Until the World Customs Organization’s Harmonized Commodity Description and Coding System, or Harmonized System (HS) is revised in 2022, all HS codes for hydrofluorocarbons (HFCs) are contained in a single HS code which does not allow differentiation of the individual chemicals or of mixtures/blends. This document outlines a proactive interim approach, recommended by the World Customs Organization (WCO), to establish additional digits in the existing national HS codes to identify specific HFCs to facilitate monitoring of trade and enable a licencing system to function effectively.