Guidance

Chemical Weapons Convention guidance

Guidance for those producing, processing, consuming, possessing, importing or exporting chemicals covered by the Chemical Weapons Convention (CWC).

From:
Department for Energy Security and Net Zero
Published
30 May 2013
Last updated
3 September 2025 — See all updates

The Chemical Weapons Convention

The UK is one of 193 States Parties to have ratified the Chemical Weapons Convention (CWC), the first arms-control treaty to introduce a verifiable ban on an entire class of weapons of mass destruction.

The CWC entered into force on 29 April 1997 and all member states must agree to its provisions, which include:

  • to chemically disarm by destroying all stockpiles of chemical weapons, any facilities which produced them and any old or abandoned chemical weapons from the past
  • never to develop, produce, stockpile or use chemical weapons
  • to submit regular declarations to the Organisation for the Prohibition of Chemical Weapons (OPCW) on the production, processing, consumption, and import and export of certain dual-use chemicals
  • to allow the OPCW to carry out inspections on their territories

The OPCW based in The Hague is the international implementing body for the CWC. It promotes and verifies adherence to the Convention and works on the behalf of States Parties. The UK fully supports the OPCW’s mission to achieve a world free of chemical weapons and in which chemistry is used for peace, progress and prosperity.

CWC UK National Authority

The UK National Authority (UKNA) is based in the Department for Energy Security and Net Zero (DESNZ) and is responsible for managing the implementation of the CWC throughout the UK, the Crown Dependencies and the Overseas Territories. Our powers to do this are contained in the Chemical Weapons Act 1996 (The Act). The Act sets out the legal obligations on those producing, processing, consuming, possessing, importing or exporting certain toxic chemicals.

To fulfil the UK’s obligations and ensure compliance with the CWC, as well as safeguarding and promoting the peaceful use of chemicals, the UKNA:

  • compiles annual declarations on relevant UK chemical activities and submits them to the OPCW
  • facilitates all OPCW inspections at UK facilities / sites
  • operates a licensing regime for Schedule 1 chemicals
  • enforces relevant export and import licensing regulations in conjunction with the Department for Business and Trade (DBT)

The UK Chemical Weapons Convention National Authority (PDF, 140 KB, 1 page)

CWC legislation

Classification of chemicals

Certain toxic chemicals and their precursors are split into three categories under the CWC and subject to legal obligations:

  • Schedule 1 - produce, acquire, possess, process / consume / or otherwise use, import or export
  • Schedule 2 - produce, process, consume, import or export
  • Schedule 3 - produce, import or export

If you carry out any of the above activities with any relevant chemical(s) you must comply with all pertinent legal requirements. A full list of scheduled chemicals and their precursors are listed in the 3 attachments below and can also be found on the OPCW website.

The CWC also places legal requirements on unscheduled discrete organic chemicals (DOCs).

Schedule 1 chemicals

Schedule 1 chemicals are especially hazardous and pose a high risk. They include nerve and blister agents and have been developed, produced, stockpiled and used as chemical weapons. They have little to no use for activities not prohibited by the CWC.

The production, acquisition, possession, use and transfer of Schedule 1 chemicals is restricted to pharmaceutical, research, medical and protective purposes. The CWC places a limit on the annual aggregated amount of Schedule 1 chemicals that each State Party may produce:

  • production for research, medical, pharmaceutical or protective purposes must be carried out at a single small-scale facility (SSSF) that is approved by the State Party
  • production in aggregate quantities not exceeding 10kg per year may be carried out for protective purposes at one facility outside of the SSSF that is approved by the State Party
  • production in quantities of more than 100g per year for research, medical or pharmaceutical purposes may be carried out at State Party approved facilities outside of a SSSF. The aggregate quantity of production must not exceed 10kg per facility
  • synthesis of Schedule 1 chemicals for research, medical or pharmaceutical purposes, but not for protective purposes, may be carried out at laboratories in aggregate quantities of less than 100g per facility
  • the total national aggregate amount of Schedule 1 chemicals that are produced at any given time must be equal to or less than one tonne in a calendar year
  • Schedule 1 chemicals may only be transferred to other CWC States Parties, and only for research, medical, pharmaceutical, or protective purposes. Any chemicals transferred cannot then be re-transferred to a third State Party

You must be officially licensed to produce, acquire, possess, use, import or export any Schedule 1 chemicals. All licenses are approved and issued by the UKNA, except for export licences, which are approved by the UKNA but issued by the Export Control Joint Unit (ECJU) in DBT.

Schedule 1 chemicals – UK licensing regime

The UK’s Schedule 1 licensing regime includes all chemicals listed in Schedule 1 of the CWC and extends to include those which share a chemical structure. This approach reflects expert technical and legal advice as well as consultations with stakeholders.

It is fundamental to the object and purpose of the CWC, and the Schedule 1 licensing regime, that chemicals which can be or have been weaponised should fall within its scope to enable the UKNA to effectively control the possession and use of such chemicals in the UK. We also want to ensure that our licensing system is applied in a technically consistent way, so chemicals with the same structures, names and toxic properties as chemicals explicitly listed in Schedule 1 are licensable, even if they have different CAS numbers. The UK considers the molecular structure of a chemical to determine whether it is covered by Schedule 1. Therefore, isotopically labelled analogues, stereoisomers (both optical and geometric), and corresponding salts are licensable. Due to its relevance and toxicity ricin A chain is also licensable.

The table below sets out the additional licensable groups of chemicals under Schedule 1.

Schedule Isotopically labelled analogues Corresponding salts Stereoisomers
1A01 x   x
1A02 x   x
1A03 x Explicitly included x
1A04 x    
1A05 x   x
1A06 x x  
1A07 x x x
1A08 (including ricin A chain) x    
1A13 x Explicitly included x
1A14 x Explicitly included x
1A15 x x x
1A16 x x x
1B09 x    
1B10 x Explicitly included  
1B11 x   x
1B12 x   x

To avoid over-burdensome and unnecessary licensing, to ensure human safety and support medical research, we have implemented some limited exemptions. These exemptions are necessary to avoid impeding the legitimate transfer, possession and/or use of, for example, paralytic shellfish poisoning diagnostic kits and some cancer treatments which contain very small amounts of particular versions of Schedule 1 chemicals, as well as contaminated items such as clothing and environmental samples which might contain traces of Schedule 1 chemicals.

The exemptions are set out in this document: 

It is a breach of the Chemical Weapons Act 1996 to produce, acquire, possess, use or import a CWC Schedule 1 chemical without an appropriate licence issued by the UKNA. It is a breach of the Export Control Act 2002 to export a CWC Schedule 1 chemical without an appropriate licence issued by ECJU.

If you are in any doubt as to whether your activities require a CWC Schedule 1 licence, please contact the UKNA immediately for further guidance and advice.

This guidance and the exemptions will be kept under review and may be subject to change in the future.

Schedule 1 licences

Individual Licence to Possess and Use a Schedule 1 Chemical

An Individual Licence to Possess and Use a Schedule 1 Chemical is required for the possession and use of any Schedule 1 chemical for pharmaceutical, medical, research or protective purposes.

As part of the licence application, you must give details of the Schedule 1 chemical to be held and used including CAS number, reason for possession and use, quantity to be possessed and used, the location where it will be held and/or used, the supplier and contact details.

All licence applications will be checked to ensure that the chemical type and quantity is consistent with its proposed purpose. The facility where the chemical will be held needs to be approved by the UKNA for a licence to be granted.

The UKNA, along with technical experts from the Defence Science and Technology Laboratory (Dstl), will visit any facility applying for a Schedule 1 license as part of the application assessment process.  The visit will cover the CWC; licensing obligations; the intended research; a site tour; a laboratory review; personnel interviews and record keeping requirements.

The UKNA also works with the Home Office’s National Counter-Terrorism Security Office (NaCTSO), who will arrange for a local Police Counter Terrorist Security Adviser (CTSA) to visit the facility to review the adequacy of both site and personnel security.

When a licence is issued it will state the maximum amount of Schedule 1 chemical that can be held at the specified facility at any one time during a given period, along with the purpose for which it is being held. Once a licence is granted, accurate records regarding the possession and use of the chemical specified on the licence must be maintained and these will be subject to inspection by the UKNA. A copy of the records must also be sent to the UKNA within 14 days of the expiry of the licence.

A licence can be granted to possess and use multiple Schedule 1 chemicals.

Individual Licence to Produce, Possess and Use a Schedule 1 Chemical

An Individual Licence to Produce, Possess and Use a Schedule 1 Chemical is required for the production of any Schedule 1 chemical for pharmaceutical, medical, research or protective purposes.

As part of the licence application, you must give details of the Schedule 1 chemical to be produced, held and used including the CAS number, reason for production, possession and use, quantity to be produced, possessed and used and the location where it will be produced, held and used.

All licence applications will be checked to ensure that the chemical type and quantity is consistent with its proposed purpose. The facility where the chemical will be held needs to be approved by the UKNA for a licence to be granted.

The license application and assessment process is the same as applying for an Individual Licence to Possess and Use a Schedule 1 Chemical, set out above.

When a licence is issued it will state the maximum amount of Schedule 1 chemical that can be produced and held at the specified facility at any one time during a given period, and the purpose of the production and for which it is being held. Once a licence is granted, accurate records regarding the production and use of the chemical specified on the licence must be maintained and these will be subject to inspection by the UKNA. A copy of the records must also be sent to the UKNA within 14 days of the expiry of the licence.

A licence can be granted to produce, possess and use multiple Schedule 1 chemicals.

CWC Non-State Parties

There are 4 Non-State Parties to the CWC:

  • Egypt
  • Israel
  • North Korea
  • South Sudan

Taiwan and Kosovo are also considered Non-State Parties for the purposes of imports and exports.

The import and export of Schedule 1 and Schedule 2 chemicals to and from any Non-State Party is strictly prohibited by the CWC.

There are specific conditions governing the export of mixtures containing Schedule 2 chemicals and the export of Schedule 3 chemicals to Non-State Parties, these are set out in the following sections.

If you are in any doubt about the legal requirements concerning the import and export of CWC chemicals you must contact the UKNA.

Importing and exporting Schedule 1 chemicals

The import and export of Schedule 1 chemicals is only permitted to and from other CWC State Parties and must:

  • only be for research, medical, pharmaceutical, or protective purposes; and of the types and quantities strictly limited to those which can be justified for such purposes; and
  • not be re-transferred to or from a third State Party

Schedule 1 chemicals are strictly prohibited from being imported and exported to and from the UK by any CWC Non-State Parties.

Any person wishing to import or export any CWC Schedule 1 chemicals must ensure that either they, or the possessor of the chemicals (if it is to be exported directly from another entity), already holds a relevant CWC Schedule1 chemical possession licence issued by the UKNA.

If you plan to import any Schedule 1 chemicals you need to apply to the UKNA for an import license at least 60 days in advance of the proposed shipment date. This enables the UKNA to liaise with the exporting State Party and notify the OPCW at least 30 days in advance, as required by the CWC, before the license can be issued.

If you plan to export any Schedule 1 chemicals from the UK you need to apply to ECJU for an export license. The UKNA must also be informed of any such intended export at least 60 days in advance of the proposed date of shipment. This will enable the UKNA to liaise with the importing State Party and notify the OPCW at least 30 days in advance, as required by the CWC.

Important Note: Saxitoxin medical / diagnostic notification allowance

The export of the CWC Schedule 1 chemical saxitoxin, in quantities of 5 milligrams or less and only for medical / diagnostic purposes, must be reported to the UKNA at least 1 working day in advance of the proposed date of shipment.

Import and export licence requirements

Anyone contemplating importing or exporting any Schedule 1 chemicals to and from the UK must first contact the UKNA.

Import licence applications must be submitted to the UKNA.

Export licence applications must be submitted to the Export Control Joint Unit (ECJU) in DBT.

An export license may also be required for intended exports of CWC Schedule 2 and 3 chemicals, including any Schedule 2 and Schedule 3 chemicals that are contained in mixtures at low concentrations and are intended for States Not Party to the CWC. For information and advice please contact the ECJU.

Import and export obligations for Schedule 2 and Schedule 3 chemicals

There are no restrictions on the importation or exportation of Schedule 2 or 3 chemicals to or from other CWC States Parties.

Schedule 2 chemicals are prohibited from being imported and exported to and from the UK by CWC Non-State Parties.

Chemical mixtures containing low concentrations of Schedule 2 chemicals can be imported and exported to and from CWC Non-State Parties where they are:

  • goods or chemical mixtures which contain 1% or less by weight of a Schedule 2A or 2A* chemical
  • goods or chemical mixtures which contain 10% or less by weight of a Schedule 2B chemical
  • consumer goods packaged for retail sale for personal or individual use

If you export any Schedule 3 Chemicals from the UK to a CWC Non-State Party you must receive a completed End-user certificate (EUC) form stating the following in relation to the transferred chemicals(s):

  • that they will only be used for purposes not prohibited under the Chemical Weapons Convention
  • that they will not be re-transferred
  • their types and quantities
  • their end-use(s); and
  • the name(s) and address(es) of the end-user(s)

The certificate must be issued by an FCDO recognised competent government department or ministry within the recipient country.

The ECJU requires the completion of an End-User Undertaking (utilising the EUC), as part of the application process for the required export licence, to meet the above CWC end-user obligations.

Exports from the UK of Schedule 3 chemicals in mixtures, at low concentrations, to Non-State Parties do not require an end-use certificate under the CWC when they are:

  • products containing thirty per cent (30%) or less by weight of a Schedule 3 chemical; and/or
  • consumer goods that are either packaged for retail sale for personal use or packaged for individual use.

Annual Declarations

The UKNA is legally required to submit annual declarations on certain chemical activities in the UK to the OPCW. This is a key aspect of the Convention’s non-proliferation objectives. Declarations from individual sites are based on the type of chemicals, activities and amounts.

You are legally required to submit a declaration to the UKNA if you:

  • produce, process, consume, import or export any quantity of CWC Schedule 2 chemicals
  • produce, import or export any quantity of CWC Schedule 3 chemicals
  • produce above 200 tonnes of discrete organic chemicals (DOC), or above 30 tonnes of any individual DOC containing the elements phosphorus, sulphur or fluorine (DOC/PSF)

Declarations are divided into 3 annual exercises.

Annual Past Declaration (APD)

To be submitted by anyone who, in the previous calendar year, produced, processed and/or consumed any Schedule 2 chemicals, and/or produced any Schedule 3 chemicals and/or unscheduled discrete organic chemicals (DOCs) above the CWC’s declaration thresholds:

  • Sch 2A        100 kg
  • Sch 2A*      1 kg
  • Sch 2B        1 tonne
  • Sch 3           30 tonnes
  • DOC/PSF   30 tonnes
  • DOC                200 tonnes

Annual Anticipated Declaration (AAD)

To be submitted by anyone who anticipates, in the next calendar year, producing, processing and/or consuming any Schedule 2 chemicals and/or producing any Schedule 3 chemicals, above the CWC’s declaration thresholds:

  • Sch 2A        100 kg
  • Sch 2A*      1 kg
  • Sch 2B        1 tonne
  • Sch 3           30 tonnes

Aggregate National Data (AND)

To be submitted by anyone who, in the previous calendar year, produced, processed, consumed, imported and/or exported any Schedule 2 chemicals, and/or produced, imported and/or exported any Schedule 3 chemicals, in any quantity below the CWC’s declaration thresholds.

Schedule 2 and Schedule 3 quantities below the CWC’s APD and AAD declaration thresholds, as set out above, are still required to be declared as part of the AND declaration, hence all activities are subject to a >0 declaration threshold, as set out in the following table.

Minimum Declaration Threshold for Schedule 2, Schedule 3 and DOC Chemicals

Activity Schedule 2A* Schedule 2A Schedule 2B Schedule 3 DOC-PSF
Production >0 >0 >0 >0 200 Tonnes of DOC chemicals, 30 Tonnes of an individual PSF chemical
Processing >0 >0 >0 Not required Not required
Consumption >0 >0 >0 Not required Not required
Import >0 >0 >0 >0 Not required
Export >0 >0 >0 >0 Not required

Making a declaration

In order to complete a declaration you need to register with the UKNA’s online Declaration Database. Once registered you can then provide details of your company’s Secretary or Registrar as the legal contact for your site(s). You will then be assigned to your site(s).

See the guidance on how to register on the Declaration Database and complete a declaration:

Once you are registered to use the database you will receive the documentation for the different declaration exercises when they are commissioned. We have produced guidance on how to complete each specific declaration.

The OPCW Handbook on Chemicals identifies individual chemicals covered by the 3 Schedules in the CWC.

If you require further information, guidance or technical support, please contact the UKNA - see Contact details.

What happens to the information I declare?

Once a declaration exercise has been completed the UKNA will submit the information to the OPCW. All information submitted is subject to UK and OPCW confidentiality agreements and is security protected.

CWC inspections

If you submit either an Annual Anticipated and/or an Annual Past Declaration you may be selected for an inspection by the OPCW if your activities are above the CWC’s verification thresholds. Inspections are not carried out at sites that solely submit Aggregated National Data declarations.

The inspection process provides a confidence-building measure that each State Party is meeting its obligations under the Convention and acts as a deterrent against any intention to contravene the Convention’s provisions.

Who is inspected?

The OPCW only routinely inspect sites that have submitted Annual Anticipated and/or an Annual Past Declaration involving certain quantities of Schedule 2, Schedule 3 and Discrete Organic Chemicals above the verification thresholds shown in the table below.

Detailed information on OPCW Inspections, including what is expected and how to prepare:

Verification Threshold for Schedule 2, Schedule 3 and DOC chemicals

Activity Schedule 2A* Schedule 2A Schedule 2B Schedule 3 DOC-PSF
Production 10kg 1 Tonne 10 Tonnes 200 Tonnes 200 Tonnes of DOC and DOC-PSF chemicals,
Processing 10kg 1 Tonne 10 Tonnes n/a n/a
Consumption 10kg 1 Tonne 10 Tonnes n/a n/a
Import n/a n/a n/a n/a n/a
Export n/a n/a n/a n/a n/a

Due to the hazardous, high risk and limited commercial use of Schedule 1 chemicals they are subject to different declaration and verification requirements compared to Schedule 2, Schedule 3 and DOC chemicals. There are no industrial facilities within the UK producing Schedule 1 chemicals in quantities requiring declaration or inspection under the CWC.

DESNZ has the legal authority to prosecute companies or individuals if they do not comply with the Chemical Weapons Act 1996.

Here you can find examples of past prosecutions under the Chemical Weapons Act and other legislation:

Contact details

Email

cwcna@energysecurity.gov.uk

Phone

  • For CWC declarations and licensing enquiries: 0300 068 5941
  • For OPCW Inspections: 0300 068 5925/5939

In writing

Department for Energy Security and Net Zero
CWC UK National Authority
3-8 Whitehall Place
London
SW1A 2AW

Updates to this page

Published 30 May 2013
Last updated 3 September 2025 show all updates

  1. Changes made to the UK processes and policy.

  2. Schedule 1 chemicals – UK licensing regime and Schedule 1 list of toxic chemicals updated.

  3. Ricin A chain added to Schedule 1 licensing regime as of 1 January 2020.

  4. Schedule 1 Chemicals – changes to licence requirements.

  5. Change to Schedule 1 licensing policy

  6. First published.

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