What Are Precursor Chemicals
What are precursor chemicals?
Precursor chemicals (usually called "drug precursors") are chemicals that are needed to make illicit drugs but are also traded legally. Regulators therefore control their trade rather than banning them, so that legitimate supplies can't be diverted to illegal drug production. The European Commission describes them as "certain chemicals" required for producing illicit drugs such as heroin, cocaine and amphetamines. It notes that "preventing legally traded drug precursors from being diverted into the illegal circuit helps the fight against illicit drugs" (European Commission, drug precursors control).
How the EU regulates them (all from the same Commission page)
- Legislation: Regulation (EC) No 273/2004 covers trade in drug precursors within the EU. Regulation (EC) No 111/2005 covers trade between the EU and non-EU countries.
- Four categories:
- Category 1: "the most sensitive substances, from which illicit drugs can be produced most easily."
- Category 2: "less sensitive substances."
- Category 3: "bulk chemicals with various uses in manufacturing."
- Category 4: "medicinal products for human and veterinary use containing ephedrine or pseudoephedrine."
- Examples the Commission gives:
- Acetic anhydride, used to make heroin (1 to 1.5 litres per kilogram).
- Ephedrine and pseudoephedrine, used to make methamphetamine (1.5 kg gives 1 kg of methamphetamine).
- APAAN (alpha-phenylacetoacetonitrile), which has "no known legal use" but is frequently used to make illicit amphetamines.
A second example: Brazil Brazil's Federal Police controlled-chemicals list (Annex I to Portaria MJSP No 204/2022) puts drug precursors in List I. They are subject to control and inspection from 1 gram or 1 millilitre, at a concentration of 1% or more [1]. Some of the 29 entries:
- 1-phenyl-2-propanone [1]
- ANPP [2]
- APAAN [3]
- Ephedrine [4]
- Pseudoephedrine [5]
- Gamma-butyrolactone [6]
- Safrole [7]
- Lysergic acid [8]
The term is also used more broadly for controlled chemicals beyond drugs, for example the export-control lists for chemical-weapons precursors. I can look those up too.
Approach: I used the European Commission's drug precursors page and Brazil's Federal Police controlled-chemicals list. I couldn't open the EUR-Lex text of Regulation (EC) No 273/2004, so the EU points above are the Commission's summary, not the regulation's legal definitions.
How are drug precursors regulated in the EU and Poland?
In the EU, drug precursors fall under two directly applicable regulations: Regulation (EC) No 273/2004 for trade within the EU and Regulation (EC) No 111/2005 for trade with non-EU countries. Commission Delegated Regulation (EU) 2015/1011, Implementing Regulation (EU) 2015/1013 and, most recently, Delegated Regulation (EU) 2024/1331 sit alongside them. Poland applies these through the Act of 29 July 2005 on counteracting drug addiction. Two authorities share the work: the Chief Pharmaceutical Inspector (GIF) handles category 1, and the President of the Bureau for Chemical Substances (BSSC) registers operators for categories 2 and 3.
EU framework (European Commission, drug precursors control)
- Four categories:
- Category 1: the "most sensitive substances."
- Category 2: "less sensitive substances."
- Category 3: bulk chemicals with manufacturing uses.
- Category 4: medicinal products containing ephedrine or pseudoephedrine.
- Operator duties: The Commission's guidelines cover licensing and registration, customer declarations, reporting, and pre-notification of exports (run through the UN INCB's PEN-Online system). The Commission also keeps the EUDPD database and a list of "designer precursors."
Poland: who does what
- GIF (category 1):
- Grants permits to import and export category 1 precursors.
- Supervises their manufacture, processing, storage, trade and destruction (GIF competences).
- A wholesale trade permit for category 1 precursors is valid for three years. The application fee is 750 PLN (350 PLN to change a permit), and GIF decides within 30 days. You must name a qualified responsible person and document storage security (GIF wholesale permit).
- BSSC (categories 2 and 3): It grants registrations under Art. 3(6) of Regulation 273/2004 and Art. 7 of Regulation 111/2005, and keeps the national register under Art. 44(4) of the Act (consolidated text Dz.U. 2023 poz. 1939, as amended) (BSSC precursors page). The points below are all from that page:
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Trade within the EU: Users of subcategory 2A substances (acetic anhydride, red phosphorus) "muszą zostać zarejestrowani" (must be registered) before they acquire them, if the Annex II threshold is exceeded. Anyone placing 2A or 2B substances on the market needs registration.
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Exemptions: End-users of 2B substances need no registration. Nor do operators whose category 2 transactions stay below the thresholds over one year.
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Category 2 thresholds:
Subcategory Substance Threshold 2A Acetic anhydride 100 l 2A Red phosphorus 0.1 kg 2B Phenylacetic acid 1 kg 2B Anthranilic acid 1 kg 2B Piperidine 0.5 kg 2B Potassium permanganate 100 kg -
Trade with non-EU countries: Operators importing, exporting or brokering category 2 substances must be registered whatever the quantity; the thresholds apply only to trade within the EU.
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Category 3 exports need registration unless the previous calendar year's total stayed at or below these thresholds:
Substance Threshold Hydrochloric acid 100 kg Sulphuric acid 100 kg Toluene 50 kg Diethyl ether 20 kg Acetone 50 kg Methyl ethyl ketone 50 kg -
Applications: BSSC issues an administrative decision within 60 working days of a complete application. The procedure is set by Art. 9 of Regulation 2015/1013, and the content of the application by Art. 3 of Regulation 2015/1011. The stamp duty is 10 PLN.
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How to submit: Since 1 January 2026, apply by e-Doręczenia (electronic delivery) or by post. ePUAP is no longer a legally effective channel.
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Changes: Adding a substance, starting a new operation or moving premises requires a new registration. The old one lapses when the new one takes effect.
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- Suspicious transactions and penalties: Under Art. 8 of Regulation 273/2004, operators must report suspicious orders to the State District Sanitary Inspector or law enforcement. Illegal trade and record-keeping breaches carry criminal liability under Arts. 61, 66, 67, 69 and 70 of the Act (BSSC operator handbook, pp. 4-5).
Polish registers right now
- Under Regulation 273/2004 (state as of 23.09.2026): 280 entries. 191 are marked valid, 87 invalid and 2 suspended. Potassium permanganate (207 entries) and acetic anhydride (116) are the most common substances. Examples:
- Under Regulation 111/2005 (state as of 02.07.2026): 47 entries, 43 marked valid. Examples:
Approach: I searched BSSC's precursor operator registers and read the official BSSC, GIF and European Commission pages. EUR-Lex would not open, so I couldn't quote the legal text of Regulation 273/2004 itself (EUR-Lex entry). The EU-level points above therefore come from the Commission's summary and the Polish authorities' pages.
Sources:
What rules apply in the UK and US?
The UK and the US both control drug precursors as legally traded chemicals, but the systems are built differently. Great Britain still uses the EU precursor regulations that the UK kept after Brexit (Regulations 273/2004 and 111/2005), as amended by UK law, with the same four categories. The Home Office issues Category 1 licences and Category 2/3 registrations. Northern Ireland still applies the EU regulations directly. The US controls "listed chemicals" under the Controlled Substances Act. The DEA's rules (21 CFR Parts 1309, 1310 and 1313) set out 42 List I and 11 List II chemicals, with registration, record, reporting and import/export notification duties.
United Kingdom
Legislation (Home Office, Precursor chemical licensing, updated 10 June 2026)
- EU texts kept in UK law:
- Regulation (EC) No 273/2004 (domestic trade) and Council Regulation (EC) No 111/2005 (international trade). Both were amended by the Law Enforcement and Security (Amendment) (EU Exit) Regulations 2019 and the Controlled Drugs (Drug Precursors) (Amendment and Revocation) Regulations 2026.
- Delegated Regulation (EU) 2015/1011 and Implementing Regulation (EU) 2015/1013.
- UK regulations: the Controlled Drugs (Drug Precursors) (Intra-Community Trade) and (Community External Trade) Regulations 2008. A 2010 set of regulations sets the fees.
- Northern Ireland: the guidance states "NI continues to apply European Union regulations, while GB does not." Trade between GB and NI needs licences, but no fee is charged.
- Categories:
- Category 1: most sensitive.
- Category 2: less sensitive substances and pre-precursors.
- Category 3: bulk chemicals.
- Category 4: medicines containing ephedrine or pseudoephedrine.
2026 changes (Circular 003/2026)
- From 29 June 2026, 11 substances joined Category 1 in GB, including norfentanyl, 4-AP, 1-boc-4-AP, 4-piperidone, 1-boc-4-piperidone and the PMK/BMK glycidic acid ester groups. Red phosphorus joined Category 2A.
- From 1 July 2026, an Order amending Schedule 2 to the Criminal Justice (International Co-operation) Act 1990 makes offences UK-wide for 16 more substances, with a maximum of two years' imprisonment.
- The circular gives no transition period.
Domestic licensing and registration (Drugs and Firearms Licensing Unit, DFLU)
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Who needs it: anyone who possesses, manufactures, produces or supplies these chemicals.
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What you must provide: a responsible officer, a guarantor and DBS checks.
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Site visits and timing:
- First Category 1 licences, new sites and upgrades all get a licensing visit.
- Allow up to 16 weeks where a visit is needed, or 8 to 10 weeks where it isn't.
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Ongoing duties:
- Get end-user declarations for Category 1, and for Category 2 "depending on the level of trade involved."
- Document, record and label consignments, and file annual returns.
- "Notify the National Crime Agency immediately" of suspected diversion.
- Report thefts and losses (guidance).
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Fees (licence fees, updated 22 April 2024):
Item Fee Category 1 licence, new £3,655 Category 1 renewal £326 without a visit, £1,371 with one Category 2 or 3 registration, new £435 Category 2 or 3 renewal £109 without a visit, £1,153 with one Import or export licence, per consignment £24
Import and export (wallchart, updated 30 September 2026)
| Category | Imports | Exports |
|---|---|---|
| 1 | Consignment licence, all countries | Consignment licence plus pre-export notification (PEN), all countries |
| 2A (acetic anhydride, red phosphorus) | No authorisation | Licence plus PEN, all countries |
| 2B | No authorisation | Licence plus PEN. Exceptions: anthranilic acid to China, Indonesia, South Africa and Thailand; piperidine to the USA |
| 3 | No authorisation | Licence only for listed countries. For HCl and H₂SO₄ these are Bolivia, Chile, Colombia, Ecuador, Peru, Russia, Turkey and Venezuela |
| 4 | No authorisation | Licence plus PEN, all countries |
- You need a valid domestic licence before you can get an import or export licence.
- Import licences last 3 months. Export licences last 2 months, or until the importing country's permit expires if that is sooner.
- Licences cannot be issued retrospectively.
- PEN adds up to 17 working days on top of the 10-day processing time.
United States
Listed chemicals (21 CFR 1310.02, eCFR, current to 2 November 2026)
- List I (42 entries): examples include ephedrine, pseudoephedrine, APAAN, safrole, piperonal, methylamine, red and white phosphorus, iodine, GBL, NPP, 4-AP, 4-piperidone, 1-boc-4-AP and PMK glycidate.
- Propionyl chloride took effect on 9 April 2026 (91 FR 11450).
- BMK glycidic acid and its esters took effect on 4 May 2026 (91 FR 16831) (DEA List I/II chart, 30 Oct 2026).
- List II (11 entries): acetic anhydride, acetone, benzyl chloride, ethyl ether, potassium permanganate, MEK, toluene, hydrochloric acid, sulfuric acid, MIBK and sodium permanganate.
- Changing the lists: the Administrator may add or delete a chemical by final rule, after a proposal published at least 30 days earlier.
Precursors that are themselves controlled substances: some precursors sit in Schedule II under 21 CFR 1308.12(g) as "immediate precursors" and are regulated as controlled substances, not listed chemicals:
- phenylacetone (8501) [13]
- 1-phenylcyclohexylamine (7460) [14]
- PCC (8603) [15]
- ANPP (8333) [16]
- norfentanyl (8366) [17]
Operator duties. These are taken from DEA's Chemical Handler's Manual, 2022 edition, which DEA says is not binding.
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Registration:
- Anyone who manufactures, distributes, imports or exports List I chemicals "must annually obtain" a DEA registration (21 CFR 1309.21).
- Handlers of List II chemicals only are not required to register, but they must keep the same records and file the same reports.
- 21 CFR 1309.24 waives registration for some activities.
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Thresholds: a transaction is "regulated" when it reaches the threshold, counted per transaction or as the monthly total (21 CFR 1310.04(f)). Chemicals with no threshold are regulated whatever the quantity. Some examples:
Chemical Threshold Piperidine 500 g Propionic anhydride 1 g Acetic anhydride 1,023 kg (250 gal) Potassium permanganate 55 kg domestic, 500 kg import/export -
Records: keep them for two years. They must show the parties, the date, the chemical and quantity, the method of transfer, and the purchaser's ID (21 CFR 1310.04, 1310.06).
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Reports to DEA:
- What to report: extraordinary quantities, unusual payment or delivery methods, and unusual losses.
- How: by phone at the earliest opportunity, then in writing within 15 days (21 CFR 1310.05).
- Mail-order sales of ephedrine, pseudoephedrine and phenylpropanolamine need monthly reports.
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Imports and exports:
- File DEA Form 486 (Form 486A for imports of ephedrine, pseudoephedrine and phenylpropanolamine) at least 15 days before release by customs (21 CFR 1313.12, 1313.21).
- The notice period drops to 3 business days for regular importers or customers.
- Imports of acetone, MEK and toluene need no 15-day notice but must be reported quarterly.
- Return declarations are due within 30 days.
- Ephedrine, pseudoephedrine and phenylpropanolamine are also subject to import and production quotas.
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Retail sales of cold medicines (Combat Methamphetamine Epidemic Act):
- Sellers of nonprescription ephedrine, pseudoephedrine and phenylpropanolamine products must self-certify with DEA every year.
- Products must be kept behind the counter, and buyers must show ID and sign a logbook.
- Limits are 3.6 g per customer per day and 9 g per 30 days, or 7.5 g per 30 days by mail order.
The thresholds above come from the 2022 manual, so they predate the 2023 to 2026 List I additions. For thresholds on those newer chemicals, see 21 CFR 1310.04(f) itself. I did not check US state laws, which can add their own precursor or pseudoephedrine rules.
Approach: I searched the DEA controlled-substance schedules (21 CFR Part 1308), which hold the Schedule II immediate precursors; the datasets hold no UK precursor register and no US listed-chemicals register. The rest comes from the Home Office pages and DEA/eCFR sources opened above.
Sources: