do not have any sales restrictions. It is up to wholesalers to verify that the people they sell refrigerant to have the proper licensing.