What chemicals are most commonly used as fentanyl precursors and how are they disguised for export from China?
Executive summary
Chinese firms and intermediaries have long supplied chemical inputs used to make fentanyl; U.S. authorities and others identify a core set of “precursors” and related intermediates that traffickers favour, and Beijing announced new export licensing for 13 chemicals in November 2025 (see reporting on the controls) [1] [2]. Enforcement actions and seizures continue: Canada’s CBSA intercepted 4,300 litres of mixed precursor chemicals from China in 2025, including 500 L of propionyl chloride, a named fentanyl precursor [3].
1. What chemicals are repeatedly identified as fentanyl precursors
Public U.S. law-enforcement reporting and congressional briefs name a set of chemicals used as inputs or “precursors” in fentanyl synthesis; agencies cite both internationally controlled substances and a broader group of legally-exportable industrial chemicals sold online by China-based firms [4] [5]. Recent diplomatic and enforcement announcements highlight 13 chemicals that China agreed to place under export licensing in late 2025, and other U.S. indictments and seizures have repeatedly named specific reagents such as propionyl chloride and NPP/ANPP as high‑value inputs for illicit manufacture [1] [3] [6].
2. How traffickers and suppliers adapt: substitute and “designer” precursors
Law-enforcement analysis and independent commentators say traffickers shift to alternate synthetic routes and substitute or “designer” precursors when controls bite. Reporting warns that regulatory lists can be circumvented by using chemically similar, uncontrolled intermediates — a pattern noted before and after China’s prior scheduling moves — which creates a persistent cat‑and‑mouse problem for regulators [6] [7].
3. Tactics used to disguise shipments from China
Indictments and agency statements describe commercial concealment tactics: firms sell and ship precursors through ordinary export channels, advertise online to buyers worldwide, and package bulk quantities in typical industrial drums and jugs that resemble legitimate chemical commerce. One indictment notes sales in 25‑kilogram fiber drums, and the Canada seizure involved clear jugs and blue drums in marine containers bound for Calgary, underscoring how standard packaging facilitates hiding illicit intent amid legitimate trade [8] [3] [4].
4. Commercial and state incentives that complicate enforcement
U.S. government reporting and a mandatory congressional report allege that some Chinese firms benefit from subsidies, tax rebates and official patronage, and that state‑linked entities — including a company tied to a prison — have featured in precursor export networks. That financial and institutional environment can lower the cost of producing and exporting precursors and blunt market incentives to police illicit sales [9].
5. Recent bilateral steps and their limits
U.S. officials, including the FBI director, have announced agreements with China to tighten control over 13 precursor chemicals and certain subsidiaries, and China’s commerce ministry said licenses will be required for exports to North America [2] [1]. Independent analysts caution those moves may not catch “designer” precursors or novel synthetic routes; insightCrime and other reporting explicitly say earlier agreements left gaps for non‑listed chemicals [7].
6. Enforcement evidence: seizures, indictments, and sanctions
U.S. and allied enforcement actions have been concrete: multiple indictments of China‑based companies and executives allege long‑running sales of precursors and finished fentanyl, and Treasury sanctions and criminal cases have targeted firms accused of supplying precursors and related materials. The U.S. Treasury described China‑based chemical manufacturers as the primary source of precursor chemicals entering the U.S., and Canada’s CBSA publicised a seizure linking shipments from China to billions of potential pill doses [10] [8] [3].
7. Competing narratives and political framing
Chinese officials have defended China’s record and said they tightened controls, while some U.S. political actors frame Beijing as enabling the U.S. overdose crisis through weak oversight or subsidies; congressional and law‑enforcement reports assert both ongoing supplier responsibility and the need for deeper information‑sharing and know‑your‑customer standards [2] [4] [5]. Independent analysts argue policy steps so far may be incomplete and that traffickers swiftly adapt [7] [6].
8. Limits of the available reporting
Available sources list broad categories of chemicals, cite specific examples like propionyl chloride and NPP/ANPP, and document tactics and policy steps, but they do not publish an exhaustive roster of every precursor or the full tradecraft of concealment in minute operational detail; those operational specifics are largely found in indictments and selective enforcement reports referenced above [3] [8] [1]. Sources do not provide a complete chemical table here, and they warn that controls on a set of chemicals do not eliminate the ability to synthesize fentanyl using alternate precursors [7] [6].
Conclusion — what to watch next
Monitor enforcement filings, seizure reports and the formal Chinese export‑control lists for the 13 named chemicals and any follow‑on designations; those documents will show whether licensing measures close the gaps that analysts say traffickers exploit, or whether substitutions and “designer” precursors continue to sustain illicit fentanyl manufacture [1] [7] [6].