Basic Facts on Chemical Disarmament


Brief History of the Treaty

The Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction (otherwise known as the Chemical Weapons Convention or CWC) was opened for signature with a ceremony in Paris on 13 January 1993—130 States signed the Convention within the first two days. Four years later, in April 1997, the Convention entered into force with 87 States Parties—the ratification of the Convention by at least 65 States, achieved in November 1996, was a precondition to trigger the 180-day countdown until the Convention’s entry into force. Currently, the CWC comprises 184 States Parties, as well as a fully functioning implementing Organisation, the Organisation for the Prohibition of Chemical Weapons (OPCW).

The Convention had been the subject of nearly 20 years of negotiations within the Conference on Disarmament in Geneva. The States involved in these negotiations were seeking to finalize an international treaty banning chemical weapons, and designed to ensure their worldwide elimination. This goal was indeed achieved.

The Convention is unique because it is the first multilateral treaty to ban an entire category of weapons of mass destruction (WMD) and to provide for the international verification of the destruction of these weapons. Furthermore, it is the first disarmament treaty negotiated within an entirely multilateral framework, leading to increased transparency and its application equally to all States Parties. The Convention was also negotiated with the active participation of the global chemical industry, thus ensuring industry’s ongoing cooperation with the CWC’s industrial verification regime. The Convention mandates the inspection of industrial facilities to ensure that toxic chemicals are used exclusively for purposes not prohibited by the Convention.

Altogether, the international community succeeded in producing a treaty that would verify the destruction of chemical weapons worldwide as well as ensure the non-proliferation of these weapons and the toxic chemicals used in their manufacture. The Convention also encourages international cooperation between States Parties in the peaceful uses of chemistry, and provides for assistance and protection to States Parties that are threatened or attacked by chemical weapons.

Before the Convention is considered in greater detail, it is useful to understand why such a treaty was necessary. Where does the threat from chemical weapons come from?

To top

Brief History of Chemical Weapons Use

Although chemicals had been used as tools of war for thousands of years—e.g. poisoned arrows, boiling tar, arsenic smoke and noxious fumes, etc.—modern chemical warfare has its genesis on the battlefields of World War I.

During World War I, chlorine and phosgene gases were released from canisters on the battlefield and dispersed by the wind. These chemicals were manufactured in large quantities by the turn of the century and were deployed as weapons during the protracted period of trench warfare. The first large-scale attack with chlorine gas occurred 22 April 1915 at Ieper in Belgium. The use of several different types of chemical weapons, including mustard gas (yperite), resulted in 90,000 deaths and over one million casualties during the war. Those injured in chemical warfare suffered from the effects for the rest of their lives; thus the events at Ieper during World War I scarred a generation. By the end of World War I, 124,000 tonnes of chemical agent had been expended. The means of delivery for chemical agent evolved over the first half of the twentieth century, increasing these weapons’ already frightening capacity to kill and maim through the development of chemical munitions in the form of artillery shells, mortar projectiles, aerial bombs, spray tanks and landmines.

After witnessing the effects of such weapons in World War I, it appeared that few countries wanted to be the first to introduce even deadlier chemical weapons onto the World War II battlefields. However, preparations were made by many countries to retaliate in kind should chemical weapons be used in warfare. Chemical weapons were deployed on a large scale in almost all theatres in the First and Second World Wars, leaving behind a legacy of old and abandoned chemical weapons, which still presents a problem for many countries.

During the Cold War, the United States and the Soviet Union both maintained enormous stockpiles of chemical weapons, amounting to tens of thousands of tonnes. The amount of chemical weapons held by these two countries was enough to destroy much of the human and animal life on Earth.

Iraq used chemical weapons in Iran during the war in the 1980s, and Iraq also used mustard gas and nerve agents against Kurdish residents of Halabja, in Northern Iraq, in 1988. The horrific pictures of Halabja victims shocked the world at the time of the negotiations in Geneva on the Chemical Weapons Convention. The two most recent examples of the use of chemical weapons were the sarin poisoning incident in Matsumoto, a Japanese residential community, in 1994, and the sarin attack on the Tokyo subway in 1995, both perpetrated by the Aum Shinrikyu doomsday cult. These two attacks re-focussed international attention on the potential use of chemical weapons by terrorists, and on the dangers posed by chemical weapons.

The devastating impact chemical weapons have had in the past, and the potential for the use of modern—even more deadly—chemical agents not only by States at war but in other violent conflicts and by non-State actors, provide the imperative for the international effort to uphold the ban on such weapons and to work towards the complete, global elimination of chemical weapons.

To top

Brief Description of Chemical Weapons

The general and traditional definition of a chemical weapon is a toxic chemical contained in a delivery system, such as a bomb or shell.

The Convention defines chemical weapons much more generally. The term chemical weapon is applied to any toxic chemical or its precursor that can cause death, injury, temporary incapacitation or sensory irritation through its chemical action. Munitions or other delivery devices designed to deliver chemical weapons, whether filled or unfilled, are also considered weapons themselves.

The toxic chemicals that have been used as chemical weapons, or have been developed for use as chemical weapons, can be categorised as choking, blister, blood, or nerve agents. The most well known agents are as follows: choking agents—chlorine and phosgene, blister agents (or vesicants)—mustard and lewisite, blood agents—hydrogen cyanide, nerve agents—sarin, soman, VX.

Of course some toxic chemicals, and/or their precursors, are utilised globally in industry. For example, toxic chemicals are employed as basic raw material, or as anti-neoplastic agents, which prevent the multiplication of cells, or as fumigants, herbicides or insecticides. Such chemicals are considered chemical weapons if they are produced and stockpiled in amounts that exceed requirements for those purposes that are not prohibited under the Convention.

The Convention is designed to ensure that toxic chemicals are only developed and produced for purposes unrelated to chemical weapons. Chemical technology must not be misused, and the OPCW has a mandate to monitor chemical industry to make certain that this is the case. To aid the OPCW in this task, the Convention divides toxic chemicals and precursors that could be used as chemical weapons or that could be used in the manufacture of chemical weapons into three Schedules. Schedule 1 chemicals have been used as chemical weapons in the past and/or have very few or no peaceful uses, and thus pose the most direct threat to the Convention. Schedule 2 chemicals are primarily precursors to Schedule 1 chemicals and most have some industrial uses. Schedule 3 chemicals are produced in large quantities commercially but in some cases were used as chemical warfare agents and can also serve as precursors to Schedule 1 or 2 chemicals. Production facilities of many organic chemicals termed discrete organic chemicals are also subject to declaration requirements and verification activities.

To help facilitate the destruction and verification process, chemical weapons are formally divided into three Categories. Into Category 1 fall Schedule 1 chemical agents and munitions filled with Schedule 1 agents. Category 2 covers munitions filled with other toxic chemicals and any other weaponised chemical agents—other than those in Schedule 1. Unfilled munitions and devices, and any other equipment specifically designed to aid in the deployment of chemical weapons, fall into Category 3. Destruction timelines are set by the Convention for the destruction of all three Categories of chemical weapons.

The following sections describe in more detail the international efforts made in the area of chemical disarmament since the seventeenth century, the structure and purview of the CWC, the structure and function of the OPCW, and the implementation of the CWC since 1997.

To top

Nerve agents

“Nerve agents”, or “nerve gases”, as they are sometimes called, are some of the most well known chemical weapons. They derive their name from their mode of action on the human body. They are organophosphorus compounds and are divided into two distinct chemical families, the “G-agents” (tabun, sarin, soman, etc.) and the “V-agents” (VA, VG, VX, etc.). Although chemically different, G- and V-agents have the same effect.

Electrical signals are transmitted to and from the brain to the various parts of the body via the nerve cells (neurons). At the junction (synapse) between two nerve cells there is a gap. To enable an electrical impulse to cross this gap, the nerve cells spontaneously generate a chemical transmitter. There are several such transmitters in different parts of the nervous system, one of which is acetylcholine. Once the electrical signal has crossed the gap, the acetylcholine is immediately hydrolyzed through catalysis by the enzyme acetylcholinesterase. Nerve agents function by inhibiting this enzyme and thus preventing it from breaking down the acetylcholine. The result is the rapid paralysis of the nerve cells throughout the body. If left untreated, such paralysis is quickly followed by death.

Nerve agents can be dispersed as liquids or in aerosol form, allowing them to be inhaled or absorbed through the skin. All nerve agents are extremely toxic. For example, just one drop of VX the size of a pinhead absorbed through the skin will be more than enough to cause death.

To top

History of Chemical Disarmament

For as long as chemicals have been used as a means of warfare, efforts to curtail such use have been undertaken internationally. The first international agreement limiting the use of chemical weapons dates back to 1675, when France and Germany came to an agreement, signed in Strasbourg, prohibiting the use of poison bullets.

Almost exactly 200 years later, in 1874, the next treaty or agreement of this sort was concluded: the Brussels Convention on the Law and Customs of War. The Brussels Convention prohibited the employment of poison or poisoned weapons, and the use of arms, projectiles or material to cause unnecessary suffering. Before the turn of the century, a third agreement came into being; an international peace conference held in The Hague in 1899 led to the signing of an agreement that prohibited the use of projectiles filled with poison gas.

In the wake of World War I, during which the world witnessed the horrors of large-scale chemical warfare, international efforts to ban the use of chemical weapons and prevent such suffering from being inflicted again, on soldiers and civilians, intensified. The result of this renewed global commitment was the 1925 Geneva Protocol for the Prohibition of the Use of Asphyxiating, Poisonous or Other Gases, and Bacteriological Methods of Warfare. The Geneva Protocol does not, however, prohibit the development, production or possession of chemical weapons. It only bans the use of chemical and bacteriological (biological) weapons in war. Furthermore, many countries signed the Protocol with reservations permitting them to use chemical weapons against countries that had not joined the Protocol or to respond in kind if attacked with chemical weapons. Since the Geneva Protocol has been in force, some of these States Parties have dropped their reservations and accepted an absolute ban on the use of chemical and biological weapons.

In 1971 the Eighteen Nations Disarmament Committee (ENDC) (later to become the Conference on Disarmament)completed negotiations on the text of the Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons, commonly referred to as the Biological Weapons Convention or BWC. In conjunction with the 1925 Geneva Protocol, it banned its States Parties from developing, producing, or possessing biological weapons, but contained no mechanism to verify the compliance of States Parties with these prohibitions. Included within the BWC was the stipulation that countries commit themselves to the negotiation of an international treaty banning chemical weapons.

Beginning in 1986, the global chemical industry actively participated in these negotiations.

Unlike the BWC, the negotiators of a chemical weapons ban reached an understanding that this ban would be subject to international verification. To this end, trial inspections of both industrial and military facilities were undertaken, starting in late 1988.

On 3 September 1992 the ad hoc committee submitted to the Conference on Disarmament the agreed text of the Convention on the Prohibition of the Development, Production, Stockpiling, and Use of Chemical Weapons, and on Their Destruction, now commonly referred to as the Chemical Weapons Convention or CWC. The Chemical Weapons Convention was opened for signature in Paris on 13 January 1993 and it was subsequently deposited with the United Nations Secretary-General in New York.

According to the terms of the Convention, the CWC would enter into force 180 days after the 65th country ratified the treaty. To prepare for the treaty’s entry into force and the implementation of the verification regime, a Preparatory Commission (PrepCom) was established in 1993. Its mission was to lay the groundwork for the establishment of the permanent implementing body for the CWC: the Organisation for the Prohibition of Chemical Weapons or OPCW. The PrepCom was housed in The Hague, which became the host city of the OPCW as well. In addition to preparing the Convention’s implementation guidance, another of the PrepCom’s most important tasks was training 200 inspectors to conduct inspections worldwide of both military and industrial sites in order to verify compliance with the Convention.

Hungary was the 65th country to ratify the Convention, in late 1996, and on 29 April 1997 the Chemical Weapons Convention entered into force with 87 States Parties—becoming binding international law. (An additional 22 countries had ratified the treaty in the 180 days between Hungary’s ratification and entry into force.)

With the entry into force of the Convention, the OPCW immediately began its work to implement the Convention. Both the Convention and its implementing body are intended to adapt not only to shifts in the international environment and the changing needs of States Parties, but also to respond to the rapid pace of scientific and technological developments.

Every five years, the Convention foresees that the States Parties should undertake a review of the implementation process. These review conferences serve as fora for the assessment and evaluation of the CWC’s implementation, and the identification of areas where change is needed. A particular focus is given to the verification regime and the changing context within which it is implemented as well as scientific and technological advances in chemistry, engineering and biotechnology. The first review conference was held from 28 April to 9 May 2003.

To top

Chemical Weapons: Major Developments in Their Use and Prohibition

1675 The Strasbourg Agreement The first international agreement limiting the use of chemical weapons, in this case, poison bullets.
1874 The Brussels Convention on the Law and Customs of War The Brussels Convention prohibited the employment of poison or poisoned weapons, and the use of arms, projectiles or material to cause unnecessary suffering.
1899/1907 Hague Peace Conferences Bans on use of poisoned weapons, ‘asphyxiating or deleterious gases’.
1915-1918 Europe, World War I 1.3 million casualties, 90,000 fatalities from chemical weapons; first large-scale use of CW, Ieper, Belgium.
1925 Geneva Protocol Ban on CW use; but no prohibition on development, etc. - some states interpret as “no first use” - 132 parties by 2000.
1972 Biological and Toxin Weapons Convention Comprehensive BW prohibition - 143 parties, 17 signatories by 2000; but no verification mechanism; commitment to negotiate on CW.
1980's Iran-Iraq War Including use by Iraq of CW agents against its own civilian population, Halabja, 1988
1993 Chemical Weapons Convention Signing of CWC in Paris, January; Comprehensive bans on development, production, stockpiling and use of CW, with destruction timelines; Preparatory Commission for OPCW established.
1997 OPCW, The Hague The Chemical Weapons Convention enters into force for 87 States Parties; The OPCW commences its operations in The Hague; as of June 1997, inspections begin.
2007 Tenth Anniversary of the OPCW 182 Member States. 25,000 metric tons of chemical weapons (35% of the declared stockpiles worldwide) have been certified by the OPCW as destroyed. 3,000 inspections have been carried out by OPCW inspection teams at approximately 1,100 military and industrial sites in 80 countries.

To top

The CWC and the OPCW

To top

Organisation for the Prohibition of Chemical Weapons

Article VIII of the Convention establishes the OPCW as the implementing body of the Chemical Weapons Convention. The OPCW is given a mandate, “ . . . to achieve the object and purpose of [the] Convention, to ensure the implementation of its provisions, including those for international verification of compliance with it, and to provide a forum for consultation and cooperation among States Parties.”

The Technical Secretariat of the OPCW is responsible for the day-to-day administration and implementation of the Convention, including inspections, while the Executive Council and the Conference of the States Parties are decision-making organs designed primarily to determine questions of policy and resolve matters arising between the States Parties on technical issues or on interpretations of the Convention. The chairs of the Executive Council and the Conference are appointed by each body’s membership. The Technical Secretariat is headed by a Director-General, who is appointed by the Conference on the recommendation of the Council.

The Convention also provides for the establishment of three subsidiary bodies to aid the three main organs of the OPCW in their work: the Scientific Advisory Board, the Advisory Body on Administrative and Financial Issues, and the Confidentiality Commission.

The Scientific Advisory Board (SAB) is a group composed of independent experts who are mandated to assess relevant scientific and technological developments and report on such subjects to the Director-General. The SAB also provides expert advice on any proposed changes to the Schedules of Chemicals and any other advice that might be required, including in relation to subjects such as verification methodologies and equipment.

As a subsidiary organ of the Conference of the States Parties, the main function of the Confidentiality Commission is to settle any disputes between States Parties related to confidentiality.

The Advisory Body on Administrative and Financial Issues (ABAF) meets regularly to advise both the Technical Secretariat and the States Parties on issues relating to the OPCW programme and budgets. The ABAF reviews draft budgets prepared by the Technical Secretariat before they are submitted to the Council and the Conference for approval.

To top

Implementing the Regime

Responsibilities of the States Parties

The CWC cannot be successfully implemented without the constant and diligent work of the OPCW Member States.

Upon becoming a party to the Convention, each State has to undertake a variety of internal measures in order to comply with the Convention and to enable the verification mechanism to function properly. Given the complexity of the treaty, this is not an easy task. The internal measures range from preparing and conducting the destruction of chemical weapons arsenals, to surveying and regulating chemical industries, to amending a number of domestic laws and administrative rules.

The first obligation a State Party must fulfil, at the time the CWC enters into force for it, is the establishment and notification of its National Authority to serve as the national focal point for effective liaison with the OPCW and other States Parties. The main tasks of the National Authority include the coordination of the submission of declarations to the Organisation, as well as the monitoring of national trade in scheduled chemicals and the oversight of any chemical weapons destruction programme. Working with other branches of the national government or legislature on the drafting and enactment of proper implementing legislation, which codifies the CWC and its prohibitions/obligations into national law, may be another responsibility of a National Authority.

A major early obligation is the requirement to submit an initial declaration, not later than 30 days after the treaty enters into force for a given State. Other required notifications, due within 30 days, include: points of entry, standing diplomatic clearance numbers for non-scheduled aircraft, and the issuance of two-year multiple-entry visas, all to facilitate the conduct of inspections. The initial declaration serves as a declaration of any past or present chemical weapons programmes pursued by a State Party, as well as declaring the presence of any old and/or abandoned chemical weapons on its territory, or which it has abandoned on the territory of another State. Destruction of all such chemical weapons must be completed within ten years from the entry into force of the Convention, by 2007. Any CWPFs declared by a State Party must be closed down within 90 days of the Convention entering into force for that State Party and the destruction of such facilities must also be completed by 2007. These former production facilities, following their inactivation, must be destroyed or converted to peaceful purposes. The Convention provides for the possibility of a one-time, five year extension of final destruction deadlines for chemical weapons stockpiles up to 2012. A request for extension must be made to the Executive Council and approved by the Conference of the States Parties. In special circumstances and upon approval by the other Member States, chemical production facilities may be converted for use for peaceful purposes.

An initial declaration under Article VI, or industry declaration, detailing any facilities in a State Party producing, in some cases producing or consuming, Scheduled chemicals above certain thresholds, must also be submitted to the Technical Secretariat within 30 days of the Convention entering into force for any State Party. The States Parties with chemical industry engaged in such activities must submit annual declarations on past and anticipated industrial activities and the export/import of Scheduled chemicals. States Parties with chemical weapons destruction programmes must also submit annual declarations relating to the implementation of such programmes.

To top

Destruction / Conversion

The most important obligation under the Convention is the destruction of chemical weapons. It is also the most expensive aspect of the Convention’s implementation.

Most of the destruction costs are generated by the investment in state-of-the-art technology to ensure that the risk to people and to the environment is kept to a minimum at every stage in the transportation and destruction of munitions, as well as during the removal and destruction of chemical agents. Destruction, therefore, has to be carried out at highly specialised facilities.

There are two main technological approaches to the destruction of chemical agents: the direct incineration of the agents and neutralisation by means of various chemical reactions. Research to develop other methods is continuing. It is up to each State Party to determine which destruction method it wishes to use, provided that it meets strict environmental standards, that the destruction is complete and irreversible, and that the design of the facility allows for adequate verification. It is important that the exploration of alternative technologies for the demilitarisation and destruction of chemical weapons continues in order to develop processes that are both cost effective and environmentally responsible.

The States Parties must submit detailed plans to the Technical Secretariat that set out the process to be used in the destruction activities and the timelines to be followed. These plans must be submitted for each chemical weapons destruction facility (CWDF)—where the chemical weapons are being destroyed—and for each CWPF that is to be destroyed as well. If a CWPF is to be converted, detailed plans of the conversion process must also be submitted. The plans for destruction and/or conversion are placed before the Executive Council for approval. If approval is not forthcoming, then destruction may commence under continuous monitoring by OPCW inspectors.

The destruction of old and/or abandoned chemical weapons is especially difficult and potentially dangerous. Old and/or abandoned chemical munitions have often become less stable with time and there is a greater risk of an explosive detonation or agent contamination. The destruction of such weapons is being undertaken in a small number of States Parties, as a matter of urgency. Thousands of tonnes of chemical agents and munitions were dumped in the North Sea and the Baltic Sea, as well as other bodies of water worldwide, in the years immediately following World War II. These weapons are not covered by the Convention, which requires only that chemical weapons dumped at sea after 1 January 1985 be declared to the OPCW.

To top


The States Parties regulate the use of Scheduled chemicals by industry within their borders, and prepare industry to receive regular OPCW inspections designed to verify that Scheduled chemicals and “discrete organic chemicals” (DOC) are being utilised solely for peaceful purposes.

Under the terms of the Convention, the transfer of Schedule 1 chemicals is strictly controlled among Member States—only for research, medical, pharmaceutical or protective purposes, and in limited quantities—and is forbidden to States not Party. A similar ban on the transfer of Schedule 2 chemicals to States not Party came into force in April 2000. Free trade in Schedule 2 chemicals is permitted among States Parties. It is permitted to transfer Schedule 3 chemicals to both States Parties and States not Party; however, a recipient State not Party must produce an end-user certificate, which ensures that the chemicals are being used for peaceful purposes. The Convention does foresee that States Parties may consider other measures regarding the transfer of Schedule 3 chemicals to States not Party five years after the Convention enters into force.

In addition to the requirements for end-user certificates for transfers of Schedule 3 chemicals, the States Parties are required to monitor carefully exports and imports of all Scheduled chemicals and report this information to the Technical Secretariat on an annual basis.

To top

OPCW Verification

The central role of the Technical Secretariat in CWC implementation is verification.

The Convention and its Verification Annex mandate that the Technical Secretariat verify not only the destruction of chemical weapons stockpiles and CWPFs, but also that Scheduled chemicals are being used solely for permitted purposes. The OPCW Inspectorate, a group of specially trained inspectors within the Technical Secretariat, carries out inspections of military and industrial sites.

Teams of OPCW inspectors conduct verification activities worldwide, and in some cases on a continuous basis. The verification process is conducted in an objective and transparent manner; all States Parties are treated equitably and due respect is given to each State Party’s national security.

The size of an inspection team varies considerably depending on the type of facility being inspected and on the type of inspection. The composition of each team also varies according to the type of facility. A team sent to verify the destruction of chemical weapons, for example, may require specialists with expertise in fields such as chemical weapons and munitions technology, chemical production technology, analytical chemistry, and health and safety. On the other hand, a team sent to inspect a chemical industry facility may consist of specialists in the fields of chemical production technology, industrial chemistry, chemical production logistics, and analytical chemistry.

If circumstances at the inspection site do not permit the analysis of samples, the samples can be sent off site to specially designated laboratories for analysis. To acquire the status of a designated OPCW laboratory, a laboratory in a State Party must achieve a high level of performance in several OPCW proficiency tests, and participate in testing regularly to maintain this standard. If a sample must be sent for off-site analysis, stringent procedures will be followed to guarantee the chain of custody, to avoid tampering and to ensure the anonymity of the sample.

Three types of inspections or investigations are foreseen under the Convention: routine inspections, challenge inspections and investigations of alleged use.

Routine inspections are conducted at declared chemical weapons storage, production and destruction facilities (CWSFs, CWPFs, and CWDFs), as well as at declared industrial facilities that produce, process or consume in certain cases chemicals listed in the three Schedules to the Convention, or that produce the unscheduled discrete organic chemicals (DOCs), in quantities above specified thresholds. These inspections are designed to verify the accuracy of information declared by States Parties in their initial and annual declarations, and that the activities of the States Parties are in accordance with the Convention.

Challenge inspections are provided for under the Convention, which grants each State Party the right to request the Director-General to undertake at short notice an OPCW inspection on the territory of any State Party, or at any location under the jurisdiction or control of any other State Party, in order to clarify and resolve any questions of possible non-compliance.

An investigation of alleged use can be conducted by the OPCW at the request of a State Party, either to confirm the actual use or threat of use of chemical weapons, or to assess the need for assistance, or both.

During all OPCW verification activities—the receipt and processing of declarations and destruction/conversion plans and on-site inspections and monitoring—stringent compliance with the OPCW confidentiality regime is maintained. The Technical Secretariat safeguards all official information in its possession in accordance with strict security regulations. The classified information submitted by the States Parties, as well as classified documents generated by the Secretariat in relation to the implementation of the verification regime, are handled electronically on a Security Critical Network, to which access is highly restricted.

To top

Implementation Support

The Convention requires complex reporting and regulatory arrangements to be established at the national level. Moreover, each State Party must inform the Organisation of the legislative and administrative measures put in place to implement the Convention. Without the proper national controls, the Convention’s object and purpose in such key areas as non-proliferation cannot be achieved in a reliable manner.

The Convention recognises that in complying with these important obligations, States Parties may require assistance from the Organisation. The Secretariat provides technical assistance and technical evaluation to States Parties in the implementation of the provisions of the Convention.

Current implementation support programmes include: legal technical assistance, National Authority training courses, the Annual National Authority Meeting, regional National Authority meetings, thematic workshops on priority implementation issues, national technical assistance visits and seminars, networks of experts, National Authority information packages, electronic tools for National Authorities to support CWC declarations in a common electronic format, National Authority web pages and other relevant information/material on the OPCW web site (

To top

Legislative Assistance

In order to ensure the passage of effective implementing legislation—legislation that enacts all of the Convention’s provisions, making them an integral part of each State Party’s national law—the Technical Secretariat and the Member States work together to provide legal assistance to States Parties or States not Party preparing to join the Convention that might require support in this area.

To top

International Cooperation

The fostering of international cooperation for the implementation of the Convention and the promotion of the peaceful uses of chemistry is one of the Convention’s mandates. After the entry into force of the Convention, the OPCW initiated a wide range of programmes intended to assist States Parties in building their technical and scientific capacities in the field of the peaceful use of chemistry. Assistance is being provided to publicly funded laboratories to improve their technical capabilities. Research projects in relevant fields of chemistry are supported or co-sponsored by the OPCW. The OPCW also operates an information service for companies, individuals and officials from developing countries. This cost-free service provides information on substitutions for toxic materials, on safety and health data for toxic chemicals, and on issues that relate to the implementation of the Convention or to its implications for certain types of commercial enterprise in the chemical industry. The OPCW also provides an annual training course, the Associate Programme, for chemists and chemical engineers from Member States whose economies are in development or in transition. The Associate Programme provides theoretical and practical experience in the implementation of the Convention, as well as training at modern chemical industrial facilities.

To top

Assistance and Protection

Under Article X of the Convention, each State Party has the right to request, and receive from the OPCW, assistance and protection if:

  • Chemical weapons have been used against it;
  • Riot control agents have been used against it as a method of warfare; or,
  • It is threatened by actions or activities of any State that are prohibited for States Parties by Article I of the Convention.

States Parties are required by the Convention to inform the OPCW of any national protective programmes and to contribute to the protective capabilities of the OPCW, including by making contributions of equipment and/or personnel, or by contributing funds to the Voluntary Fund for Assistance.

The OPCW has made preparations to respond and act on an emergency basis should the Organisation be required to do so. These preparations include coordinating and mobilising international mechanisms to respond to requests for assistance and establishing a cooperative response structure to handle requests for assistance and protection against chemical weapons.

The OPCW provides training courses and coordination seminars and workshops throughout the year that help to prepare the Technical Secretariat and the States Parties to protect civilian populations from chemical attack, and to respond with adequate assistance and protection on an emergency basis.

To top


Universal adherence to the CWC, or universality, is a fundamental goal of the OPCW. If the Convention is to fulfil its mandate “to exclude completely the possibility of the use of chemical weapons”, universality is crucial.

The universality of the Convention would help not only to establish further the global norm against chemical weapons, but it would also provide a basis for global efforts to eliminate potential safe havens for any individual or group, including terrorists, who would seek to develop and/or use chemical weapons in violation of the Convention.

To top


Chemical weapons, including old chemical weapons, abandoned by a State after 1 January 1925 on the territory of another State without the consent of the latter.
Working group established by the Conference on Disarmament in 1980 to negotiate the text of a convention banning chemical weapons.
A subsidiary body of the OPCW that advises the Technical Secretariat and the States Parties on administrative and financial issues.
Technology for the destruction of chemical weapons that provides an alternative to incineration or chemical neutralisation, which will have less of an impact on the environment.
One of three annexes to the CWC; contains the Schedules of Chemicals and the criteria for inclusion of chemicals in schedules.
Member States of the OPCW are required to make annual declarations to the OPCW detailing any activities undertaken with regard to the destruction of chemical weapons, the destruction or conversion of CWPFs, past and anticipated production, and in some cases processing and consumption of Scheduled chemicals, in some cases the production sites of discrete organic chemicals, as well as the export and import of Scheduled chemicals by chemical industry.
Under Article X, the CWC provides for assistance and protection to States Parties that are threatened or attacked with chemical weapons.
A weapon containing two or more chemical components, each of which is relatively non-toxic separately, but which, when allowed to mix in a bomb or shell, produce a highly toxic substance.
1975 Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons; entered into force in 1975 and banned biological weapons in their entirety, yet contained no verification mechanism.
A chemical agent that affects the skin and in particular moist areas of the body such as the eyes and membranes in the respiratory and digestive systems.
A class of chemical weapons that are dispersed as gases absorbed through the lungs; they affect the ability of blood cells to utilise oxygen, starving and eventually stopping the heart.
1874 treaty prohibiting the use of poison or poisoned weapons in war.
For purposes of declarations, chemical weapons buried after 1 January 1977 or chemical weapons buried before 1 January 1977 that are uncovered.
An incapacitating psychotomimetic agent (related to LSD) developed during the 1950s that affects the central nervous system and mental acuity.
A universal system of numbering and naming that is used to identify chemicals and specific chemical mixtures.
The Verification Annex of the CWC divides chemical weapons into three categories for purposes of destruction: Category 1, Category 2, and Category 3. All Category 2 and 3 chemical weapons had to be destroyed by April 2002; Category 1 chemical weapons must be destroyed by April 2007.
An inspection triggered by a suspected violation of a treaty or agreement; with respect to the CWC: the inspection, conducted on short-notice, of any facility or location in a State Party (or controlled by a State Party) requested by another State Party on the suspicion of non-compliance with the convention.
A chemical substance that has the potential to cause physiological changes in humans and animals.
—unfilled munitions and devices, and equipment specifically designed for use directly in connection with employment of chemical weapons.
All toxic chemicals and their precursors, except when intended for those purposes foreseen by the Convention as not prohibited, as well as munitions and/or devices specifically designed to cause death, harm, temporary incapacitation or sensory irritation through the release of a toxic chemical, and any equipment specifically designed for use directly in connection with the employment of such munitions and devices.
A facility specially designed to destroy chemical weapons under the terms of the Convention; once such a facility has completed its destruction mandate, it must also be destroyed.
) Any equipment, as well as any building housing such equipment, that was designed, constructed or used at any time since 1 January 1946 in the production of chemicals including any Schedule 1 chemical or any other chemical that has no use above one tonne per year for non-prohibited purposes, but can be used for chemical weapons purposes. As well, any equipment used in the filling of munitions, submunitions, devices or bulk storage containers with Schedule 1 chemicals.
A facility designed to store chemical weapons stockpiles before they are destroyed, often co-located with a CWDF; the OPCW inspects such facilities regularly to ensure the non-diversion of the weapons stored there, which are a proliferation risk.
A choking agent that was one of the first toxic chemicals to be deployed on a battlefield.
A class of chemical weapons dispersed as a gas and absorbed though the lungs where they cause fluid to build up, choking the victim.
Main policymaking organ of the OPCW; composed of all member countries; meets annually, as well as in special session when necessary.
In March 1962, the Eighteen Nations Disarmament Committee was established. In 1969, it became the Conference of the Committee on Disarmament (CCD), following which, in 1983 it became the Conference on Disarmament with a mandate that covers all issues related to multilateral arms control and disarmament.
One of three annexes to the CWC; sets out the confidentiality regime to be followed by the OPCW when handling sensitive information—especially information related to the declarations made by States Parties—in order to protect the national security interests and commercial information of the States Parties.
One of the three subsidiary bodies of the OPCW; has a mandate to address any breaches of the OPCW confidentiality regime as well as undertake analysis of this regime and recommend any needed amendments.
The conversion of a chemical into another chemical via a chemical reaction.
24 hours a day, 7 days a week presence by OPCW inspectors at some CWDFs.
The CWC provides for the conversion of former CWPFs for peaceful use, upon the approval of the CSP and in circumstances when such action is merited due to the economic or industrial situation in a particular State Party.
Propanedinitrile [(2-chlorophenyl) methylene], also known as tear gas or pepper spray; often used as a riot control agent.
A laboratory that has gone through a process of proficiency testing and has been deemed by the OPCW to be competent for the receipt and analysis of samples taken during an inspection.
With respect to the CWC: the irreversible conversion of toxic chemicals into a form unsuitable for the production of chemical weapons and action upon munitions or other delivery devices that renders them unusable. The most common forms of destruction are incineration and neutralisation.
chemicals belonging to a class of chemical compounds consisting of all compounds of carbon except for its oxides, sulfides, and metal carbonates. Although DOCs are not included in the Schedules, plant sites producing DOCs are subject to the terms of the Convention if they produce more than 200 tonnes annually.
Schedule 2 nerve agent precursor commercially utilised as a flame retardant.
The term applied to a chemical or piece of equipment that has both peaceful and chemical weapons applications.
a document required in order to transfer Schedule 3 chemicals to a State not Party to the convention; this document ensures that the chemicals will be used for peaceful , non-prohibited, purposes.
The moment at which all provisions of a treaty are legally binding on its parties; for the CWC it was 180 days after ratification by the 65th State. For individual States Parties that ratify or accede to the Convention later, EIF comes 30 days after deposit of their respective instruments of ratification or accession.
The executive organ of the OPCW, responsible to the Conference; composed of representatives from 41 Member States, elected by the States Parties to serve two-year terms; meets 4-5 times per year in regular sessions and more frequently in meetings and informal consultations.
An arrangement between a State Party and the OPCW relating to a specific facility subject to on-site verification under Articles IV, V, or VI.
A family of nerve agents, including tabun, sarin, and soman.
for the Prohibition of the Use of Asphyxiating, Poisonous or Other Gases, and Bacteriological Methods of Warfare; 1925 agreement banning the use of chemical and biological weapons in war, but not their development or possession.
Kurdish village in northern Iraq that was the site of a 1988 mustard gas and nerve agent attack by the Iraqi government on its own citizens.
A chemical agent that is toxic to plants and that may be used to destroy unwanted vegetation.
A blood agent listed in Schedule 3; also used in the plastics industry.
Legislation enacted at the national level, which criminalises the prohibitions of the Convention and enables the prosecution of individuals for crimes committed with regard to chemical weapons; in many cases, implementing legislation is also necessary in order for a State Party to monitor effectively industry’s use of toxic chemicals.
A chemical agent that produces temporary physiological or psychological debilitation, thus rendering a human or animal incapable of functioning or performing normally.
The burning, under controlled, environmentally-responsible conditions, of chemical agent and/or munitions in order to achieve their irreversible destruction.
Declaration made by a State Party to the Technical Secretariat within 30 days of EIF of the CWC for that State Party detailing activities undertaken by that State Party with respect to chemical weapons, old or abandoned chemical weapons, CWPFs, riot control agents, and sea-dumped chemical weapons. This declaration should include plans to destroy any chemical weapons stockpiles and destroy or convert, where applicable, CWPFs. In addition, an industry declaration, made by States Parties within 30 days of EIF, detailing facilities on its territory or on territory under its control producing or, as appropriate, processing or consuming Scheduled Chemicals or DOCs, as well as any other imports/exports of toxic chemicals, is foreseen by the Convention.
A chemical agent that is toxic to insects and is used to control populations of insect pests.
The body within the Technical Secretariat responsible for the conduct of on-site inspections as well as challenge inspections and investigations of alleged use of chemical weapons.
Group established by the International Conference on Chemical Safety in Stockholm in April 1994; it is charged with the provision of policy guidance, advice, and recommendations to governments, international organisations, intergovernmental bodies, and NGOs on issues related to chemical safety and the sound management of chemicals.
The cooperative efforts of States Parties and the OPCW to promote the development of chemistry for peaceful uses, provide assistance and protection to States Parties in need, and assist in the global implementation of the convention.
Type of inspection that may be requested under Article IX to determine the use of chemical weapons and under Article X determine the need for assistance.
of binary or multicomponent chemical systems: the precursor that plays the most important role in determining the toxic properties of the final product and reacts rapidly with other chemicals in the binary or multicomponent system.
Help provided to States Parties by the Technical Secretariat or other States Parties in the drafting and enactment of implementing legislation which effectively integrates the Convention's prohibitions and obligations into national penal and civil law.
A measure of the impact of a toxic chemical on life processes (human, plant, or animal); the speed with which a toxic chemical inflicts death.
One of the more well-known blister agents, listed in Schedule 1.
A blister agent, Schedule 1, also referred to as H, HD, sulfur mustard, nitrogen mustard, or mustard gas; used widely during WWI.
The body established by a national government to liaise between the government and the Technical Secretariat for the purposes of CWC implementation; NAs serve many functions, including the coordination of inspections, monitoring the chemical industry, etc.
A highly toxic and potentially lethal organophosphorus compound that affects the nervous system by inhibiting the enzyme that aids the transmission of nerve impulses. Just one drop of a nerve agent absorbed through the skin can cause death. Nerve agents are divided into two chemical families: G-agents and V-agents.
A nerve agent dispersed as an aerosol, which can be inhaled or absorbed through the skin.
The irreversible conversion of a toxic chemical to a benign substance via a series of chemical reactions.
Prevention of the spread of tools of war and violence; with respect to the CWC: chemical weapons or the toxic chemicals and precursors used in their manufacture.
Individuals or groups that influence world events, either positively or negatively, without the backing or support of any sovereign government.
The Articles and Verification Annex require States Parties to the CWC to make certain notifications to the Technical Secretariat in order to facilitate implementation of the Convention: POEs, SDCNs, visas, the establishment of NAs, enactment of implementing legislation, the existence of national programmes for protection against chemical weapons, etc.
Chemical weapons that were produced before 1925 or chemical weapons produced in the period between 1925 and 1946 that have deteriorated to such an extent that they can no longer be used as chemical weapons.
The implementing body of the CWC established pursuant to Article VIII of the Convention; the OPCW is comprised of the Conference of the States Parties, the Executive Council, and the Technical Secretariat.
Facilities that produce DOCs/PSF above certain thresholds and thus are subject to declarations and inspections by OPCW inspectors under Article VI.
A colourless poisonous gas widely used as a chemical weapon during WWI, but which also has industrial utility in plastics manufacturing and is listed in Schedule 3.
The geographic location at which chemicals are produced, it may be comprised of numerous plants or factories and many buildings.
Locations designated by the State Party for the arrival and departure of OPCW inspection teams.
Any chemical reactant which takes part at any stage in the production of a toxic chemical, including any key component of a binary or multicomponent chemical system.
Body established after the CWC was opened for signature in 1993 to make the preparations for the entry into force of the Convention, the implementation of the verification regime, and the establishment of the OPCW.
A physical process-formulation, extraction and purification-during which a chemical is not converted into another chemical.
The formation of a chemical through a chemical reaction.
The annual quantitative potential for manufacturing a specific chemical based on the technological process actually used or planned to be used at the relevant facility.
A test regularly given by the Technical Secretariat in which laboratories in States Parties may participate in hopes of qualifying for designation—allowing them to receive samples for analysis.
The use of toxic chemicals or precursors in the development or production of chemical weapons, as prohibited under Article I of the CWC; the term also applies to the transfer or use of chemical weapons, preparations to use chemical weapons militarily, or assisting in the performance of these prohibited activities.
DOCs containing phosphorous, sulfur or fluorine; if a plant produces more than 30 tonnes of PSF chemicals annually, it is subject to declaration and verification under the CWC.
Formal step taken by a State to legally bind its government to a treaty.
Special sessions of the Conference of the States Parties, convened every five years to review the CWC’s implementation, particularly scientific and technological developments impacting the Convention, and recommend any necessary change.
Schedule 1 chemical that is also a valuable tool in medical and pharmaceutical research.
Any chemical not listed in a Schedule that can produce rapidly in humans sensory irritation or disabling physical effects that disappear within a short time following termination of exposure. These chemicals are often used by police or armed forces for crowd control.
An inspection of CWPFs, CWDFs, CWSFs or industrial facilities as foreseen under the Convention in the normal course of CWC implementation and/or in accordance with agreed detailed plans.
A colourless and odourless nerve agent, also known as GB. It was developed in 1939 and first produced industrially in 1944 It is a Schedule 1 chemical listed under the Schedules of Chemicals in the Annex on Chemicals of the Chemical Weapons Convention.
Schedule 1 chemical used in neurological research and testing kits for shellfish poisoning.
Toxic chemicals listed in the CWC's Schedules of Chemicals; Schedule 1 chemicals are the most dangerous and therefore the most controlled, and have few peaceful uses. The restrictions on those chemicals listed in Schedules 2 and 3 are fewer and these chemicals are often produced in large quantities for industrial purposes.
The Schedules of Chemicals, found in the Convention's Annex on Chemicals, lists toxic chemicals that have either been used as chemical weapons or are precursors to chemical weapons, and that may or may not be produced commercially. These chemicals, divided among three schedules, are controlled under the terms of the Convention.
Subsidiary body of the OPCW charged with the provision of advice on scientific and technological developments that impact the Convention, as well as other issues related to the CWC's scientific elements, such as changes to the Schedules.
States Parties must declare chemical weapons dumped at sea after 1 January 1985; they may declare weapons dumped earlier.
The electronic network at the Technical Secretariat where information submitted by States Parties in their declarations is stored; access to this network is highly restricted.
A State that signed the Chemical Weapons Convention prior to its entry into force in 1997 but has yet to deposit its instrument of ratification with the United Nations in New York.
A nerve agent also known as GD, which was first developed in 1944. It is a Schedule 1 chemical listed under the Schedules of Chemicals in the Annex on Chemicals of the Chemical Weapons Convention.
for non-scheduled aircraft; the issuance of this number by the States Parties to the Technical Secretariat facilitates the arrival of inspectors for inspections under Article IX-challenge inspections and investigations of alleged use-as well as the delivery of assistance and protection under Article X.
A State that has signed and ratified or acceded to the Chemical Weapons Convention and for which the initial 30-day period has passed (the CWC enters into force for a State only 30 days after its ratification or accession to the treaty).
The accumulation of chemical weapons (munitions or agents) as reserves.
City in France which was the site of the first international agreement to limit the use of chemical weapons in 1675.
The first of the nerve agents, also known as GA, developed in 1936 and produced industrially in 1942 It is a Schedule 1 chemical listed under the Schedules of Chemicals in the Annex on Chemicals of the Chemical Weapons Convention.
Main implementation organ of the OPCW, includes the Inspectorate and various support staff.
City in The Netherlands that serves as the seat of the Dutch government, as well as the host city for OPCW Headquarters; in 1899, The Hague was the site of an international peace conference that resulted in an agreement banning the use of poison gas in war.
A Schedule 2 chemical that is a precursor to mustard gas and is widely used in industry, for example in inks and dyes.
Any chemical that through its chemical action on life processes can cause death, temporary incapacitation or permanent harm to humans or animals.
The ability of a substance to cause a harmful effect.
A poison formed as a specific secretion product in the metabolism of a vegetable or animal organism as distinguished from inorganic poisons. Toxins can also be manufactured synthetically.
Schedule 3 chemical that is a precursor to nitrogen mustard gas, but is also a common industrial product, particularly in detergents, including shampoos.
The States Parties to the CWC are required under the Convention to provide such visas in order to enable inspections to take place without undue delay or cumbersome paperwork.
Adherence to the CWC (or any international treaty) by all 194 independent States in the world.
A group of stable nerve agents that are about ten times more toxic than sarin.
The process of using mechanisms such as satellites, seismic monitoring, or on-site inspections to collect data that demonstrates a State Party’s compliance with an agreement or treaty; verification of the Chemical Weapons Convention is undertaken by means of comprehensive declarations, data monitoring and on-site monitoring and inspections.
One of three annexes to the CWC; it sets out the verification regime to be implemented by the OPCW in order to verify the destruction of chemical weapons and non-proliferation of toxic chemicals and precursors. The VA provides for the inspection of CWPFs, CWDFs, CWSFs, and industrial facilities, producing or consuming Scheduled chemicals and DOCs above specified thresholds.
Account established under Article X of the CWC in order to provide funds, with which assistance and protection activities can be undertaken, if a request is received from a State Party or States Parties. States Parties may elect to make contributions to the Fund in lieu of other forms of donation to the assistance and protection programme (i.e. equipment or personnel).
The most common V-agent and one of the most toxic substances ever produced; it was first developed in the 1950s and produced industrially in 1961.
Nuclear, radiological, biological, or chemical weapons.

To top