Chemical welfare: Sudan chlorine bombs: Its law and impact

Persistent allegations regarding chemical weapons deployment in the Sudanese civil war have gained fresh momentum following newly revealed evidence.

Reports published by US media outlets The New York Times and The Washington Post in September 2026, based on intelligence materials provided by an anonymous Middle Eastern agency, outline efforts by the Sudanese Armed Forces to develop chlorine-based weapons. These munitions were reportedly aimed at the paramilitary Rapid Support Forces during the prolonged conflict in and around Khartoum—a campaign marked by heavy bombardment of civilian areas between April 2023 and March 2025, before the army secured full control of the capital in January 2026.

Chemical weapons specialist Anneleen van der Meer examines the technical mechanisms, battlefield tactics, and international legal frameworks surrounding these latest findings.

Weaponising dual-use chemicals

Chlorine is a widely used industrial chemical with legitimate civilian applications, notably in drinking water purification. However, when stored under pressure as a liquefied gas, it can be transferred into military munitions for battlefield deployment.

When chlorine munitions strike their targets, the outer casing ruptures, causing an abrupt drop in internal pressure that rapidly evaporates the liquid into toxic gas. Exposure to chlorine vapour causes severe physical harm:

Respiratory System Damage: Immediate irritation of airways and mucous membranes.
Pulmonary Oedema: Chemical burns that trigger fluid accumulation in the lungs, leading to asphyxiation.
Categorised as an asphyxiating agent alongside chloropicrine — a substance reportedly used by Russia in Ukraine — and phosgene, chlorine was among the earliest toxic agents deployed during the First World War (1914–1918). Because chlorine is accessible and inexpensive to weaponise, it remains a persistent threat. Delivery mechanisms include ground-released cylinders, artillery shells, aeroplanes, and drones, with air-dropped munitions identified as the preferred vector in Sudan.

This strategy mirrors tactics employed by the Bashar al-Assad regime during the Syrian civil war (2011–2024), where chlorine bombs were regularly dropped from helicopters and fixed-wing aircraft onto urban targets.

Although chlorine gas can prove lethal at high concentrations without immediate medical intervention, its tendency to dissipate quickly in elevated temperatures reduces its direct mortality rate. Nevertheless, military forces deploy chlorine in combination with conventional high explosives to gain distinct tactical advantages:

Triggering widespread panic among civilian populations and enemy troops.
Flushing defenders out of fortified cover into open areas vulnerable to conventional weapons.
Overwhelming local healthcare facilities and emergency response teams.
Applying psychologically devastating pressure while reducing chemical persistence to minimise detection.

International legal frameworks

Chemical weapons have been outlawed under international law for nearly a century, beginning with the 1925 Geneva Protocol. Universally recognised as inhumane due to their indiscriminate nature and the unnecessary suffering they inflict, chemical munitions were further banned under the Chemical Weapons Convention (CWC) of 1993. Entering into force in 1997, the treaty has 193 member states, including Sudan, which signed on in 1999.

Nations violating international bans face economic sanctions or diplomatic isolation. However, sanctions have historically shown limited deterrence; both Syria and Russia were subjected to multilateral sanctions over chemical weapon usage but continued military operations without compliance.

The CWC recommends that member states pursue all legal measures to stop violations, including diplomatic pressure, economic restrictions, or UN Security Council-approved military intervention if global security is threatened.

Individuals responsible for developing, stockpiling, or employing chemical weapons can face prosecution for war crimes and crimes against humanity. Although the International Criminal Court (ICC) prosecutes such offences, Sudan is not a state party, meaning any ICC prosecution requires a formal referral from the UN Security Council.

Consequently, domestic prosecution often serves as a more accessible route. Historical precedents include Iraq’s prosecution of Ali Hassan al-Majid ("Chemical Ali") under Saddam Hussein, and Syria's recent actions concerning former president al-Assad.

Impact and next steps for Sudan

Sudan has faced chemical warfare allegations in the past. In 2016, Amnesty International reported blistering agent attacks in Darfur, though no independent international investigation took place.

However, allegations covering the 2023–2025 period drew swift international scrutiny, culminating in US government sanctions in 2025. Intelligence shared with The New York Times indicates these measures prompted Sudanese army leader Abdel al-Burhan to instruct chemical weapons leaders to "remove all traces" of the programme.

Whether individual commanders are held accountable depends on how effectively Sudanese domestic law incorporates international treaties. Ultimately, state parties to the CWC should demand an official inspection by the Organisation for the Prohibition of Chemical Weapons (OPCW) to verify compliance and reinforce global norms.