The Organisation for the Prohibition of Chemical Weapons (OPCW)

The Organisation for the Prohibition of Chemical Weapons (OPCW) is the implementing body for the Chemical Weapons Convention, which entered into force on 29 April 1997. The OPCW, with its 193 Member States, oversees the global endeavour to permanently and verifiably eliminate chemical weapons.

Mission

The OPCW’s mission is to implement the provisions of the Chemical Weapons Convention to achieve our vision of a world free of chemical weapons and the threat of their use, and in which chemistry is used for peace, progress, and prosperity.

The OPCW’s Approach

Two fundamental principles underline the OPCW’s Approach. The first is the centrality of the Convention’s multilateral character. The second is the equal application of the provisions of the Convention to all States Parties.

We do this with integrity, in an efficient, competent and cost-effective manner, and in a healthy working environment. Our work is guided and supported by the internal vision of our Organisation .

The OPCW's Aim

The ultimate aim of the OPCW is to achieve a world permanently free of chemical weapons and to contribute to international security and stability, general and complete disarmament, and global economic development.

Policies and Programmes

The Technical Secretariat proposes policies for the implementation of the Chemical Weapons Convention to the Member States of the OPCW, and develops and delivers programmes with and for them.

Programme Aims

Credible and Transparent Regime

To ensure a credible and transparent regime for verifying the destruction of chemical weapons and to prevent their re-emergence, while protecting legitimate national security and proprietary interests.

Universal Membership

To bring about universal membership of the OPCW by facilitating international cooperation and national capacity building.

OPCW by the Numbers

193 States committed to the Chemical Weapons Convention • 98% of the global population live under the protection of the Convention • 100% of the chemical weapons stockpiles declared by possessor States have been verifiably destroyed  .

What is a Chemical Weapon?

A Chemical Weapon is a chemical used to cause intentional death or harm through its toxic properties. Munitions, devices and other equipment specifically designed to weaponise toxic chemicals also fall under the definition of chemical weapons.

A common conception of a chemical weapon (CW) is of a toxic chemical contained in a delivery system such as a bomb or artillery shell. While technically correct, a definition based on this conception would only cover a small portion of the range of things the Chemical Weapons Convention (CWC) prohibits as ‘chemical weapons’.

Under the CWC, the definition of a chemical weapon includes all toxic chemicals and their precursors, except when used for purposes permitted by the Convention – in quantities consistent with such a purpose.

Chemical Weapon Definition in Three Parts

1-Toxic chemicals and their precursors

Toxic chemicals are defined as ‘any chemical which through its chemical action on life processes can cause death, temporary incapacitation or permanent harm to humans or animals’.

This includes all such chemicals, regardless of their origin or of their method of production, and regardless of whether they are produced in facilities, in munitions or elsewhere.

Precursors are chemicals that are used for the production of toxic chemicals.

2-Munitions or devices

Any munitions or devices specifically designed to inflict harm or cause death through the release of toxic chemicals.

Among these could be mortars, artillery shells, missiles, bombs, mines or spray tanks.

3-Equipment ‘directly in connection’ with munitions and devices

Any equipment specifically designed for use ‘directly in connection’ with the employment of the munitions and devices identified as chemical weapons.

Examples of CWs include, but are not limited to:

·       Fully developed chemical weapons and the components of such weapons when stored separately (e.g. binary munitions).

·       Chemicals used to produce chemical weapons (precursors).

·       Chemicals used to cause intentional death or harm.

·       Items with peaceful civilian uses, when used or intended for chemical weapons use (dual-use items).

·       Munitions and devices intended for the delivery of toxic chemicals.

·       Equipment directly in connection with aforementioned munitions and devices.

The full and legal definition of a Chemical Weapon can be found in Article II of the Chemical Weapons Convention.

General Purpose Criterion – Intent

A toxic or precursor chemical may be defined as a chemical weapon depending on its intended purpose.

A toxic or precursor chemical is defined as a chemical weapon unless it has been developed, produced, stockpiled or used for purposes not prohibited by the Convention.

Any chemical intended for chemical weapons purposes, regardless of whether it is specifically listed in the Convention or its Annexes (including the three schedules of chemicals) is considered a chemical weapon.

The CWC does not expressly state what ‘chemical weapons purposes’ are. Rather, it defines purposes that are not prohibited by the Convention.

Principle of Consistency

A toxic chemical held by a State Party in agreement with the “Principle of Consistency” must be produced, stockpiled or used for a legitimate purpose, and be of a type and quantity appropriate for its “peaceful” purpose.

Any chemical intended for chemical weapons purposes, regardless of whether it is specifically listed in the Convention, its Annexes or the three schedules of chemicals, is considered a chemical weapon.

Legitimate Uses of Chemicals

While providing for the prevention of production or stockpiling of chemical weapons, the definition of chemical weapons does not result in restrictions of any State Party’s right to produce and use chemicals for peaceful purposes or to acquire and retain conventional weapons and their associated delivery systems.

Eliminating Chemical Weapons

The world has agreed that chemical weapons have no place in today’s arsenals. The OPCW, together with its Member States, are committed to the complete elimination of chemical weapons stockpiles under the watchful eye of the OPCW’s verification regime.

Declarations

As a primary step toward meeting destruction obligations, the Convention requires States Parties to submit declarations on their existing chemical weapons, chemicals, materials, equipment, and facilities that could be used to produce such weapons. These declarations provide baseline data to the OPCW for planning inspections and for verifying destruction.

Declaration Timelines

Each State Party is required to submit chemical weapons related declarations to the OPCW no later than 30 days after the Convention enters into force for that State Party.

Chemical weapons related declarations include information on chemical weapons, old and abandoned chemical weapons, chemicals weapons production facilities, chemical weapons research and development facilities or establishments, and riot control agents.

A general destruction plan must also be submitted, including a schedule compatible with the destruction time frames stipulated by the Convention and by the Executive Council Decisions, a list of the types and quantities of chemical weapons to be destroyed at each chemical weapons destruction facility (CWDF), cost estimates, methods of destruction, and any issues that could adversely impact on the national destruction programme. Details about the required information as well as what is needed for submitting destruction plans and reports are specified in Parts IV and V of the Verification Annex.

Any discovery of chemical weapons after the submission of initial declaration shall be reported per Article IV.

All chemical weapons related declarations are submitted to the OPCW’s Declarations Branch for processing, evaluation, and validation. Declarations can be submitted by Member States electronically through the Secure Information Exchange (SIX) system or through their Permanent Representations to the OPCW by e-form or hard copy.

Destruction

A State Party can select and implement the appropriate destruction technologies for its chemical weapons by which chemicals are converted in an essentially irreversible way to a form unsuitable for production of chemical weapons and which – in an irreversible manner – renders munitions and other devices unusable as such. A chemical agent, for example, can be neutralised or incinerated, while unfilled munitions and other devices can simply be cut apart.

The Convention also requires States Parties to assign the highest priority to ensuring the safety of people and to protecting the environment during the implementation of its obligation. The methods employed must comply with national and international safety and emissions regulations, and cannot include open-pit burning, land burial, or dumping in any body of water.

Destruction Technologies

Chemical weapons destruction technologies have been developed to destroy assembled unitary chemical weapons (e.g., artillery projectiles, mortars, air bombs, rockets, rocket warheads, spray tanks), bulk chemical weapons agents, binary munitions and recovered chemical weapons munitions.

These technologies can be divided in two main groups:

·       high temperature destruction technologies like plasma pyrolysis, incineration and explosion chambers, with the associated off-gas treatment system;

·       low-temperature destruction technologies like neutralisation (i.e., using neutralising agents or a decontamination solution such as monoethanolamine, RD-4M or aqueous NaOH) and hydrolysis followed by secondary treatments of the resulting by-products (i.e., effluent, reaction mass or hydrolysate) like bituminisation (encapsulation), biodegratadtion or supercritical water oxidation, prior to final disposal in accordance to national regulatory provisions.

Post-treatment of the generated reaction masses that contain Schedule 2b chemicals is also required and done either by incineration, bio-treatment, or supercritical water oxidation.

Verifying Destruction

Providing confidence in destruction results

All destruction activities undertaken by Member States are required to occur under the watchful eye of the OPCW. The goal of verification activities is to confirm the complete destruction of chemical weapons, to provide confidence to States Parties regarding the integrity of the destruction process and the facility as a whole, and to ensure the non-diversion of chemical weapons.

The Technical Secretariat employs a diverse group of chemical demilitarisation inspection experts who have unimpeded access to all parts of the chemical weapons storage facilities and chemical weapons destruction facilities. These experts are responsible for inventorying the remaining stockpiles and monitoring and verifying the completion of destruction operations – in accordance with facility agreements and agreed plans for verifications.

Until the end point of destruction, demilitarisation operations are continually monitored by OPCW inspectors. Inspectors provide a continuous physical presence at the destruction facility and monitor activities with on-site instruments such as closed-circuit television, process advisory screens. Inspectors also review documentation and records they deem relevant to the conduct of their inspection.

Once completed, the State Party certifies, no later than 30 days after the destruction process has been completed, that all chemical weapons declared have been destroyed. In return, the Technical Secretariat confirms the State Parties declaration – reporting the completion of destruction of the designated quantity of chemical weapons.

Magnifying glass with chemical compound

All declared chemical weapons stockpiles destroyed

The last chemical weapon from stockpiles declared by all States Parties to the Chemical Weapons Convention was destroyed on 7 July 2023 at the Blue Grass Chemical Agent-Destruction Pilot Plant in Kentucky, USA. The OPCW has verified that the world’s declared stockpile — totalling 72,304 metric tonnes — is now irreversibly destroyed.

The mission of the OPCW, however, is not yet complete. Four States have still not joined the Convention. There are still non-stockpiled chemical weapons, including abandoned and old chemical weapons. Moreover, with thousands of new chemicals discovered every day, the threat of re-emergence of chemical weapons, also in the hands of terrorists, is more acute than ever.

Old Chemical Weapons

Old chemical weapons (OCW) must meet specific criteria concerning their date of manufacture and physical condition before they are verified as meeting the definition of an old chemical weapon. As with stockpiled chemical weapons in highly secured and safely protected storage, this includes projectiles, rockets, mortars, bombs, mines/spray dispersal devices, and spray tanks. The variety of chemical fills is much greater with chemical weapons manufactured prior to 1946, and includes fills such as mustard, phosgene, tabun, hydrogen cyanide, diphenylchlorarsine, chlorine, or stannic chloride.

Abandoned Chemical Weapons

Abandoned chemical weapons (ACW) are chemical weapons abandoned by a State after 1 January 1925 on the territory of another State without the consent of the latter. Once declared, the origin of the ACW will be verified and evidence concerning the abandonment and the identity of the Abandoning State will be established. The Abandoning State Party is responsible for providing all resources for the destruction of these items, while the Territorial State Party must provide appropriate cooperation.

Recovery and destruction of old and abandoned chemical weapons present particular difficulties for Member States because chemical weapons are frequently mixed with other types of hazardous munitions. Deterioration of explosive and safety components makes approach and contact with these items highly dangerous.

Protection of human health and preservation of the environment is one of the primary obligations for all States Parties. According to the Convention, States Parties have to maintain the highest standards where the safety of the public and the protection of the environment are concerned during chemical weapons transportation, sampling and storage as well as during destruction operations.

Concerns

The possible contamination of land and water due to the deterioration of chemical weapons that have been dumped at sea prior to 1985 or buried prior to 1977. Although the Convention does not apply to such munitions (Article IV, paragraph 17), this environmental concern may require the recovery and disposal of such obsolete munitions.

The degradation and ageing of stockpiled chemical agents and munitions in storage for over half a century. Handling and transporting munitions and containers from the storage area to the destruction facility has to be conducted in compliance with the strictest safety measures to prevent any accidental release of chemical agents.

There are also inherent risks associated with normal destruction operations, however, in most cases, they are substantially reduced by physical control safeguards (appropriate design and equipment) within the destruction facilities. There is a growing public concern on this issue regarding both the risk involved in direct exposure, as well as the long term low level exposure to agents, disposal, and degradation products.

Environmental Standards

The procedure followed to fulfil these obligations must comply with national safety and environmental standards. These national standards are declared as part of the general plan for destruction that is submitted to the OPCW Technical Secretariat by possessor states.

In addition, States Parties are required to obtain the necessary environmental permits for each chemical weapons destruction facility prior to the facility’s operations commencing. The verification measures of the Organisation will not aim at evaluating national standards or monitoring compliance with national standards. Monitoring compliance remains the responsibility of the State Party. However, the declaration of national standards is expected to contribute to the implementation of the obligation of the States Parties to safeguard the neighbouring population, the inspection personnel, and the environment during any operations involving chemical weapons.

Destruction Methods

Each State Party can determine how to destroy its chemical weapons, however, destruction methods with a high ecological impact like sea dumping, land burial, and open-pit burning are prohibited.

The selected destruction technology should minimise the risk of chemical agents being released during storage, transportation and disposal operations, as well as reduce to a minimum the public health and environmental impact from process effluents.

The destruction method adopted should achieve proper safety and environmental standards.

https://www.opcw.org/our-work/eliminating-chemical-weapon

Preventing the Re-Emergence of Chemical Weapons

“To exclude completely the possibility of the use of chemical weapons”

The Chemical Weapons Convention’s aim is “to exclude completely the possibility of the use of chemical weapons”. It does so by ensuring that all existing stockpiles of chemical weapons are destroyed, and by putting in place a framework – made up of a set of binding obligations on States Parties and a verification regime run by the Technical Secretariat – to ensure that chemical weapons do not re-emerge.

Chemical weapons may re-emerge in a number of ways: through state-sponsored programmes, through the actions of terrorist or other criminal groups, or through lone individuals. Chemical weapons may be produced by repurposing existing chemical facilities or they may be made on a smaller scale in purpose-built laboratories or even domestic settings. The OPCW works in a variety of ways to prevent these scenarios from happening.

Verification

Toxic chemicals are used around the world for many legitimate and peaceful applications, but they may also be used for purposes that are prohibited by the Chemical Weapons Convention.  Because of this, States Parties to the Chemical Weapons Convention must ensure that all toxic chemicals, and their precursors, are only used for purposes that are not prohibited by the Convention. This is a very broad obligation, which may involve a number of actions at the national level relating to matters such as chemical security, criminalisation of prohibited conduct, and the creation of a National Authority for Convention implementation.

As part of this commitment, States Parties to the Convention have obligations relating to certain toxic chemicals that are listed in the Convention and that could be used for weapons purposes. These obligations involve the collection of information and the submission of declarations regarding these chemicals, which are of varying commercial significance.

Based on the information provided in States’ declarations, OPCW inspectors visit the facilities where these chemicals are produced, processed, or consumed to ensure that the declarations are complete and accurate. These routine inspections are cooperative events—the inspection teams are concerned with verifying the contents of declarations and do not adopt an investigative approach.

Challenge Inspections

Challenge inspections are designed to clarify and resolve any questions concerning possible non-compliance by a State Party with the Chemical Weapons Convention and are one of its most innovative features. Under Article IX of the Convention, any State Party can request the Secretariat to conduct an on-site challenge inspection anywhere in the territory (or under the jurisdiction or control) of any other State Party. States Parties may not refuse a challenge inspection, regardless of the nature of the location at which it is to take place. Article IX encourages, but does not oblige, States Parties to try to clarify and resolve non-compliance concerns through consultations before requesting a challenge inspection. Challenge inspections are characterised by the ‘any time, any place’ concept: they are to be launched at very short notice and can be directed at declared or undeclared facilities and locations.

Dealing with the Threat of Terrorism

The threat of terrorists using chemicals as weapons is a significant global challenge. OPCW Member States have long recognised the threat posed to the Chemical Weapons Convention by non-State actors, and have underlined that the full and effective implementation of all provisions of the Chemical Weapons Convention is in itself a contribution to global counter-terrorism efforts. While the Chemical Weapons Convention was not designed specifically to deal with terrorism, it contains a number of provisions that can help countries to control access to toxic chemicals and related materials, and to respond effectively should the worst occur.

Prevention

Key to preventing chemical terrorism is ensuring that terrorists cannot easily access the chemicals they seek. The Chemical Weapons Convention requires its States Parties to “adopt the necessary measures” to ensure that toxic chemicals and their precursors are only used for non-prohibited purposes. The implementation of this obligation involves ensuring compliance with the requirements of the Convention’s verification regime in relation to scheduled chemicals, but it also involves putting in place controls, where considered necessary, on scheduled or non-scheduled chemicals that are susceptible to being used as weapons or in the manufacture of chemical weapons. An example of a non-scheduled chemical of security concern is chlorine, which is in very wide industrial use around the world but has also been used recently as a chemical weapon.

Possible examples of such ‘necessary measures’ include policies to ensure the security and to limit the risk of diversion of vulnerable chemicals (such as chemicals or precursor chemicals that may likely be used by non-State actors), including declaration and reporting requirements, codes of practice, export controls, and so forth.

The OPCW assists its Member States in this task by serving as a platform for the exchange of information about best practices and by providing capacity building.

Response

The Convention facilitates the exchange among States Parties of information and equipment which can help to protect populations against the effects of a chemical weapons attack. It also mandates the Technical Secretariat to provide assistance to States Parties that request it.

Legal Accountability

An important part of dealing with the threat of chemical terrorism is ensuring that those who plan or carry out such attacks are brought to justice. The Chemical Weapons Convention requires each State Party to adopt laws that criminalise all conduct that is prohibited for States by the Convention (Article VII). This means that individuals and corporations can be prosecuted in national courts if they develop, produce, otherwise acquire, retain, transfer, or use chemical weapons. The Convention also requires States Parties to provide to each other the necessary legal assistance to ensure legal accountability.

Action

A Framework for Action

An October 2017 decision by the Executive Council underscored the threat to the Convention posed by chemical terrorism.

The decision laid out a number of measures to be taken by the States Parties and the Technical Secretariat to counter this threat.

The Conference of the States Parties endorsed the decision in June 2018 and further requested the Secretariat to build capacity in OPCW Member States to prevent and respond to chemical terrorism.

Chemical Terrorism

The OPCW's Counter-Terrorism Efforts

The OPCW has a range of capacity building programmes that help Member States to prevent and respond to chemical terrorism. These range from legal workshops to first-response training.

The OPCW also works actively with the United Nations and other international organisations to ensure a coordinated response in times of emergency.

Status of the OPCW’s Contributions to Global Anti-Terrorism Efforts (February 2019)

Awareness through Education and Outreach

One of the most important ways the OPCW works to prevent the re-emergence of chemical weapons is by increasing knowledge and awareness about chemical weapons, about the work of the OPCW and the goals of the CWC, and about the importance of responsible scientific practice.

The Hague Ethical Guidelines

Ensuring an Ethos of Science for Peace

To promote a culture of responsible conduct in the chemical sciences and to guard against the misuse of chemistry, a group of chemical practitioners from around the world have formulated a set of ethical guidelines informed by the Chemical Weapons Convention – The Hague Ethical Guidelines.

The Hague Ethical Guidelines are intended to serve as elements for ethical codes and discussion points for ethical issues related to the practice of chemistry under the Convention. The OPCW encourages all stakeholders to refer to and promote the guidelines when debating the vital dimension of ethics in relation to chemical disarmament and non-proliferation and the broader issue of responsible scientific conduct.

The Key Elements

Achievements in the field of chemistry should be used to benefit humankind and protect the environment.

Sustainability

Chemistry practitioners have a special responsibility for promoting and achieving the UN Sustainable Development Goals of meeting the needs of the present without compromising the ability of future generations to meet their own needs.

Education and Outreach

Formal and informal educational providers, enterprise, industry and civil society should cooperate to equip anybody working in chemistry and others with the necessary knowledge and tools to take responsibility for the benefit of humankind, the protection of the environment and to ensure relevant and meaningful engagement with the general public.

Awareness and Engagement

Teachers, chemistry practitioners, and policymakers should be aware of the multiple uses of chemicals, specifically their use as chemical weapons or their precursors. They should promote the peaceful applications of chemicals and work to prevent any misuse of chemicals, scientific knowledge, tools and technologies, and any harmful or unethical developments in research and innovation. They should disseminate relevant information about national and international laws, regulations, policies and practices.

Ethics

To adequately respond to societal challenges, education, research and innovation must respect fundamental rights and apply the highest ethical standards. Ethics should be perceived as a way of ensuring high quality results in science.

Safety and Security

Chemistry practitioners should promote the beneficial applications, uses, and development of science and technology while encouraging and maintaining a strong culture of safety, health, and security.

Accountability

Chemistry practitioners have a responsibility to ensure that chemicals, equipment and facilities are protected against theft and diversion and are not used for illegal, harmful or destructive purposes. These persons should be aware of applicable laws and regulations governing the manufacture and use of chemicals, and they should report any misuse of chemicals, scientific knowledge, equipment and facilities to the relevant authorities.

Oversight

Chemistry practitioners who supervise others have the additional responsibility to ensure that chemicals, equipment and facilities are not used by those persons for illegal, harmful or destructive purposes.

Exchange of Information

Chemistry practitioners should promote the exchange of scientific and technical information relating to the development and application of chemistry for peaceful purposes.

Preventing the Re-Emergence of Chemical Weapons. Retrieved March 30,2025,from https://www.opcw.org/our-work/preventing-re-emergence-chemical-weapons

Supporting National Implementation of the Convention

Delivering on the Convention’s Promise

Countries must translate the obligations in the Chemical Weapons Convention into their national laws and regulations.

The intrusive nature of the Chemical Weapons Convention’s verification regime, coupled with the fact that it covers private chemical enterprises as well as government facilities, means that national measures to implement the Convention are of great importance.

Article VII of the Convention requires States Parties to adopt laws that prohibit individuals and companies from undertaking any activity prohibited by the Convention, such as making or using chemical weapons. They are also required to designate or establish a National Authority to serve as the national focal point for effective liaison with the Organisation and other States Parties. Effective implementation of the CWC has become even more important than before, in view of the new security risks and threats, in particular terrorism.

Per Article VI of the Convention, another crucial requirement for national implementation is for States Parties to adopt the necessary national measures to ensure that toxic chemicals are only used for peaceful purposes.

National Implementation

Every State Party to the Chemical Weapons Convention must implement the provisions of the Convention at the national level.

National Implementing Measures

All States Parties are required under Article VII of the Chemical Weapons Convention to adopt the ‘necessary measures’ to legally implement the CWC within their legal structures. They must then inform the OPCW of the legislative and administrative measures they have taken. Article VII contains some specific and required measures such as passing laws that criminalise certain conduct prohibited by the Convention and establishing a National Authority.

The complex nature of these obligations means that each State Party must assess the steps necessary for making sure the Convention will be implemented effectively and enforced within its jurisdiction.

Depending upon the State Party’s constitution, its existing laws, the extent of its chemical industry, or whether it has (or had) a chemical weapons programme, the steps the State Party has to take may be very few or quite extensive.

In all cases, however, a review of existing legislation is an important first step to ensure that legal implementation is consistent and effective

Article VI requires the adoption of measures to ensure that toxic chemicals and their precursors are only used for purposes not prohibited by the Convention.

Article XI and the Verification Annex require Member States to ensure that the international trade of scheduled chemicals is controlled.

Chemical Industry

The Convention’s industrial verification regime monitors the production, processing and consumption of chemicals. Chemical industry also plays an important role in ensuring that toxic chemicals don’t fall into the wrong hands.

Chemical research

Other Commercial and Educational Entities

The Convention requires national controls on toxic chemicals which may affect commercial or research activities

Government

Each State Party is required to designate a National Authority and is granted representation in the OPCW

What does a National Authority look like?

Every State Party is different, and has discretion in determining the size, structure, composition, and mandate of its National Authority. It may either designate an existing government department or agency the task of acting as the National Authority, or establish an entirely new entity specifically for this purpose.

The National Authority can be either a centralised entity with responsibilities covering all aspects of national implementation of the Convention, or a decentralised entity acting as a liaison between the OPCW and the multiple government departments or agencies responsible for specific aspects of national implementation.

Each State Party’s particular circumstances will determine the composition, structure and mandate of its National Authority. Factors that may influence this include the types of chemical facilities the Member State possesses, the amount of resources it can allocate to implementation, or whether or not it possesses chemical weapons.

For States Parties that do not posses chemical weapons and have little or no declarable chemical industry, the National Authority can be a body consisting of just one or two people within an existing government department or ministry; for States Parties with large declarable industries or chemical weapons destruction programmes, the National Authority may be a standalone government agency.

Promoting Chemistry for Peace

Economic and Technical Development through Chemistry

Although the Chemical Weapons Convention is primarily designed to eradicate chemical weapons and to prevent their re-emergence, it also contains important provisions relating to the promotion of free trade in chemicals and the open exchange of information and knowledge about the peaceful applications of chemistry.

The Preamble to the Convention promotes these activities as helping to strengthen economic and technological development of all States Parties. Yet, Article I of the Convention prohibits States Parties from assisting or encouraging other States in any way to produce chemical weapons. The Convention also restricts the production of many ‘dual-use’ chemicals, such as those that could be used both in the illegal production of chemical weapons and for peaceful chemical processes.

Ensuring the ban on chemical weapons is upheld, while promoting and facilitating the peaceful exchange of knowledge and trade of chemicals to support the development of States Parties, is a very delicate balancing-act. It requires the OPCW and States Parties to work together to support capacity-building as well as to strive for transparency and cooperation.

Economic and technological development is very important for States Parties, and thus it is one of the foundations within the Convention. Article XI relates specifically to economic and technological development.

States Parties are encouraged to cooperate internationally in the field of chemistry, and are encouraged to exchange scientific and technical information relating to the whole chemical lifecycle as long as it is for purposes not prohibited under the Convention. These ‘purposes not prohibited’ are located in Article II, which includes the following:

Industrial, agricultural, research, medical, pharmaceutical or other peaceful purposes;

Protective purposes, namely those purposes directly related to protection against toxic chemicals and to protection against chemical weapons;

Military purposes not connected with the use of the chemical weapons and not dependent on the use of the toxic properties of chemicals as a method of warfare; and

Law enforcement including domestic riot control purposes.

In the broadest sense, the OPCW and States Parties should work together to facilitate building and sharing chemical knowledge in ways that support peace and development within and between States Parties. To achieve this, the OPCW provides specific training and workshops to support capacity building and knowledge sharing in States Parties, acts as a forum for consultation and information sharing, and undertakes projects to engage with wider audiences and non-traditional stakeholders to raise-awareness of the Chemical Weapons Convention.

Article XI states:

The provisions of this Convention shall be implemented in a manner which avoids hampering the economic or technological development of States Parties, and international cooperation in the field of chemical activities for purposes not prohibited under this Convention including the international exchange of scientific and technical information and chemicals and equipment for the production, processing or use of chemicals for purposes not prohibited under this Convention.

Fostering Peaceful and Secure Uses of Chemistry

The provisions of the CWC have to be effectively and stringently implemented to ensure that a global chemical weapons ban is achieved.  Support programmes enhance the OPCW’s ability to check prohibited activity and to extend the benefits of peaceful uses of chemistry to all.

The Secretariat runs a number of programmes, services, and projects that support the exchange of information, equipment, and chemicals as well as foster the peaceful use of chemistry.

These initiatives bring together people from around the world to share knowledge and practices, learn about the Convention, build and foster relationships, and ultimately support the implementation of the Convention and strengthen the prohibition of chemical weapons.

These programmes focus on the need for strengthening economic and technological development through capacity building, facilitating exchanges of chemicals, equipment and scientific and technical information in the context of the development and uses of chemistry for purposes not prohibited under the Convention.

Chemistry for Peace

Peaceful Uses of Chemistry

Peaceful and legal uses for chemistry include industrial, agricultural, research, medical, pharmaceutical, and protective purposes.

Enhancing Laboratory Capabilities

To maintain and increase the capacity of States Parties to fully implement the CWC, the Secretariat provides expert support to build and maintain the technical capabilities of analytical chemistry laboratories globally.

The OPCW has its own accreditation scheme through which it can determine ‘OPCW Designated’ laboratories around the world. This means the laboratory is of a high standard in regard to its chemical analysis capabilities as proven through a series of proficiency tests organised by the OPCW. This designation means the laboratory can receive samples for analysis from OPCW field missions and directly support the scientific expertise of the OPCW’s work. The Secretariat sponsors visits by experts to laboratories in States Parties to assess, among other things, long-term technical measures needed to help laboratories meet the criteria for OPCW designation.

Similar assistance is also rendered to laboratories that want to improve their capabilities without seeking OPCW designation. In addition to support for staff training, internships, and participation in scientific conferences, the Secretariat can assist with establishing quality assurance systems or preparing quality manuals.

The Secretariat can provide advice to States Parties on the best practices and appropriate technologies needed to destroy chemical weapons, including old or abandoned ones, as well as technical specifications and advice on inspection equipment. A variety of software is also available to the laboratories and specialised institutions in States Parties, including analytical chemistry databases and software that ensures the security of declaration data and enables exchanges of data between States Parties and the OPCW. The Secretariat supports staff training, visits to designated laboratories, and internships at international laboratories, and the OPCW Centre for Chemistry and Technology near The Hague.

What is a Designated Lab?

A Designated Laboratory can receive samples for analysis from OPCW field missions and directly supports the scientific expertise of the OPCW’s work .

Ensuring Preparedness

Building Protective Capacity Against Chemical Weapons

The Chemical Weapons Convention outlaws chemical weapons, but it also recognises that States Parties will still wish to protect themselves and their populations against the possibility that chemical weapons may be used against them. For this reason, States Parties are permitted to develop national protection programmes against chemical weapons and the Convention ensures that they can receive assistance, if they require it, to build their national capacity to respond to the use of chemical weapons. The OPCW provides specific programmes in this area, including detection and alarm systems, protective and decontamination equipment, training on medical assistance and treatment, and advice on protective measures.

Assistance Agreements

The first agreement regarding the provision of assistance upon demand was between the Islamic Republic of Iran and the OPCW. It concerned the provision of emergency medical assistance teams and facilities for treating chemical weapon casualties at Iranian hospitals.

Rights and Responsibilities of States Parties

Along with activities related to industry, agriculture, research, medicine and pharmaceuticals, the CWC does not prohibit the development of means of protection against toxic chemicals and chemical weapons. States Parties also have the right to participate in, and the obligation to facilitate, the fullest possible exchange of equipment, material and scientific and technological information concerning means of protection. States Parties may even transfer to other States Parties or use limited amounts of Schedule 1 chemicals (i.e., those with few if any non-weapons applications) for research, medical, pharmaceutical and protective purposes.

Because of concerns that the knowledge and equipment acquired in developing national protective programmes could facilitate the proliferation of chemical weapons, the Convention requires States Parties to submit information every year regarding their national protection programmes to the OPCW Technical Secretariat. Additionally, details of the production, uses and transfers of Schedule 1 chemicals must be reported. All of these requirements are intended to increase the transparency of all national protective programmes.

Building Readiness to Respond

Not all States Parties have the capabilities required to respond to a chemical weapons attack. Because of this, the Convention ensures that outside support is available to those that need it in building their national protective capability against chemical weapons

Article X of the Convention requires the Secretariat to make information available and provide advice to States Parties concerning means of protection and the implementation of national protection programmes. It does this through a data-bank of information and through courses and workshops on protection and civil defence. The Secretariat organises trainings for first responders, government experts and emergency response units designed to build and develop national and regional capabilities and emergency response systems against the use, or threat of use, of chemical weapons.

The Secretariat has solicited the cooperation of States Parties for this purpose as well. The Protection Network is a group of experts nominated by States Parties who are involved in the emergency response to, and assistance and protection against, toxic chemicals. The group provides advice to the Secretariat on the implementation of Article X.

Ensuring Emergency Assistance

Should the worst occur, States Parties are also required to offer assistance to others, through the OPCW. This assistance can take three forms. First, States Parties may contribute to the Voluntary Fund for Assistance, as these are funds to be used to provide assistance if a State Party is attacked or threatened with chemical weapons.

Second, States Parties may enter into agreements with the OPCW regarding the provision of assistance upon demand. The first agreement of this kind—a memorandum of understanding between the Islamic Republic of Iran and the OPCW—concerned the provision of emergency medical assistance teams and facilities for treating chemical weapon casualties at Iranian hospitals.

Third, States Parties may decide to declare the kind of assistance they might provide in response to an appeal by the OPCW to support another State Party under attack with chemical weapons or under threat of attack. Many States Parties have made such offers of assistance. Notably, Switzerland has offered to provide equipment for assistance efforts, as well as to train relevant personnel from other States Parties in its use. Consequently, Switzerland and the Secretariat have jointly organised numerous training courses at the Swiss Federal Institute for Nuclear, Biological and Chemical Protection in Spiez, Switzerland.

Support rendered to the OPCW does not in any way preclude States Parties from requesting and providing assistance bilaterally and entering into independent individual agreements concerning the procurement or provision of emergency assistance. States Parties are also free to request or provide such assistance even in the absence of an agreement. Regardless of whether or not a State Party has made a specific commitment to the OPCW to provide assistance, it must make every effort to do so if called upon by the Director-General in response to a request for assistance.

Responding to the Use of Chemical Weapons

The Chemical Weapons Convention codified an international norm against chemical weapons, to which all States Parties must adhere. Protecting this norm requires constant vigilance. While the work of the OPCW is largely focused on preventing the use of chemical weapons – through its verification activities, destruction of existing stockpiles, and capacity building in Member States –, it must also be ready to respond if and when chemical weapons are used. There are different ways in which the OPCW can respond to the use or alleged use of chemical weapons, ranging from carrying out a formal investigation to providing emergency assistance.

If a Member State considers that chemical weapons have been used against it, or it is threatened by actions prohibited by the Convention, it can request assistance from the OPCW.

Article X of the Convention sets out the procedure for requesting and receiving assistance against the use of chemical weapons. If there is proof that there are victims due to the use of chemical weapons and immediate action is indispensable, the Director-General is authorised to take emergency measures of assistance.

Investigations of Alleged Use

The Chemical Weapons Convention provides for investigations to be carried out by the Secretariat in connection with allegations of the use of chemical weapons under certain conditions. These investigations are technical in nature and are designed to establish whether or not chemical weapons have been used and identify the need for assistance to States Parties. If, in the course of the investigation, information is collected that may serve to identify the origin of any chemical weapons used, such information is to be included in the investigation report.

There are two ways in which an investigation of alleged use (IAU) of chemical weapons can be triggered. Both involve requests from States Parties. Articles IX and X of the Convention describe the applicable procedures. The first is by submission of a request by a State Party for a challenge inspection under Article IX where the alleged use occurred in another State Party. The second is by submission of a request for assistance in accordance with Article X in a situation in which chemical weapons are alleged to have been used against the requesting State Party, or riot control agents are alleged to have been used against it as a method of warfare. In the case of a request for assistance under Article X, an IAU is conducted with two purposes: 1) to establish facts related to the alleged use of chemical weapons, and 2) to provide a basis upon which the Executive Council can adopt a decision with regard to whether or not to instruct the Secretariat to take further action to assist the requesting State Party.

Once an IAU has been triggered under Article X of the Convention, the Director-General will dispatch an inspection team at the earliest opportunity. Upon entering the State Party in question, the inspection team is to have the right to access any areas that could have been affected by the alleged use of chemical weapons and other areas, such as hospitals and refugee camps. Members of the team may collect chemical, environmental and biomedical samples for analysis on-site or off-site at OPCW-designated laboratories. Inspection team members may also interview victims, eyewitnesses and medical personnel and participate in autopsies of persons who may have been affected by the alleged use of chemical weapons. Within 24 hours of arriving in the State Party having requested assistance under Article X of the Convention, the inspection team is to send a situation report to the Director-General. A preliminary report is to be submitted within 72 hours of the inspection team’s return to the OPCW’s headquarters in The Hague, while a final report is to be submitted within 30 days of the inspection team’s return. The Director-General is to transmit these reports to the Executive Council and to all States Parties. The Executive Council is to consider the reports and adopt decisions, as appropriate.

The OPCW may also conduct investigations under Article X in cases of alleged use of chemical weapons by or in States not Party to the Convention. In this line, pursuant to the Convention, the OPCW is to cooperate closely with the Secretary-General of the United Nations in connection with alleged uses of chemical weapons in States not Party to the Convention or in a territory not controlled by States Parties. If so requested, the Organisation is to put its resources at the disposal of the United Nations. Such a situation occurred in 2013 when the OPCW participated in the United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic, which was not then a State Party to the Convention. Investigators interviewed survivors and other witnesses, identified munitions used, collected biomedical and environmental samples and sent the samples to OPCW-designated laboratories for analysis. The investigations concluded that chemical weapons had been used.

Technical Assistance Visits

The Technical Secretariat provides advice and assistance, upon request, to States Parties that do not seek an investigation or a rapid response, but do wish to benefit from the Secretariat’s technical expertise. For example, such expertise may be needed for identifying chemical agents used in an attack.  The Secretariat is mandated by the Convention to provide such technical assistance, which may include visits to the State Party concerned.

During a Technical Assistance Visit, experts from the Secretariat provide technical expertise, for example, in identifying chemical agents used in an attack and may include visits to the State Party concerned.

Fact-Finding Mission

In response to persistent allegations of chemical weapons use in Syria, the OPCW Fact Finding Mission (FFM) was set up in 2014 “to establish facts surrounding allegations of the use of toxic chemicals, reportedly chlorine, for hostile purposes in the Syrian Arab Republic”. The FFM is required to study available information relating to allegations of use of chemical weapons in Syria, including information provided by the Syrian Arab Republic and others.

Since May 2014, the OPCW has deployed the FFM in numerous occasions to the Syrian Arab Republic and outside of Syria and has kept States Parties informed of its work. The FFM interviews witnesses and obtains samples and physical evidence for analysis.

In 2015, the OPCW Executive Council and the UN Security Council endorsed the continual operation of the FFM.

The FFM’s findings established the facts surrounding allegations of the use of toxic chemicals as weapons in Syria and confirmed that chemical weapons had been used. The FFM’s findings were the basis for the work of the OPCW-UN Joint Investigative Mechanism (JIM), an independent body established by the UN Security Council (Resolution 2235, 7 August 2015). The JIM’s purpose was to identify the perpetrators of the chemical weapon attacks confirmed by the Fact Finding Mission. The JIM’s mandate expired in November 2017.

The OPCW has deployed the Fact-Finding Mission to investigate allegations of chemical weapons use in Syria and has kept States Parties informed of the FFM’s work.

Responding to theUse of Chemical Weapons. Retrieved March 30,2025,from https://www.opcw.org/our-work/responding-use-chemical-weapons

Supporting Victims of Chemical Weapons

The shadow cast by chemical weapons over modern history has claimed countless victims, both civilians and soldiers across the globe.

Just the mention of certain cities–Ieper, Halabja, Sardasht and Ghouta–evokes painful images of suffering and death. The OPCW honours the memory of the victims of these attacks through its mission to eliminate these weapons from the world. Our commitment to victims offers them hope that they will be the last to experience the horror of chemical warfare.

To secure a future without chemical weapons, we must protect, strengthen and extend the norm of their abhorrence enshrined in the Chemical Weapons Convention. The global norm against chemical weapons is not only a legal agreement, but also a moral declaration about the dignity of humanity.

At the same time, the OPCW recognises that survivors are not mere symbols of suffering. They are fellow humans who deserve our active support and assistance.

This is why the OPCW lends strong support to a number of endeavours that pay homage to the memory of the victims and to uphold the dignity of survivors.

Peace

The global norm against chemical weapons is not only a legal agreement, but also a moral declaration about the dignity of humanity.

Remembering All Victims of Chemical Warfare

The OPCW observes the Day of Remembrance for all Victims of Chemical Warfare annually, during the Conference of the States Parties.

During the ceremony–at which representatives of the victims’ associations participate as guests of honour–the OPCW Member States renew their resolve to achieve a world truly free of chemical weapons.

The global norm against chemical weapons is not only a legal agreement, but also a moral declaration about the dignity of humanity.

The Day of Remembrance for All Victims of Chemical Warfare is observed annually in November

Ieper Declaration

Heeding the Lessons of History

In April 2015 the world commemorated the first large-scale use of chemical weapons in Ieper, Belgium — the event that marked the advent of a new kind of warfare that would to deprive millions of their lives and health.

A re-dedication to rid the world of chemical weapons

The Ieper Declaration, issued by OPCW Member States, concludes with their determination, “to heed the lessons of history, to embrace what unites them, and to build on it”.

Mindful of the lessons of history, OPCW Member States convened in Ieper and issued a declaration restating their commitment against chemical weapons.

The “Declaration on the Occasion of the Centennial Commemoration of the First Large-Scale Use of Chemical Weapons at Ieper” reaffirms the role of the Chemical Weapons Convention as a fortification against chemical weapons and condemns their use under any circumstances by anyone.

The Declaration also makes reference to holding accountable those responsible for the use of chemical weapons, and ensuring that non-State actors never obtain chemical weapons.

Support Network for Victims of Chemical Weapons

In 2011, the Conference of the States Parties established the International Support Network for Victims of Chemical Weapons and a voluntary trust fund for this purpose.

States Parties asked the OPCW Technical Secretariat to work closely with victims’ associations to bring visibility and awareness to the history of the use of chemical weapons from a victim’s perspective, as well as resources and information for the treatment of victims of chemical weapons

Symposium on Medical Treatment of Victims of Chemical Weapons

To discuss challenges and hopes associated with providing medical assistance for victims of chemical warfare, specifically in relation to long-term health effects and the treatment necessary for these conditions, OPCW held an International Symposium on Medical Treatment of Chemical Warfare Victims.

Eyewitness Accounts

The Tehran Peace Museum’s Eyewitness Accounts project documents the experiences of survivors of chemical warfare. Read how chemical weapons forever changed the lives of victims, war veterans, youth, and professionals told through their powerful stories.

Medical Symposium Outcome Document

Symposium Declaration: International Symposium on Medical Treatment of Chemical Warfare Victims: Challenges and Hopes

In recognition of the importance of providing assistance to the victims of chemical weapons, the OPCW commissioned a manual for medical practitioners who care for the victims of chemical warfare.

The Practical Guidebook on the Medical Management of Chemical Casualties has been funded from the trust fund.

The OPCW-The Hague Award Honours Victim Advocates

The OPCW-The Hague Award is part of the legacy from the OPCW’s 2013 Nobel Prize for Peace and it seeks to recognise individuals or institutions that have made exceptional contributions toward a world permanently free of chemical weapons.

In 2015, two eminent experts who dedicated their careers to caring and advocating for the victims of chemical weapons won The OPCW-The Hague Award.

The first awardee, Dr Mahdi Balali-Mood of Iran treated large numbers of patients who had been exposed to toxic agents during the Iran-Iraq war (1981-1988). In the aftermath of the conflict, he established a clinic for those suffering from the delayed and long-term effects of exposure to chemical warfare agents. Dr Balali-Mood was one of the contributors to the Practical Guidebook on the Medical Management of Chemical Casualties.

The second awardee, Dr Alastair Hay of the United Kingdom of Great Britain and Northern Ireland has taken part in several missions to investigate and analyse samples following the use of toxic agents as weapons. His training courses for doctors and OPCW inspectors working in Syria have aided them the achieve a better understanding of the long-term health effects of exposure to chemical weapons and establishing more effective protocols for the treatment of victims.

Dr Hay donated his cash prize to the OPCW voluntary trust fund for victims of chemical weapons.

Memorials

The OPCW’s physical space incorporates tangible reminders about the victims of chemical weapons.

In the garden surrounding the Organisation’s Headquarters stands the Memorial to the Victims of Chemical Weapons. This statue is dedicated to the “memory of the victims of chemical weapons”. Depicted is a victim whose dying body transforms into doves of peace. This memorial was presented to the OPCW by the Government of Iran in 2012.

The nearby Halabja Memorial commemorates the victims of the chemical weapons attack that took place on 16 March 1988 on the town Halabja in Iraq. Many people lost their lives, among them women and children. Survivors have suffered severe long-term damage to their health. The memorial was presented to the OPCW by the Government of Iraq in 2014.

Outside the OPCW’s perimeter is a living monument consisting of a maple tree situated in a dune landscape with granite paving etched with a poem to chemical weapon victims. The memorial was unveiled in 1997 by Her Majesty Beatrix, The Queen of the Netherlands, on the occasion of the OPCW’s 10th anniversary.

Membership

States Parties to the Convention: 193

Signatory States: 1

Non-signatory States: 3

Convention Entry Into Force (EIF)

29 April 1997

The Secretariat  of  Organisation for the Prohibition of Chemical Weapons

Johan de Wittlaan 32

2517 JR The Hague

The Netherlands

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