Chemical Weapons Convention (CWC)

Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction (CWC)

The Chemical Weapons Convention (CWC) requires countries to destroy all chemical weapons and prohibits developing, stockpiling, or using chemical weapons.

  • Category
    • Chemical
  • Subcategory Multilateral
  • Ratified
  • Signed, not ratified
  • Not Signed

See Status

Ratified (193)

Signed, not ratified (1)

Not Signed (3)

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Opened for Signature

13 January 1993

Entered into Force

29 April 1997



Treaty Overview

About the Treaty

  • Depositary: UN Secretary-General

Treaty Obligations

States Parties are required not to develop, produce, otherwise acquire, stockpile or retain chemical weapons (CW), or transfer, directly or indirectly, chemical weapons to anyone; not to use chemical weapons; not to engage in military preparations for use of chemical weapons; not to assist, encourage, or induce anyone to engage in any activity prohibited to a State Party under the convention.

Each State Party is required to destroy all chemical weapons and chemical weapons production facilities it owns or possesses or that are located in any place under its jurisdiction or control, as well as any chemical weapons it abandoned on the territory of another State Party no later than 10 years after entry into force of the Convention or as soon as possible in the case of States ratifying or acceding more than 10 years after entry into force. Each State Party also undertakes not to use riot control agents as a method of warfare (Article I).

The Convention defines a chemical weapon as the following, together or separately:

a) Toxic chemicals and their precursors, except where intended for purposes not prohibited under the Convention, as long as the types and quantities are consistent with such purposes; b) Munitions and devices, specifically designed to cause death or other harm through the toxic properties of those toxic chemicals specified in Subparagraph (a), which would be released as a result of the employment of such munitions and devices; c) Any equipment specifically designed for use directly in connection with the employment of munitions and devices specified in subparagraph (b).

The Convention identifies and categorizes toxic chemicals and precursors according to their potential for chemical weapons application and extent of industrial applications. Schedule 1 lists chemicals with high potential weapons utility and little or no industrial utility. Schedule 2 singles out chemicals with some degree of commercial application and significant potential for use in weapons. Schedule 3 chemicals are generally produced in large quantities for industrial purposes and have some potential for chemical weapons application. Declarations and verification requirements are the most stringent for Schedule 1 and the least so for Schedule 3 (Article II).

Activities of the OPCW can be found here.

Verification and Compliance


Verification is conducted through a combination of reporting and routine on-site inspections of declared sites. To ensure the implementation of the Convention’s provisions, including those on verification and compliance, the Organization for the Prohibition of Chemical Weapons (OPCW) was established upon the entry into force of the Convention (29 April 1997). In addition to routine verification and recourse to a procedure for consultations, cooperation, and fact-finding, each State Party has the right to request an on-site challenge inspection of any facility or location in any other State Party for the purpose of clarifying and resolving questions concerning possible non-compliance. The challenge inspection team is designated by the Director General of the OPCW and dispatched as quickly as possible.


Compliance measures under the OPCW include: the OPCW may request that a party take measures to redress a situation in a specific period; the OPCW may restrict or suspend a party’s rights and privileges; the OPCW may recommend collective measures to States Parties, including sanctions; the OPCW may ask for an advisory opinion from the ICJ. There is also the option to refer serious violations to the UN General Assembly and Security Council. Incentives to comply with the CWC include assistance and protection against attack, such as the dispatch of emergency aid; economic and technological benefits, including the fullest possible exchange of chemistry information and technology, removal of trade and other restrictions.


Eleven countries have declared possession of existing or former CW-production facilities: Bosnia and Herzegovina, China, France, India, Iran, Japan, Republic of Korea, Russian Federation, United Kingdom, United States, and Yugoslavia. Four countries have declared CW stocks: India, Republic of Korea, Russia, and United States. Nine countries have declared old CW on their territory: Belgium, Canada, France, Germany, Italy, Japan, Slovenia, United Kingdom, and United States. Four countries have declared abandoned CW on their territory: China, Italy, Panama, and Poland.

Other Main Provisions

The Convention provides for the rendering to States Parties of protection against chemical weapons and assistance in the event of a chemical attack. States Parties undertake to facilitate the fullest possible exchange of chemicals, equipment, and scientific and technical information relating to the development and application of chemistry for purposes not prohibited under the Convention. States Parties are obliged to provide data on the import and export of scheduled chemicals, as well as on facilities and chemical production. Restrictions on transfers of Schedule 1 and 2 chemicals to States not party to the Convention entered effect at entry into force and on 29 April 2000, respectively. Those on Schedule 3 transfers will be considered effective five years from entry into force. Each State Party is required to enact national implementing legislation to, inter alia, prohibit individuals under its jurisdiction or control from engaging in activities prohibited by the Convention. Each State Party is obligated to designate or establish a national authority to serve as the focal point for liaison with the OPCW and with other States Parties.

Integration with Other Treaties and Agreements

Several agreements exist that overlap with the mandate of the CWC. The Australia Group (AG), for example, coordinates CW-related export controls and encourages related intelligence sharing among its 32 member countries. The Proliferation Security Initiative strives to prevent the transfer of all weapons of mass destruction (WMD), including chemical weapons. More broadly, UN Security Council Resolution 1540 requires all states to take all possible measures to prevent the proliferation of WMD. In some cases, such as the Australia Group, countries perceive a conflict between mandates. For example, some states complain that the AG restricts the free trade in chemicals and chemical process equipment to CWC members in good standing with the OPCW and the CWC.

Point of Contact

Director-General Ambassador Fernando Arias (Spain)
Johan de Wittlaan 322517 JR, The Hague
The Netherlands
Phone: 31-70-416-33-00
Fax: 31-70-306-35-35
E-mail: [email protected]




The 5th review conference of the CWC was held from 15-19 May 2023. The conference, held every five years, was aimed at evaluating the CWC’s status of implementation and setting priorities for the OPCW for the upcoming years. The conference discussed topics such as the role of the OPCW and the CWC in strengthening international peace and security, including preventing the re-emergence of chemical weapons; maintaining readiness to respond to the use or threats of use of chemical weapons; reviewing science and technology developments relevant to the CWC’s implementation; and promoting peaceful uses of chemistry and ensuring safe production and secure use of chemicals. At the end of the conference, the CWC member states unable to agree on a consensus final outcome document.

On 7 July 2023 the U.S. Department of Defense announced that the destruction of the U.S.’s chemical weapons stockpile was complete. The OPCW later verified this announcement, noting that this development marked the destruction of all declared chemical weapons stockpiles.

The 28th Session of the Conference of the States Parties (CSP-28) to the CWC was held in The Hague, Netherlands from 27 November to 1 December 2023. Ambassador Suljuk Mustansar Tarar of Pakistan served as the Chairperson. Key topics included the potential possession of chemical weapons by the Syrian Arab Republic, the OPCW’s increased contacts with South Sudan, the war in Ukraine, and the conflict in Gaza.


The 27th Session of the Conference of the States Parties (CSP-27) to the CWC was held in The Hague, Netherlands from 28 November to 2 December.

On 29 April, the OPCW celebrated the 25th anniversary of the entry into force of the CWC.



On 30 November, States Parties to the CWC re-appointed H.E. Mr. Fernando Arias of Spain as Director-General of OPCW for his second term.

The 26th Session of the Conference of the States Parties to the CWC opened in The Hague, Netherlands on 29 November.

On 21 April, the 25th Session of the Conference of the States Parties to the CWC adopted a decision to suspend certain rights and privileges of the Syrian Arab Republic due to chemical weapons activity, including suspension of the right to vote in the Conference and the Council, to stand for election to the Council, and to hold any office of the Conference, the Council, or any subsidiary organs.


On 1 December, the OPCW observed the annual Day of Remembrance for All Victims of Chemical Warfare during the 25th Session of the Conference of States Parties.

On 7 June, two decisions (C‑24/DEC.4 and C‑24/DEC.5) adopted by CSP-24 came into force, adding four additional entries to the list of Schedule 1 (A) chemicals under the Convention. The chemicals included two families of Novichok agents, an individual Novichok agent, and two families of carbamates.

On 9 July, the OPCW Executive Council (EC) adopted a decision condemning the possession and use of chemical weapons by the Syrian Arab Republic and requesting certain measures from the Syrian Arab Republic to address the situation.

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