Choice is importing the hydrofluorocarbon (“HFC”) refrigerant blend “R-421A” from China. R-421A is a refrigerant gas which is typically shipped as a compressed gas in ISO pressure tanks or smaller compressed gas cylinders. Chemically, R-421A is a blend, comprised of 42% by weight 1,1,1,2-tetrafluoroethane (CAS # 811-97-2), 58% by weight pentafluoroethane (CAS # 354-33-6, and a proprietary lubricant. You state that R-421A is a proprietary formulation, “invented by Choice Refrigerants as a popular refrigerant used in residential, commercial and industrial air conditioning and refrigeration equipment in the U.S. As a substitute for the older refrigerant R-22, which has been phased out of production by the U.S. Environmental Protection Agency.” The product is sold under the “Choice® R-421A” trademark.
[1] Please importantly note that only the relevant portion of the related is displayed above. You may refer to the said customs ruling for the entire ruling explanation.
[1]. https://rulings.cbp.gov/ruling/N309855