SEDE II

Committee on Security and Defence II

Introduction

All along the Western Front of World War I, soldiers in trenches began to breathe abnormally and choke, from what was later revealed to be symptoms caused by the dispersion of chlorine and phosgene, toxic gases that attacked the respiratory system, causing suffocation and death, as well as mustard gas, a blister agent, inflicting deep and excruciating burns, often leading to long-term suffering.¹ Among weapons of mass destruction (WMDs), chemical warfare (CW) is comparable to biological and nuclear weapons, and can be considered one of humankind’s most brutal inventions. Chemical weapons are relatively easy to produce, inexpensive, indiscriminate, and capable of causing mass human casualties even when used in small quantities.²

Ever since these devastating events, there has been significant progress thanks to multilateralism and the active advancement of human rights, culminating in the adoption of the The Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction (“Chemical Convention” or “CWC”), which entered into force on April 29, 1997. As of January 2025, 193 states are state parties to the Convention, placing 98%³ of the global population under the protection of the Convention. The Convention represents a key milestone, safeguarding the world from the horrors of the past and establishing an international regime for the non-proliferation of chemical weapons.

However, the growing threat of CW use by state actors, such as the Syrian government’s 2013 attack on civilians in Ghouta,⁴ and by non-state actors, including Da’esh (also known as the Islamic State, ISIL, or ISIS),⁵ as well as the alleged use of CW by Russian forces during the Russian aggression on Ukraine,⁶ sets a troubling precedent. Lastly, the advancement of new technologies, while highly beneficial for scientific progress and overall human development, has also raised concerns about their potential misuse.

Fundamental Challenges

The development of new technologies, such as modern analytical tools that enable real-time detection of even trace amounts of chemical warfare agents,⁷ has significantly improved the ability to detect, safely handle, and destroy toxic chemicals. However, new technologies also raise legitimate concerns about their potential misuse in chemical weapon production, by both state and non-state actors. While these technologies contribute to fields such as medicine development, they also make it easier and faster to research and produce chemical weapons, requiring less time and expertise. For example, the rise of 3D printing could enable faster production of specialized equipment needed for chemical weapon deployment, completely bypassing traditional supply chains and making detection more difficult. The scientific community has closely monitored the development of synthetic biology, which could potentially advance the creation of chemical and biological agents from easily accessible materials. While developing effective chemical agents remains complex,⁸ advancements in synthetic biology could further lower barriers and challenge current verification systems. These mechanisms primarily rely on on-site inspections and data analysis:⁹ 

1. The Verification Division collects, reviews, and cross-checks mandatory declarations from Organisation for the Prohibition of Chemical Weapons (OPCW) member states regarding their chemical facilities, weapons stockpiles, and dual-use chemicals.
2. The Inspectorate Division carries out on-site inspections at chemical plants, weapons storage sites, and destruction facilities.
3. The OPCW Laboratory provides scientific and technical support on verification-related analytical issues. It maintains advanced methods and technologies for sampling and analysis, supports routine and non-routine inspections, and assists in training and certifying inspectors. The Laboratory also manages the OPCW Central Analytical Database (OCAD) and ensures that OPCW Designated Laboratories meet high proficiency standards for impartial chemical analysis in investigations of alleged chemical weapons use.

While these systems are currently effective, threats of new technologies can significantly challenge them. For example, generative AI has the potential to create new ways of dispersing toxic chemicals, make them more long-lasting, and better able to penetrate protective equipment, as well as creating weapons that can bypass medical responses or export controls, by using alternative precursor chemicals and new synthetic compounds.¹⁰ Equally concerning are cyber threats,¹¹ which pose a risk to the security and accuracy of OPCW databases.

With modern technologies potentially accelerating the accessibility of chemical weapon production, a major concern is who might attempt to create and use them. A UN investigative team examining crimes committed by the terrorist organization Da’esh reported that, during its rule over its self-proclaimed caliphate, the group developed “at least eight chemical agents, tested them on humans, and carried out at least 13 attacks,”¹² raising serious concerns in the international community. 

The fact that the use of chemical weapons by non-state actors has rarely, if ever, been prosecuted in national or international courts presents a significant challenge for lawmakers seeking to adapt existing legal frameworks to hold such actors accountable. One major obstacle is that the CWC, under Article I, only binds state actors, whereas individual accountability for non-state actors requires a referral to the UN Security Council (UNSC), which then must refer the case to the International Criminal Court (ICC) under Article 13(b) of the Rome Statute. If a case successfully reaches the ICC, the court can prosecute individuals under its existing war crimes and crimes against humanity provisions, as the Rome Statute does not explicitly classify chemical weapons use as a separate crime.¹³ While the process is complex, history shows that prosecution is possible. Precedents from international tribunals, such as the ICTY’s ruling on chain-of-command responsibility in Prosecutor v. Tadić (1999), highlight a growing shift in international legal norms toward holding individuals accountable.

Lastly, Europe fortunately has not witnessed the large-scale use of chemical weapons since World War I. However, this has led to a decreased awareness among European citizens of the immense dangers these weapons pose. The use of the deadly Soviet-era nerve agent¹⁴ Novichok, which is prohibited under the CWC, in the case of the poisoning of Sergei and Yulia Skripal¹⁵, and in the poisoning of Russian opposition leader Alexei Navalny,¹⁶ along with allegations of Russia’s use of chemical weapons in Ukrainian trenches,¹⁷ if proven true, would present significant challenges for international accountability and enforcement. Russia’s influential position as a permanent member of the UNSC grants it the power to veto any action that seeks to hold it accountable under international law, and the CWC in particular.

Key Stakeholders

The United Nations (UN General Assembly and UN Security Council)

Except for the Geneva Protocol of 1925, which predates the UN, most international legislation on chemical weapons non-proliferation has been developed under the UN framework. The CWC, was negotiated under the UN Conference on Disarmament and adopted by states. The OPCW, the treaty body responsible for implementing the CWC, relies on the UNSC for enforcement measures, particularly when a state is found in  violation of the treaty. The UNSC, under Chapter VII of the UN Charter (Articles 39-42), has the authority to impose sanctions or authorise military action if a state’s use of chemical weapons is deemed a threat to international peace and security. However, the veto power of permanent UNSC members (Article 27(3) of the UN Charter) could obstruct further enforcement measures. While only UNSC resolutions are binding, and UNGA are not (Article 25), the UN system holds significant diplomatic influence, using political pressure to encourage compliance.

Organisation for the Prohibition of Chemical Weapons

A body established under Article VIII of the CWC, specifically its Executive Council, composed of 41 rotating member states, is responsible for promoting the effective implementation of and compliance with the Convention. The OPCW can conduct fact-finding missions (FFMs) under Article IX of the Convention, to determine whether chemical weapons were used. In cases of non-compliance with the CWC, according to Article VIII(36), the Executive Council has the authority, in situations of particular gravity and urgency, to bring the matter directly to the attention of the United Nations General Assembly and the UNSC.¹⁸ However, while the OPCW can confirm violations, it does not have the authority to attribute responsibility unless granted a specific mandate by the UNSC,^{19 20} or compel states to comply with international obligations. Regardless, a violation of the CWC does damage to the international standing of the guilty state.²¹

The EU (European Commission, Council of the EU, and EEAS)

European Commission

The European Commission enforces the European Union’s policies on chemical weapons non-proliferation through several key actions by regulating the export, transit, brokering, and technical assistance of dual-use items, to prevent their misuse in developing WMDs. From 2014 to 2020, the Instrument contributing to Stability and Peace (IcSP) was the EU’s primary financial tool supporting security initiatives, including chemical weapons non-proliferation efforts. However, under new funding rules, the IcSP was merged into a new funding instrument.²² While the new arrangement includes security-related funding, its focus has shifted more towards broader conflict prevention and crisis response, reducing dedicated support for chemical non-proliferation due to budgetary and strategic prioritisation shifts.

Council of the European Union

The Council of the EU enforces the CWC by imposing restrictive measures (sanctions) to prevent the proliferation and use of chemical weapons.²³ These sanctions are proposed either by the High Representative of the Union for Foreign Affairs and Security Policy, a Member State, or in accordance with a UN resolution. Once adopted, Member States are responsible for enforcement, while the EU monitors and reviews the sanctions to ensure their relevance. As of February 2025, 25 individuals and 3 entities, mostly linked to the Syrian and Russian use of chemical weapons, are subject to EU sanctions, including asset freezes, financial restrictions, and travel bans. These sanctions were first adopted in 2018 under the EU’s Chemical Weapons Sanctions Regime and are periodically reviewed and adjusted. Beyond state actors, the EU has also sanctioned non-state entities, including Da’esh and other groups involved in the development or use of chemical weapons.

European External Action Service (EEAS)

Since most recent uses of chemical weapons have occurred outside EU Member States, the EEAS, as the EU’s key diplomatic body, manages the Union’s foreign policy toward these states and coordinates the EU’s overall approach, working closely with the OPCW²⁴ to address chemical weapons-related issues.

Civil Society 

NGOs such as Human Rights Watch and Amnesty International play an important role in raising public awareness about the devastating effects of chemical weapons and exerting international pressure on perpetrators by publishing research and advocating for action from the global community. Additionally, influential institutes and think tanks, such as the Stockholm International Peace Research Institute (SIPRI) and Chatham House, employ experts who analyze and propose policy solutions to address chemical weapons-related challenges. 

A notable civil society actor is also the CWC Coalition, an independent, international network dedicated to supporting the goals and universalization of the Chemical Weapons Convention (CWC). The White Helmets (Syria Civil Defence), a volunteer organization founded during the conflict in the Syrian Arab Republic, has played a crucial role in protecting and assisting civilians, particularly through search-and-rescue operations and emergency response.

Measures in place

International legal framework

The 1925 Geneva Protocol and the Chemical Weapons Convention are legacy international agreements aimed at eliminating chemical weapons. While the Geneva Protocol pioneered the ban of their use in war, it did not address production or stockpiling. The CWC later closed these legal gaps by requiring countries to destroy their chemical weapons and allowing inspections to ensure compliance. In response to the growing threat of non-state actors, the UNSC adopted Resolution 1540 in 2004. Unlike traditional treaties, the Resolution obligates all UN member states to prevent terrorist groups from acquiring WMDs by enforcing stricter national laws, border controls, and security measures. However, the Resolution faces challenges, including a lack of enforcement mechanisms and verification systems, making compliance completely voluntary. Many countries struggle to meet its requirements due to limited financial resources, and some view it as infringing on their sovereignty.²⁵ Despite these shortcomings, the resolution remains a crucial first step in addressing legislative gaps left by other treaties.

EU-based legal mechanisms

In reaction to the 2018 Syrian alleged use of chemical weapons²⁶ and the US, UK and France joint air attacks on “targets associated with the chemical weapons capabilities in Syria,”²⁷ the EU established a thematic sanctions regime to counter the threat posed by the proliferation and use of chemical weapons. This framework was formalized through Council Regulation (EU) 2018/1542 and Council Decision (CFSP) 2018/1544, both adopted on October 15, 2018. These measures allow the EU to impose restrictive actions, such as asset freezes and travel bans, on individuals and entities involved in the development, production, acquisition, stockpiling, and use of chemical weapons. Outside of the EU, both the UK and the US have their own sanctions regimes.²⁸

Historical context

Who has historically used chemical weapons and are different uses morally equivalent?

Ancient Athenians, French colonists in Algeria, both German and Allied forces in World War I,  Italy under Mussolini, Saddam Hussein²⁹ – showcasing the political diversity of the actors willing to resort to these methods. A binary view of geopolitical alliances cannot serve as the foundation for implementing international law.

A historical case of legal ambiguity is the U.S. Air Force’s use of Agent Orange and other defoliants during the Vietnam War (1961-1971), which had severe humanitarian and environmental consequences. Existing international treaties at the time, such as the 1925 Geneva Protocol, did not explicitly address herbicides used for defoliation purposes, as the primary intent³⁰ behind the U.S. campaigns was to remove dense foliage that provided cover for enemy forces and to destroy crops that could supply them, rather than to directly harm human populations. However, the extensive use of Agent Orange, which contained the highly toxic compound dioxin³¹, led to significant health issues among exposed populations, including US veterans, and caused long-term environmental damage. In response to the widespread environmental and health impacts observed, the United States ceased the use of Agent Orange in 1971, leading to the creation of a rule of customary law mostly prohibiting the use of herbicides, supported by state practice.³² Other subsequent international efforts sought to address the use of environmental modification techniques in warfare, leading to the adoption of the Environmental Modification Convention (ENMOD) in 1977. Regardless of later efforts to regulate the use of herbicides in warfare, this case illustrates the challenges posed by the absence of explicit legal definitions in international law. It highlights the need for more comprehensive legal frameworks that apply consistently, irrespective of the state or actor involved.

Who dies from chemical weapons, and what are the deeper societal consequences of their use?

Soldiers, civilians, mothers, children, and the generations to come. Chemical weapons are “weapons of terror.” Acutely, they cause severe respiratory distress, painful blisters and burns, choking, and organ failure. However, their impact goes far beyond the initial use. Over time, they leave communities with a persistent sense of fear and anxiety, “exacerbating pre-existing psychiatric disorders and further heightening the risk of mass sociogenic illness.”^{33 34} Chemical weapons also indiscriminately poison the environment, contaminating soil, air, and water. Their devastation does not end with those who die or suffer immediate injuries; generations after must endure the physical and psychological fallout of chemical weapons.

Outlook

Despite the horrific impact of chemical weapons throughout history, today’s international framework for chemical weapons non-proliferation is among the strongest arms control regimes, backed by global diplomatic efforts. However, for a world shifting away from multilateralism, and faced with a technological revolution, new challenges arise. From a legal standpoint, there is a dire need to hold non-state actors accountable in both international and non-international armed conflicts. On the other hand,  the rapid advancement of technology calls for improving verification and detection mechanisms. This means integrating AI and other tools to track and prevent the misuse of chemical weapons before they become a threat. Lastly, it is crucial to plan damage control strategies in case a state actor, such as Russia, resorts to use of WMDs again, alongside a continuing diplomatic effort for Egypt, Israel, North Korea, and South Sudan to join the CWC.

Food for thought

• How can we ensure that technological advancements support human-centered, community-driven development rather than being misused to cause harm?
• How can enforcement mechanisms be strengthened to uphold the Chemical Weapons Convention, especially against non-signatory states and non-state actors operating outside traditional legal systems?
• As global politics shift from multilateralism to Realpolitik, how can we prevent double standards in the application of international law?

Further reading

ARTICLE IN THE Blog of the European Journal of International Law

Twelve Years On: An Exceptional Chemical Weapons Tribunal

Read more

footnotes

1.  United Nations Office for Disarmament Affairs (n.d.). Chemical weapons. Link ↩︎
2.  Ganesan, K., Raza, S. K., & Vijayaraghavan, R. (2010). Chemical warfare agents. Link ↩︎
3.  OPCW (2025). OPCW by the numbers. Link ↩︎
4.  ​​United Nations (2013). Report of the United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic. Link ↩︎
5.  OPCW (2024). OPCW identifies ISIL perpetrators of 2015 chemical attack in Marea, Syria. Link ↩︎
6.  US Department of State (2024). Imposing New Measures on Russia for its Full-Scale War and Use of Chemical Weapons Against Ukraine. Link ↩︎
7.  United Nations Interregional Crime and Justice Research Institute (2024). UNSCR 1540: Emerging technologies and their implications for chemical disarmament and non-proliferation. Link ↩︎
8.  Jefferson, C., Lentzos, F., & Marris, C. (2014). Synthetic biology and biosecurity: Challenging the “myths.” Link ↩︎
9.  OPCW. (n.d.) The Verification Regime of the Chemical Weapons Convention: An Overview. Link ↩︎
10.  Marc-Michael Blum (2025). Artificial Intelligence and Chemical Weapons. Link  ↩︎
11.  Arms Control Association (2018). Russia Charged With OPCW Hacking Attempt. Link ↩︎
12.  United Nations (2023). UN investigative team outlines findings around ISIL chemical weapons use. Link ↩︎
13.  Instead, prosecution needs to rely on customary international law and Article 8(2)(b)(xvii) and (xviii) of the Rome Statute, which prohibit the use of poison or poisonous weapons and gases in international armed conflicts, leaving out a legal gap for non-international armed conflicts. ↩︎
14.  Nerve agents are a highly toxic chemical weapon that inhibit Acetylcholinesterase (AChE), causing excessive nerve stimulation. AChE is rapidly absorbed through the skin and lungs, leading to symptoms such as muscle spasms, respiratory failure, and paralysis. Nerve agents are classified into G-series (e.g., Sarin, Soman) and V-series (e.g., VX), with V-agents being more persistent and potent (OPCW, n.d.). ↩︎
15. OPCW (n.d.). Incident in Salisbury. Link ↩︎
16.  OPCW  (n.d.). The case of Mr. Alexei Navalny. Link ↩︎
17.  US Department of State (2024). Imposing New Measures on Russia for its Full-Scale War and Use of Chemical Weapons Against Ukraine. Link ↩︎
18.  The UNSC can take additional steps to enforce accountability under Chapter VII of the UN Charter, such as referring cases to legal bodies like the ICC or imposing measures under Article 41, including economic sanctions, travel bans, and arms embargoes. In extreme cases, the UNSC can also authorize military interventions. ↩︎
19.  Such an example was the OPCW-UN Joint Investigative Mechanism (JIM), established by UN Security Council Resolution 2235, which had the mandate to identify perpetrators in the Syrian Arab Republic, but this mechanism was dissolved in 2017 after Russia vetoed its renewal.
    United Nations. (2017). Security Council fails to renew mandate of Joint Investigative Mechanism on chemical weapons use in Syria, as permanent member casts veto. Link ↩︎
20.  In 2018, the OPCW was granted the authority to attribute responsibility in cases where chemical weapons use was confirmed in Syria. The decision Addressing the Threat from Chemical Weapons Use (C-SS-4/DEC.3) led to the formation of the Investigation and Identification Team (IIT), tasked with identifying perpetrators in cases not covered by the JIM. ↩︎
21.  BBC. (2024). French court confirms Bashar al-Assad arrest warrant over Syria chemical attack. Link ↩︎
22.  European Commission. (2021). European Commission welcomes the endorsement of the new €79.5 billion NDICI-Global Europe instrument to support EU’s external action. Link ↩︎
23.  Council of the European Union. (2024). Council Decision (CFSP) 2018/1544 of 15 October 2018 concerning restrictive measures against the proliferation and use of chemical weapons (consolidated version: 17 July 2024). Link ↩︎
24.  European External Action Service. (2023). EU and OPCW: Second high-level chemical weapons’ dialogue in Brussels. Link ↩︎
25.  Arms Control Association. (2012). Nearly to the brink: The tasks and capacity of the 1540 Committee. Link ↩︎
26.  United Nations. (2023). ‘Reasonable grounds to believe’ Syrian government used chlorine gas on Douma residents in 2018, head of chemical weapons monitoring organization tells Security Council. Link ↩︎
27.  Al Jazeera. (2018). US and allies strike Syria: The full story. Link ↩︎
28.  Global Sanctions. (n.d.). Chemical Weapons & Non-Proliferation. Link ↩︎
29.  Science History Institute. (2015). A brief history of chemical war. Link ↩︎
30.  The Diplomat. (2022). Agent Orange in Vietnam: Legality and US Insensitivity. Link ↩︎
31.  Institute of Medicine Committee. (1994). Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Link ↩︎
32.  IHL Databases. (n.d.). Customary international law – Herbicides. Link ↩︎
33.  Wessely, S., Hyams, K. C., & Bartholomew, R. (2003). Psychological implications of chemical and biological weapons. Link ↩︎
34.  Mass sociogenic illness happens when a group of people start experiencing similar physical symptoms, like headaches or dizziness, even though there is no physical cause, such as a virus or bacteria. These symptoms happen naturally because of the mind’s reaction to fear or tension. ↩︎