Legal Perspectives on the Use of Chemical Weapons in Syria and Iraq

Publication Date: 
Tuesday, October 4, 2016

On the 21st of September, CNN reported that ISIS was suspected of firing a shell containing mustard gas at an airbase in Iraq used by United States and Iraqi troops. This is by no means the first reported use of chemical weapons in recent months and years. In fact just one month earlier, on the 25th of August, a United Nations Security Council mandated investigation team (OPCW Joint Investigative Mechanism (JIM)) concluded that both the Assad regime and ISIS had undertaken chemical attacks in Syria in 2014 and 2015. This is the first time that the UN had made an authoritative assertion of attribution and responsibility in relation to the use of chemical weapons in the Syrian conflict. These findings came barely a few weeks after it was widely reported that chlorine gas had been used in Aleppo and Saraqeb.

The alleged use of chemical weapons in Syria can be traced back to 2013, where the first reports came through concerning the use of sarin gas in a multitude of locations, including Khan Al Asal; Sarqib; Ghouta and Jobar. Both the Syria Commission of Inquiry and treaty based Organisation for the Prohibition on Chemical Weapons (OPCW) investigated such attacks, with the Syria Commission concluding that “Chemical weapons, specifically sarin, were found to have been used in multiple incidents during the conflict.” The report of the 25th of August 2016 is significant in specifically identifying those responsible, as aspect absent from these previous reports.

As the use and presence of chemical weapons appears to be spreading from Syria to Iraq, this troubling dynamic to the conflict landscape has serious implications not only legally but also from a humanitarian perspective.

The use of chemical weapons has long triggered an elevated level of revulsion and abhorrence, not only in terms of legal regulation, but also in the mind of the wider public. Effects of sarin, such as sensations of suffocation, respiratory struggles, paralysis, and retching often occurring without the victims’ awareness of what they are being subjected to, all combine to reinforce the egregious nature of these weapons.

Thankfully, until the more recent uses in Syria and potentially Iraq, the use of such weapons in the modern conflict context has been relatively rare, with notable exceptions being during the Iraq-Iran conflict in 1988; and again in 1988 with the use by Iraqi forces in Halabja against Iraqi Kurds. In terms of historical context the first modern use of large-scale chemical warfare can be dated back to 1915 when the German army released 150 tons of chlorine gas against Allied soldiers.

Legal Framework

Unlike other aspects of conflict regulation, which have been subject to more modern regulation, the specific and strict prohibitions on the use of chemical weapons date back to the late 19th Century and were further crystalized in direct terms in The 1925 Geneva Protocol. Importantly the prohibitions are strict and unambiguous. Chemical weapons are prohibited as a means of warfare.  Therefore unlike other protection gaps highlighted in the Second World War, chemical weapons regulation was already robust and comprehensive in terms of setting out the prohibition on use.  Throughout the 1960s and 1970s the United Nations General Assembly adopted several resolutions consistently reiterating the need for strict respect for the 1925 Geneva Protocol and condemning in clear terms all and any actions that ran contrary to them.

It is also important to not forget that the specific nature of chemical weapons goes against some of the most basic notions of humanitarian law set out in the Geneva Conventions and its protocols, such as the requirement for distinction in attacks, the prohibition on indiscriminate attacks, and the prohibition on causing unnecessary suffering and superfluous injury. In case of any possible lingering doubt, the ICRC Customary International Law Study of 2005 confirmed that the strict prohibition on the use of chemical weapons applies both in non-international armed conflict and international armed conflict.

Whilst restating the historical nature of the prohibition on the use of chemical weapons the legal regulation of chemical weapons was further indeed strengthened in disarmament terms in the early 1990s. The main developments under the 1993 Chemical Weapons Convention (CWC) was to move beyond prohibition of use but take steps to reduce the risk of use, addressing: the prohibition on the development; production; stockpiling or; acquisition or retention of biological agents which have no peaceful purpose. These prohibitions also extend to equipment or means of delivery designed to use such agents. Importantly, these treaties demand that states actively destroy existing stockpiles.

Challenges in the dual purpose of these products

Despite the clear terms of the legal prohibition on the use, development, production and stockpiling, etc., there are important activities in relation to chemical components that fall outside of the disarmament and stockpile destruction obligations of the CWC. Such as is the nature of utility of the chemical components as such, the idea that risk of misuse of these chemicals can be fully eradicated is impossible.  For example, precursors for nerve agents are also necessary materials for the production of a range of products, including pesticides, flame-retardants. In addition, sulfur mustard is used as a cancer treatment. Pragmatism demands that products with dual use functions escape and sidestep the comprehensive disarmament requirements, but at the same time it must be accepted that they pose a degree of risk in terms of weaponization and/or proliferation.

International Criminal Law

While it does not mention chemical or biological weapons by name, the Rome Statute of the International Criminal Court does list as war crimes in international armed conflict “employing poison or poisoned weapons and employing asphyxiating, poisonous or other gases, and all analogous liquids, materials or devices”. The use of chemical and biological weapons in general can be considered to fall within this provision, although not all international lawyers hold the same view. Whichever view is taken, the failure to specifically use the terms chemical and biological weapons does lead to a degree of unwelcome ambiguity.

A further weakness of the Rome Statute’s approach to criminalizing the use of chemical and biological weapons it its the failure to apply the prohibitions to non-international armed conflict. The Review Conference of the Rome Statute in 2010 thankfully corrected this unjustifiable absence and unnecessary loophole. However, such an amendment only binds those states that ratify it; to date only 30 states have done so.

In short, it can be concluded that whilst the IHL framework is clear and fairly robust, is it more difficult to make the same clear case for the international criminal framework.


As evidenced by recent incidents in Syria, there is grave concern that foundational concepts of modern IHL are being directly and continually violated by both states and armed non-state actors. Moving forward, this raises huge concerns that the erosion of will further undercut its utility to operate as an effective and relevant tool of humanitarian protection in modern conflict.

Aside from the destruction of weapons caches the challenge remains in probing and continually questioning states’ claims that supplies of chemical agents are truly intended for the permitted peaceful purposes. In addition, states themselves need to take all steps to reduce the risk of proliferation, including assessing risks associated with the outbreak of conflict in their country or region.

Finally in regard to accountability, the recent use of chemical weapons demands a response from the international community. The global community must come to together and take the necessary steps to ensure that those committing such egregious acts are held to account. At the forefront of this should be the referral by the UN Security Council of the situation in Syria to the ICC. Otherwise, there is a significant risk that such behavior will repeat itself not only in Syria, but in other conflicts as well, such as what may have occurred in Iraq on the 21st of September 2016.

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