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The Chemical Weapons Convention (CWC) at a Glance
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Contact: Daryl G. Kimball, Executive Director, 202-463-8270 x 107

Updated: October 2015

The Chemical Weapons Convention (CWC) is a multilateral treaty that bans chemical weapons and requires their destruction within a specified period of time. The treaty is of unlimited duration and is far more comprehensive than the 1925 Geneva Protocol, which outlaws the use but not the possession of chemical weapons.

CWC negotiations started in 1980 in the UN Conference on Disarmament.  The convention opened for signature on January 13, 1993, and entered into force on April 29, 1997.

The CWC is implemented by the Organization for the Prohibition of Chemical Weapons (OPCW), which is headquartered in The Hague with about 500 employees. The OPCW receives states-parties’ declarations detailing chemical weapons-related activities or materials and relevant industrial activities. After receiving declarations, the OPCW inspects and monitors states-parties’ facilities and activities that are relevant to the convention, to ensure compliance.

The CWC is open to all nations and currently has 192 states-parties. Israel has signed but has yet to ratify the convention. A key non-signatory includes North Korea, which is believed to possess chemical weapons. Syria acknowledged it had chemical weapons in 2012, and used them on multiple occasions. On September 12, 2013, Syria sent a letter to the United Nations Secretary General which said that the Assad regime has signed a legislative decree providing the accession of Syria to the Chemical Weapons Convention. In the letter, Assad said Syria woud observe its CWC obligations immediately, as opposed to 30 days from the date of accession, as stipulated in the treaty. Syria agreed to ship out its chemical weapons and destroy its production facilities. With the help of an international coalition, Syria's declared chemical weapons were completely removed from the country by June 2014. The Assad regime continues to use chlorine gas in violation of the CWC.

North Korea is suspected of having chemical weapons. Egypt also has not signed the accord. For a complete listing of states-parties and signatories, please see http://www.armscontrol.org/factsheets/cwcsig.asp.

For more on Syria, please see here.


The Chemical Weapons Convention prohibits:

  • Developing, producing, acquiring, stockpiling, or retaining chemical weapons.
  • The direct or indirect transfer of chemical weapons.
  • Chemical weapons use or military preparation for use.
  • Assisting, encouraging, or inducing other states to engage in CWC-prohibited activity.
  • The use of riot control agents “as a method of warfare.”

Declaration Requirements

The CWC requires states-parties to declare in writing to the OPCW their chemical weapons stockpiles, chemical weapons production facilities (CWPFs), relevant chemical industry facilities, and other weapons-related information. This must be done within 30 days of the convention's entry into force for each member state.

Chemical Weapons Stockpiles—States-parties must declare all chemical weapons stockpiles, which are broken down into three categories:

  • Category 1: chemical weapons based on Schedule 1 chemicals, including VX and sarin. (See below for an explanation of “scheduled” chemicals.)
  • Category 2: chemical weapons based on non-Schedule 1 chemicals, such as phosgene.
  • Category 3: chemical weapons including unfilled munitions, devices and equipment designed specifically to employ chemical weapons.

Other weapons-related declarations states-parties must make include:

  • Chemical weapons production facilities on their territories since January 1, 1946.
  • Facilities (such as laboratories and test sites) designed, constructed, or used primarily for chemical weapons development since January 1, 1946.
  • “Old” chemical weapons on their territories (chemical weapons manufactured before 1925 or those produced between 1925 and 1946 that have deteriorated to such an extent that they are no longer useable).
  • “Abandoned” chemical weapons (abandoned by another state without consent on or after January 1, 1925).
  • Plans for destroying weapons and facilities.
  • All transfers or receipts of chemical weapons or chemical weapons-production equipment since January 1, 1946.
  • All riot control agents in their possession.

Chemical Industry—The CWC requires states-parties to declare chemical industry facilities that produce or use chemicals of concern to the convention. These chemicals are grouped into “schedules,” based on the risk they pose to the convention. A facility producing a Schedule 1 chemical is considered a Schedule 1 facility.

  • Schedule 1 chemicals and precursors pose a “high risk” to the convention and are rarely used for peaceful purposes. States-parties may not retain these chemicals except in small quantities for research, medical, pharmaceutical, or defensive use. Many Schedule 1 chemicals have been stockpiled as chemical weapons.
  • Schedule 2 chemicals are toxic chemicals that pose a “significant risk” to the convention and are precursors to the production of Schedule 1 or Schedule 2 chemicals. These chemicals are not produced in large quantities for commercial or other peaceful purposes.
  • Schedule 3 chemicals are usually produced in large quantities for purposes not prohibited by the CWC but still pose a risk to the convention. Some of these chemicals have been stockpiled as chemical weapons.

The CWC also requires the declaration of facilities that produce certain nonscheduled chemicals.

Destruction Requirements

The convention requires states-parties to destroy:

  • All chemical weapons under their jurisdiction or control.

Category 1 chemical weapons destruction must start within two years after the CWC enters into force for a state-party. States-parties must destroy 1 percent within three years of the CWC's entry into force, 20 percent within five years, 45 percent within seven years, and 100 percent within 10 years (by April 29, 2007).

The OPCW may extend these deadlines due to “exceptional circumstances,” but states-parties are supposed to destroy their entire stockpiles by April 29, 2012. In December 2006, the OPCW Executive Council granted nearly all possessors extensions of differing lengths. The only exception was Albania, which was the sole state-party nearing the complete destruction of its stockpile at that time,

The latest possessor state to join the convention, Iraq, has not been given a date by which to complete destruction. Its requirement is guided by paragraph 8, article 4, which states that destruction will take place as soon as possible. (A chart at the end of this fact sheet shows the status of each possessor state's destruction activities.)

Category 2 and 3 chemical weapons destruction must start within one year after the CWC enters into force for a state-party.

  • All chemical weapons production facilities under their jurisdiction or control.

Destruction of CWPFs capable of producing Schedule 1 chemicals must start within one year after the CWC enters into force for a state-party. States-parties must complete destruction by April 29, 2007.

Destruction of other CWPFs must start within one year after the CWC enters into force for a state-party. States-parties must complete destruction by April 29, 2002.

States-parties may request to convert CWPFs to facilities that they can use for nonprohibited purposes. Once their requests are approved, states-parties must complete conversion by April 29, 2003.

As of July 2010, 64 of the 70 CWPFs declared to the OPCW have either been destroyed (43) or converted for peaceful purposes (21).

  • Chemical weapons abandoned on other states’ territories.
  • Old chemical weapons.

On-Site Activity

The convention establishes three types of on-site activities that aim to generate confidence in states-parties’ CWC compliance. These include:

  • “Routine inspections” of chemical weapons-related facilities and chemical industry facilities to verify the content of declarations and to confirm that activities are consistent with CWC obligations.
  • “Challenge inspections” which can be conducted at any facility or location in states-parties to clarify questions of possible noncompliance. (To prevent abuse of this measure, the OPCW’s executive body can vote by a three-quarters majority to stop a challenge inspection from going forward.)
  • Investigations of alleged use of chemical weapons.


The convention encourages trade among states-parties, calling upon them not to maintain restrictions on one another that would hamper the trade of chemical-related items to be used for peaceful purposes. The convention does restrict trade with non-states-parties, outlawing the transfer of Schedule 1 and 2 chemicals.  To ensure that Schedule 3 transfers to non-states-parties are not used for purposes prohibited by the convention, the CWC requires exporting states-parties to obtain an end-use certificate from importing states.

Penalties for Noncompliance

If states-parties are found to have engaged in prohibited actions that could result in “serious damage” to the convention, the OPCW could recommend collective punitive measures to other states-parties. In cases of “particular gravity,” the OPCW could bring the issue before the UN Security Council and General Assembly.

States-parties must take measures to address questions raised about their compliance with the CWC. If they do not, the OPCW may, inter alia, restrict or suspend their CWC-related rights and privileges (such as voting and trade rights).

Sources: Arms Control Association, OPCW (http://www.opcw.org/news-publications/publications/facts-and-figures/)

Possessor States' Category I Destruction Implementation


Declared Category 1 Stockpile[1]
Revised Destruction Deadline
Remaining Stockpile

16 metric tons




Completed destruction on July 11, 2007.


1,055 metric tons




Completed destruction on March 16, 2009.

Iraq [2]

Unknown Quantity

“As soon as possible” in accordance with paragraph 8, article IV of the Convention

Sarin, Mustard and possible other agents in various states of degradation


Uncertain – many difficulties are faced in destruction of chemical stockpiles


23.6 metric tons


Lewisite, Mustard, Phosgene, Sarin, Tabun

23.6 metric tons

Uncertain because of dispute with the United States about destruction funding.


40,000 metric tons


Lewisite, Mustard, Phosgene, Sarin, Soman, VX[3]

About 21,500 metric tons as of December 2009, according to the OPCW.

Will not meet deadline; Russia estimates 2015 [4]

South Korea

605 metric tons




Completed destruction on July 10, 2008.

United States

27,771 metric tons


Binary nerve agents, Lewisite, Mustard, Sarin, Soman, VX

5449 metric tons as of January 2010.

Will not meet deadline; U.S. estimates 90% destroyed by April 2012


1. These figures are inferences from the Organization for the Prohibition of Chemical Weapons (OPCW) annual implementation reports of 2006 and 2007. Another source of information is the OPCW Note by the Technical Secretariat Review of the Operation of the Chemical Weapons Convention Since the First Review Conference, WGRC-2/S/1, The Hague, Nov. 27, 2007.

2. Iraq ratified the convention on January 13, 2009 and it entered into force a month later. Iraq possesses an unknown quantity of chemical agents stored in Bunkers 13 and 41 at the Muthanna State Establishment. Bunker 13 is the main concern, and may contain up to 15,000 liters of Sarin in different munitions in various states of decay. Bombing in the Gulf War (1990 to 1991) significantly damaged the bunker, making it too dangerous for U.N. inspectors to enter after the war. A second bunker, Number 41, was used to store chemical munitions left over after the post-war destruction effort. Due to the dangerous state of these two facilities, they were concreted over by Iraqi personnel working under the supervision of U.N. personnel. The chemical agents will have decayed in the past 16 years since being secured, but still present a formidable hazard and disposal challenge.

Because Iraq signed the convention more than ten years after the treaty came into force in 1997, it is not bound by the April 29, 2012 deadline. According to paragraph 8, article IV, Iraq must destroy its stockpiles “as soon as possible.” The nature of the stockpiles, including leaked chemical agents and possibly instable explosive charges means that destruction may take some time. The OPCW, Iraqi government and U.S. met in early 2010 to look at disposal options.

3. The Soviet Union is suspected of developing novichok binary nerve agents, which are not listed in the CWC schedules.

4. See Horner, Daniel “Russia Revises Chemical Arms Deadline,” Arms Control Today, July and August 2010, http://www.armscontrol.org/act/2010_07/RusChem

5.  The United States announced Oct. 5, 2010, that it had recently completed the destruction of 78 percent of its CW stockpile and is on pace to have 90 percent of its declared CW stockpile verifiably destroyed by April 2012.  See http://www.state.gov/t/avc/rls/149010.htm

Posted: September 13, 2013