Proposed rule · 2025-09983

Designation of Propionyl Chloride as a List I Chemical

The Drug Enforcement Administration is proposing the control of propionyl chloride as a list I chemical under the Controlled Substances Act (CSA). The Drug Enforcement Administration finds that propionyl chloride is used in the illicit manufacture of the controlled substances fentanyl, fentanyl analogues and fentanyl-related substances, and is important to the manufacture of these substances. In the respective synthetic pathways in which it is used to manufacture those substances, it is a replacement for propionic anhydride, which is currently a list I chemical. If finalized, the proposed rule would subject handlers of propionyl chloride to the chemical regulatory provisions of the CSA and its implementing regulations. This proposed rulemaking does not establish a threshold for domestic and international transactions of propionyl chloride. As such, all transactions of propionyl chloride, regardless of size, shall be regulated. In addition, chemical mixtures containing propionyl chloride are not exempt from regulatory requirements at any concentration. Therefore, all transactions of chemical mixtures containing any quantity of propionyl chloride shall be regulated pursuant to the CSA. Although no automatic exemption is available, manufacturers may submit an application for exemption.