Biological Weapons Convention

The Biological Weapons Convention (BWC), or Biological and Toxin Weapons Convention (BTWC), is a disarmament treaty that effectively bans biological and toxin weapons by prohibiting their development, production, acquisition, transfer, stockpiling and use. The treaty's full name is the Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on their Destruction. As of May 2025, 189 states have become party to the treaty.

The BWC is considered to have established a strong global norm against biological weapons. This norm is reflected in the treaty's preamble, which states that the use of biological weapons would be "repugnant to the conscience of mankind". It is also demonstrated by the fact that not a single state today declares to possess or seek biological weapons, or asserts that their use in war is legitimate. In light of the rapid advances in biotechnology, biodefense expert Daniel Gerstein has described the BWC as "the most important arms control treaty of the twenty-first century". However, the convention's effectiveness has been limited due to insufficient institutional support and the absence of any formal verification regime to monitor compliance. The treaty has seen notable violations in offensive biological weapons programs of the Soviet Union, international restrictions on biological warfare began only with the 1925 Geneva Protocol, which prohibits the use but not the possession or development of chemical and biological weapons. Upon ratification of the Geneva Protocol, several countries made reservations regarding its applicability and use in retaliation. Due to these reservations, it was in practice a "no-first-use" agreement only. In particular, it did not prevent multiple states from starting and scaling offensive biological weapons programs, including the United States (active from 1943 to 1969) and the Soviet Union (active from the 1920s until at least 1992).

thumb|The Council Chamber at the [[Palace of Nations in Geneva where the BWC was negotiated]]

The American biowarfare system was terminated in 1969 by President Nixon when he issued his Statement on Chemical and Biological Defense Policies and Programs. The statement ended, unconditionally, all U.S. offensive biological weapons programs. When Nixon ended the program the budget was $300 million annually.

The BWC sought to supplement the Geneva Protocol and was negotiated in the Conference of the Committee on Disarmament in Geneva from 1969 to 1972, following the conclusion of the negotiation of the Treaty on the Non-Proliferation of Nuclear Weapons. Of significance was a 1968 British proposal to separate consideration of chemical and biological weapons and to first negotiate a convention on biological weapons. The negotiations gained further momentum when the United States decided to unilaterally end its offensive biological weapons program in 1969 and support the British proposal. The final negotiation stage was reached when the United States and the Soviet Union submitted identical but separate drafts of the BWC text on 5 August 1971.]]

With only 15 articles, the BWC is relatively short. Over time, the treaty has been interpreted and supplemented by additional politically binding agreements and understandings reached by its States Parties at eight subsequent Review Conferences.

Summary of key articles

Article I: Never under any circumstances to develop, produce, stockpile, acquire, or retain biological weapons.
Article II: To destroy or divert to peaceful purposes biological weapons and associated resources prior to joining.
Article III: Not to transfer, or in any way assist, encourage, or induce anyone else to acquire or retain biological weapons.
Article IV: To take any national measures necessary to implement the provisions of the BWC domestically.
Article V: Undertaking to consult bilaterally and multilaterally and cooperate in solving any problems which may arise in relation to the objective, or in the application, of the BWC.
Article VI: Right to request the United Nations Security Council to investigate alleged breaches of the BWC and undertaking to cooperate in carrying out any investigation initiated by the Security Council.
Article VII: To assist States which have been exposed to danger as a result of a violation of the BWC.
Article X: Undertaking to facilitate, and have the right to participate in, the fullest possible exchange of equipment, materials and information for peaceful purposes.

The remaining articles concern the BWC's compatibility with the 1925 Geneva Protocol (Article VIII), negotiations to prohibit chemical weapons (Article IX), amendments (Article XI), Review Conferences (Article XII), duration (Article XIII, 1), withdrawal (Article XIII, 2), joining the convention, depositary governments, and conditions for entry into force (Article XIV, 1–5), and languages (Article XV).

Article I: Prohibition of biological weapons

Article I is the core of the BWC and requires each state "never in any circumstances to develop, produce, stockpile or otherwise acquire or retain:

microbial or other biological agents, or toxins whatever their origin or method of production, of types and in quantities that have no justification for prophylactic, protective or other peaceful purposes;
weapons, equipment or means of delivery designed to use such agents or toxins for hostile purposes or in armed conflict." This prohibition is known as the general-purpose criterion and is also used in Article II, 1 of the 1993 Chemical Weapons Convention (CWC). The general-purpose criterion covers all hostile uses of biological agents, including those developed in the future,

While it was initially unclear during the early negotiations of the BWC whether viruses would be regulated by it since they lie "at the edge of life"—they possess some but not all of the characteristics of life—viruses were defined as biological agents in 1969 and thus fall within the BWC's scope.

While Article I does not explicitly prohibit the "use" of biological weapons as it was already considered to be prohibited by the 1925 Geneva Protocol, it is still regarded as a violation of the BWC, as reaffirmed by the final document of the Fourth Review Conference in 1996. National implementing measures may take various forms, such as legislation, regulations, codes of conduct, and others. Which implementing measures are adequate for a state depends on several factors, including its legal system, its size and geography, the development of its biotechnology industry, and its participation in regional economic cooperation. Since no one set of measures fits all states, the implementation of specific obligations is left to States Parties' discretion, based on their assessment of what will best enable them to ensure compliance with the BWC.

A database of over 1,500 laws and regulations that States Parties have enacted to implement the BWC domestically is maintained by the non-governmental organization VERTIC. A similar database on national implementation measures developed by VERTIC and the United Nations Institute for Disarmament Research was launched in 2023. These concern the penal code, enforcement measures, import and export controls, biosafety and biosecurity measures, as well as domestic and international cooperation and assistance. A 2023 VERTIC report concluded that "gaps persist in States Parties' legal frameworks for implementing the Convention at the national level". The BWC's Implementation Support Unit issued a background information document on "strengthening national implementation" in 2018 and an update in 2019.

Article V: Consultation and cooperation

Article V requires States Parties to consult one another and cooperate in disputes concerning the purpose or implementation of the BWC. and the second in 2022 at the request of the Russian Federation.

Article VI: Complaint about an alleged BWC violation

Article VI allows States Parties to lodge a complaint with the United Nations Security Council if they suspect a breach of treaty obligations by another state. One formal complaint pursuant to Article VI has been lodged by the Russian Federation in 2022.

Article VII: Assistance after a BWC violation

Article VII obliges States Parties to provide assistance to states that so request it if the UN Security Council decides they have been exposed to danger as a result of a violation of the BWC. Despite no state ever having invoked Article VII, the article has drawn more attention in recent years, in part due to increasing evidence of terrorist organizations being interested in acquiring biological weapons and also following various naturally occurring epidemics.

Article X: Peaceful cooperation

Article X protects States Parties' right to exchange biological materials, technology, and information to be used for peaceful purposes.

Membership and joining the BWC

thumb|326x326px|Number of BWC States Parties from 1972 to 2020

The BWC has 189 States Parties as of May 2025, with Kiribati the most recent to become a party. Four states have signed but not ratified the treaty: Egypt, Haiti, Somalia, and Syria. Four additional states have neither signed nor acceded to the treaty: Chad, Djibouti, Eritrea and Israel.

The BWC's degree of universality remains low compared to other weapons of mass destruction regimes, including the Chemical Weapons Convention with 193 parties and the Treaty on the Non-Proliferation of Nuclear Weapons with 191 parties.

States can join the BWC through either ratification, accession or succession, in accordance with their national constitutional processes, which often require parliamentary approval. Ratification applies to states which had previously signed the treaty before it entered into force in 1975. The term originated in the proceedings to the Sixth Review Conference of the Biological and Toxins Weapons Convention held in Geneva in 2006. In the previous review, conference talks broke down over American refusals to allow for a verification mechanism be established to monitor biological weapons programs in states parties. This was against the wishes of other Western European and Others Group (WEOG) states, which also include Canada, Turkey, Australasia and Western Europe. At the 2006 Review Conference the JACKSNNZ states remain supportive of a verification protocol (although are unlikely to push for it knowing that the current US government will not accede on this point). However, the JACKSNNZ also seeks balance within the WEOG, and to protect the interests of non-EU states. Takeshi Aoki, director of the Bioweapons and Chemical Weapons Conventions Division of the Japanese Ministry of Foreign Affairs, said that JACKSNNZ is "neither a binding instrument, nor an exclusive one."

Verification and compliance

Confidence-building measures

thumb|324x324px|Number and percentage of BWC confidence-building measures submissions from 1987 to 2020

At the Second Review Conference in 1986, BWC States Parties agreed to strengthen the treaty by exchanging annual confidence-building measures (CBMs). These politically binding reports aim to prevent or reduce the occurrence of ambiguities, doubts and suspicions, and at improving international cooperation on peaceful biological activities.

Failed negotiation of a verification protocol

Unlike the chemical or nuclear weapons regimes, the BWC lacks both a system to verify states' compliance with the treaty and a separate international organization to support the convention's effective implementation. During four meetings in 1992 and 1993, VEREX considered 21 verification measures, including inspections of facilities, monitoring relevant publications, and other on-site and off-site measures. Another stimulus came from the successful negotiation of the Chemical Weapons Convention, which opened for signature in 1993. The Ad Hoc Group convened 24 sessions between 1995 and 2001, during which it negotiated a draft protocol to the BWC which would establish an international organization and introduce a verification system. However, at the 24th session of the Ad Hoc Group in July 2001 the George W. Bush administration rejected both the draft protocol circulated by the Group's Chairman and the entire approach on which the draft was based, resulting in the collapse of the negotiation process. Many analysts, including Matthew Meselson and Amy Smithson, criticized the U.S. decision as undermining international efforts against non-proliferation and as contradicting U.S. government rhetoric regarding the alleged biological weapons threat posed by Iraq and other U.S. adversaries.

In subsequent years, calls for restarting negotiations on a verification protocol have been repeatedly voiced. For instance, during the 2019 Meeting of Experts "several States Parties stressed the urgency of resuming multilateral negotiations aimed at concluding a non-discriminatory, legally-binding instrument dealing with (...) verification measures". However, since "some States Parties did not support the negotiation of a protocol to the BWC" it seems "neither realistic nor practicable to return to negotiations".

In December 2022, States Parties decided to establish a Working Group on strengthening the Convention, which aims to address among other issues, measures on verification and compliance.

Accusations of non-compliance

A number of BWC States Parties have been accused of breaching the convention's obligations by developing or producing biological weapons. Because of the intense secrecy around biological weapons programs, Around the time when the BWC negotiations were finalized, and the treaty was signed in the early 1970s, the Soviet Union significantly expanded its covert biological weapons program under the oversight of the "civilian" institution Biopreparat within the Soviet Ministry of Health. The Soviet program employed up to 65,000 people in several hundred facilities The Soviet authorities blamed the outbreak on the consumption of contaminated meat and for years denied any connection between the incident and biological weapons research. However, investigations concluded that the outbreak was caused by an accident at a nearby military microbiology facility, resulting in the escape of an aerosol of anthrax pathogen. Supporting this finding, Russian president Boris Yeltsin later admitted that "our military developments were the cause".

Western concerns about Soviet compliance with the BWC increased during the late 1980s and were supported by information provided by several defectors, including Vladimir Pasechnik and Ken Alibek. The agreement's objective was to uncover details about the Soviet's biological weapons program and to verify that all related activities had truly been terminated.

In February 2026, scientists at Porton Down discovered epibatidine in tissue samples taken from Alexei Navalny's body, and a joint statement was made by the foreign ministers of Britain, France, Germany, the Netherlands and Sweden that ″Moscow had the means, motive and opportunity to administer this poison to him″. British toxicology expert Alastair Hay said that if Russia was behind the poisoning, it would have broken the BWC treaty, as well as the Chemical Weapons Convention, which prohibits the use of such weapons.

Iraq

Starting around 1985 under Saddam Hussein's leadership, Iraq weaponized anthrax, botulinum toxin, aflatoxin, and other agents, and created delivery vehicles, including bombs, missile warheads, aerosol generators, and spray systems.

United States

In April 1997, Cuba invoked the provisions of Article V to request a formal consultative meeting to consider its allegations that the United States introduced the crop-eating insect Thrips palmi to Cuba via crop-spraying planes in October 1996. Cuba and the United States presented evidence for their diverging views on the incident in a formal consultation in August 1997. Having reviewed the evidence, twelve States Parties submitted reports, of which nine concluded that the evidence did not support the Cuban allegations, and two (China and Vietnam) maintained it was inconclusive.

A 2003 article published in Politics and the Life Sciences raised concerns about the compliance of the United States. Milton Leitenberg, James F. Leonard, and Richard Spertzel wrote that aspects of the U.S. biodefense program—particularly research conducted at the National Biodefense Analysis and Countermeasures Center—could be perceived as violating the BWC. The authors said that research on genetically modified pathogens, pathogen dispersal modeling, and "Red Teaming" activities, which simulate biothreat scenarios, resembled elements of past offensive biological weapons programs. The report questioned whether these activities, though carried out under the guise of defense, risked undermining the treaty’s prohibitions.

By Russia

In recent years, Russia has repeatedly alleged that the United States is supporting and operating biological weapons facilities in the Caucasus and Central Asia, in particular the Richard Lugar Center for Public Health Research in the Republic of Georgia. The U.S. Department of State called these allegations "groundless" and reaffirmed that "all U.S. activities (...) [were] consistent with the obligations set forth in the Biological Weapons Convention". Biological weapons expert Filippa Lentzos agreed that the Russian allegations are "unfounded" and commented that they are "part of a disinformation campaign". Similarly, Swedish biodefense specialists Roger Roffey and Anna-Karin Tunemalm called the allegations "a Russian propaganda tool".

During the Russian invasion of Ukraine, the Russian Federation convened a Formal Consultative Meeting under Article V of the Convention to address outstanding questions concerning the operation of biological laboratories in Ukraine by the United States. The meeting did not reach a consensus. The report concluded that North Korea "has an offensive biological weapons program and is in violation of its obligations under Articles I and II of the BWC" and that Iran "has not abandoned its (...) development of biological agents and toxins for offensive purposes". and does not compare with the institutions established to deal with chemical or nuclear weapons. For example, the Organisation for the Prohibition of Chemical Weapons (OPCW) has about 500 employees, the International Atomic Energy Agency employs around 2,600 people, and the CTBTO Preparatory Commission employs around 280 staff. In December 2022, as a result of the Ninth Review Conference, States Parties decided to establish one new full-time staff position within the ISU, only for the period from 2023 to 2027. The objective of these conferences is to ensure the effective realization of the convention's goals and, in accordance with Article XII, to "take into account any new scientific and technological developments relevant to the Convention". Most Review Conferences have adopted additional understandings or agreements that have interpreted or elaborated the meaning, scope, and implementation of BWC provisions.

{| class="wikitable"

! Review Conference

! Date

! Key outcomes and issues

! BWC States Parties

! Chairperson

! Final Document

|First

|3. – 21. March 1980

|1. Encouragement of voluntary declarations of (i) past possession of BWC-relevant items, (ii) efforts to destroy or divert these items to peaceful purposes, (iii) and enactment of national legislation to implement the convention.

2. Elaboration of the cooperation under Article X by including personnel training, information exchange, and the transfer of materials and equipment.

|87

|Ambassador Oscar Vaerno (Norway)

|BWC/CONF.I/10

|Second

|8. – 26. September 1986

|1. Agreement on the annual exchange of confidence-building measures (CBMs), including information on (i) high-containment research laboratories, (ii) abnormal infectious disease outbreaks, and (iii) the encouragement of BWC-relevant research in publicly available journals.

2. Bringing bioterrorism within the convention's scope by agreeing that it applies to all international, national and non-State actors and that it covers all relevant current and future scientific and technological developments.

3. Strengthening of Article V by agreeing on the Formal Consultative Process, a procedure to resolve doubts about compliance through consultative meetings.

4. Agreement that the World Health Organization would coordinate the emergency response in the event of suspected biological and toxin weapons use.

|103

|Ambassador Winfried Lang (Austria)

|BWC/CONF.II/13

|Third

|9. – 27. September 1991

|1. Expansion of the CBMs by including information on (i) national implementation measures such as legislation, (ii) past offensive and defensive biological weapons programs, and (iii) vaccine production facilities.

2. Establishment of an expert group on verification, VEREX, mandated to identify and examine potential verification measures from a scientific and technical standpoint.

3. Clarification that investigations under Article VI can also be requested through the Secretary-General and not only through the Security Council.

4. Reaffirmation that the BWC covers not just agents affecting humans but also those affecting animals and plants.

5. Clarification of the coordinating role of intergovernmental organizations responding to attacks allegedly involving biological weapons.

6. Assertion that information on the implementation of Article X on peaceful uses of the biological sciences should also be provided to the United Nations.

|116

|Ambassador Roberto Garcia Moritan (Argentina)

|BWC/CONF.III/23

|Fourth

|25. November – 6. December 1996

|1. Reaffirmation that the use of biological weapons is considered prohibited under Article I.

2. Assertion that the destruction and conversion of former biological weapons and associated facilities should be completed before accession to the BWC.

3. Recommendation of specific measures to improve the implementation of Article X on peaceful uses of the biological sciences.

|135

|Ambassador Sir Michael Weston (U.K.)

|BWC/CONF.IV/9

|Fifth

|19. November – 7. December 2001;

11. – 22. November 2002

|1. Suspension of the conference by one year in response to the U.S. proposal to terminate the Ad Hoc Group's mandate.

2. Establishment of an intersessional program, including annual Meetings of States Parties and Meetings of Experts, to promote discussion and agreement on a variety of topics relevant to the BWC.

|144

|Ambassador Tibor Toth (Hungary)

|BWC/CONF.V/17

|Sixth

|20. November – 8. December 2006

|1. Establishment of the BWC Implementation Support Unit within the United Nations Office for Disarmament Affairs in Geneva to provide administrative support and strengthen the Convention in other ways.

2. Renewal and modification of the intersessional program.

|155

|Ambassador Masood Khan (Pakistan)

|BWC/CONF.VI/6

|Seventh

|5. – 22. December 2011

|1. Revision of the CBM reporting forms, including the deletion of CBM form D on the active promotion of contacts.

2. Establishment of a database to facilitate assistance and cooperation under Article X.

3. Establishment of a sponsorship program to support developing States Parties to participate in the annual BWC meetings.

4. Reform of the convention's financing system.

|165

|Ambassador Paul van den IJssel (Netherlands)

|BWC/CONF.VII/7

|Eighth

|7. – 25. November 2016

|1. Renewal of the ISU's mandate, the sponsorship program, the intersessional program, and the Article X assistance and cooperation database.

|177

|Ambassador György Molnar (Hungary)

|BWC/CONF.VIII/4

|Ninth

|28. November – 16. December 2022

|1. Establishment of a Working Group to identify, examine and develop specific and effective measures, including possible legally-binding measures, and to make recommendations to strengthen and institutionalise the Convention in all its aspects.

2. Decision to develop with a view to establishing two mechanisms, one on international cooperation and assistance under article X, and the other on the review of scientific and technological developments relevant to the Convention.

3. Renewal of the ISU's mandate and the sponsorship program.

4. Progress of the implementation of decisions and recommendations agreed upon at the Eighth Review Conference.

|184

|Ambassador Leonardo Bencini (Italy)

|BWC/CONF.IX/9

|Tenth

|No later than 2027 The intersessional program includes both annual Meetings of States Parties (MSP)—aiming to discuss, and promote common understanding and effective action on the topics identified by the Review Conference—as well as Meetings of Experts (MX), which serve as preparation for the Meeting of States Parties. For example, a 2019 report by the Stockholm International Peace Research Institute finds that "advances in three specific emerging technologies—additive manufacturing (AM), artificial intelligence (AI) and robotics—could facilitate, each in their own way, the development or production of biological weapons and their delivery systems". On the other hand, these scientific developments may improve pandemic preparedness by strengthening prevention and response measures.

Technological challenges in the verification of biological weapons

There are several reasons why biological weapons are especially difficult to verify. First, in contrast to chemical and nuclear weapons, even small initial quantities of biological agents can be used to quickly produce militarily significant amounts. Second, biotechnological equipment and even dangerous pathogens and toxins cannot be prohibited altogether since they also have legitimate peaceful or defensive purposes, including the development of vaccines and medical therapies. BWC States Parties agreed at the Meeting of States Parties in 2018, which was cut short due to funding shortfalls, on a package of remedial financial measures including the establishment of a Working Capital Fund. This fund is financed by voluntary contributions and provides short-term financing in order to ensure the continuity of approved programs and activities.

References

External links

Official resources created by the United Nations Office for Disarmament Affairs
Official website of the Biological Weapons Convention
Full text of the Biological Weapons Convention, Treaty Database
Brochure: The Biological Weapons Convention: An Introduction
Meetings Place. A page with details on disarmament meetings, including documents and presentations.
BWC Meeting of States Parties
BWC Meetings of Experts
Electronic Confidence-Building Measures facility
Article X cooperation and assistance database
External resources
"Treaties and Regimes: The Biological Weapons Convention", Nuclear Threat Initiative
"The Biological Weapons Convention (BWC) at a Glance", Arms Control Association
"The Historical Context of the Origins of the Biological Weapons Convention (BWC)", University College London
"Understanding Biological Disarmament: Final Report"