The Ferguson Social Unrest and the Use of Tear Gas: Some Thoughts from the European point of view

I’m very pleased to host another guest post from Dr. Daniel Rietiker.  This time Daniel provides a very interesting comparative insight into how the European Court of Human rights has approached the issue of the use of tear gas for riot control purposes.  I thought this analysis was particularly useful and interesting being at the juncture of arms control law and international human rights law.  I think this is an area that could be more thoroughly explored in scholarly literature.


The Ferguson Social Unrest and the Use of Tear Gas: Some Thoughts from the European point of view

Daniel Rietiker, PhD


On August 9, 2014, Michael Brown, an unarmed African-American, was fatally shot by a white police officer in Ferguson, Missouri. The incident was followed by heavy protests and civil unrest that lasted for weeks. The local police responded by using non-lethal weapons and tear gas. These tragic events raise various questions of international law. Probably the most relevant question for arms control lawyers is whether the use of tear gas by the police in the aftermath of the shooting in response to the protests was adequate and legitimate. The European Court of Human Rights (hereafter : ECtHR) has a well-established practice in the field of riot control, including the use of tear gas, that will be briefly explained here. A more comprehensive study on the interplay between arms control and human rights will be presented by this author in a forthcoming publication.

[the following observations, as far as they concern case law, are based on the ECtHR’s legal summaries that can be found on the Court’s website:

The lawfulness of riot control measures, in particular the use of tear gas, in the light of the jurisprudence of the ECtHR

It can be recalled that under the Chemical Weapons Conventions (hereafter: CWC), “law enforcement including domestic riot control purposes” are considered “purposes not prohibited” under the convention (Article II.9.d CWC). Moreover, Article I § 5 CWC stipulates that States Parties undertake not to use riot control agents as a method of warfare. The practice of the ECtHR in numerous cases in particular against Turkey in respect of the use of tear gas to counter potentially violent demonstrations reflects this logic. The Court examines these cases, inter alia, in the light of Article 3 of the European Convention on Human Rights (hereafter: “ECHR”), that reads as follows:

Article 3: Prohibition of torture:
No one shall be subjected to torture or to inhuman and degrading treatment or punishment.

Article 3 ECHR constitutes one of the cornerstones of the human rights protection and democratic society in Europe. It flows from its unqualified terms that this provision contains an absolute guarantee. Moreover, it cannot be derogated from in time of war or other public emergency (Article 15 § 2 ECHR). In other words, the States do not enjoy any margin of appreciation under Article 3, but have to refrain from inflicting the prohibited treatment in all circumstances, even for the highest reason of public interest.

The ECtHR interprets and applies exclusively the ECHR. It is not the guardian of other international treaties, such as the CWC. On the other hand, the Court does not interpret the ECHR in isolation, but in harmony with other applicable “relevant rules of international law”, as required by Article 31 § 3 c) of the 1969 Vienna Convention on the Law of Treaties (CVDT). Therefore, it is not surprising that the Court, in the examination of a possible violation of Article 3 by the use of tear gas, refers to the CWC, expressing its point of view in the following terms (Oya Ataman v. Turkey, no. 74552/01, Judgment of 5 December 2006):

17. Under Article I § 5 of the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction of 13 January 1993 (“the CWC”), each State Party undertakes not to use riot control agents as a method of warfare. Tear gas or so-called “pepper spray” are not considered chemical weapons (the CWC contains an annex listing the names of prohibited chemical products). The use of such methods is authorized for the purpose of law enforcement, including domestic riot control (Article II § 9 (d)). Nor does the CWC state which State bodies may be involved in maintaining public order. This remains a matter for the sovereign power of the State concerned. The CWC entered into force with regard to Turkey on 11 June 1997.
18. It is recognized that the use of “pepper spray” can produce effects such as respiratory problems, nausea, vomiting, irritation of the respiratory tract, irritation of the tear ducts and eyes, spasms, chest pain, dermatitis or allergies. In strong doses, it may cause necrosis of tissue in the respiratory or digestive tract, pulmonary oedema or internal haemorrhaging (haemorrhaging of the suprarenal gland).

It derives from these paragraphs that, in situations of riots, protests and social unrest, the appropriate use of tear gas can be a justified and proportionate use of force and therefore turn out to be compatible with Article 3 ECHR. Nevertheless, the Court has found violations of this provision as a result of an unclear legal provisions authorizing tear gas or in cases where the law-enforcement authorities had made improper or unnecessary use of tear gas (substantive limb of Article 3) [see, for instance, the case Abdullah Yaşa and Others v. Turkey, no. 44827/08, 16 July 2013, where the applicant had been injured in the nose by a tear gas canister fired by a police officer; his injuries had unquestionably been serious enough to meet the threshold of Article 3 ECHR].

Moreover, even though the threshold of Article 3 is generally not met by the appropriate use of tear gas, the authorities are still under a procedural obligation to conduct an in-depth investigation into alleged violations of human rights (formal limb of Article 3 ECHR). Under this duty, the State has to conduct a satisfactory investigation allowing the accurate establishment of facts, as well as the identification and prosecution of the officers responsible for acts amounting to ill-treatment in the sense of Article 3 ECHR.

It is also noteworthy that in some instances, the Court referred to another human rights body, namely the European Committee for the Prevention of Torture and Inhuman and Degrading Treatment or Punishment (CPT), that had repeatedly expressed concerns over the use of tear gas in law-enforcement situations and urged the States to adopt clearer directives in national law on that subject. This was also the case in the recent judgment İzci v. Turkey (42606/05, 23 July 2013), where the Court, unanimously, found violations of the substantive and procedural aspects of Article 3 of the ECHR by the use of disproportionate force and lack of an effective investigation, and besides a violation of Article 11 on account of the failure to respect the applicant’s right to freedom of assembly. In this case, the applicant had taken part in a demonstration in Istanbul to celebrate Women’s Day which had ended in clashes between police and protesters. Video footage of the events showed police officers hitting a large number of demonstrators with truncheons and spraying them with tear gas. Women who had taken refuge in shops were dragged out by the police and beaten up. The police officers had not issued any warnings to disperse demonstrators before attacking them and the demonstrators, for their part, had not tried to respond to the attack but had only tried to flee.

This case is a typical example for the repeated violations of the ECHR that occur in demonstrations in Turkey. What is remarkable about this case is the fact that Court considered these problems as “systematic”, reiterating that it had already found in over 40 judgments against Turkey that the heavy-handed intervention of law-enforcement officials in demonstrations had amounted to a violation of Article 3 and/or Article 11 ECHR. The common feature of these cases is the unwillingness of the police forces to show a certain degree of tolerance towards peaceful gatherings and, in some instances, the precipitate use of force, including tear gas. Moreover, in over 20 of the judgments, the Court had already observed the failure of the Turkish authorities to carry out effective investigations into allegations of ill-treatment by law-enforcement personnel during demonstrations. It further stressed that 130 applications against Turkey concerning the right to freedom of assembly and/or use of force by law-enforcement officials during demonstrations were currently pending.

Considering the perspective that generally prompts the procedure with a view of implementing the final judgments, combined with the Court’s clear message in the İzci case, there is hope that the Committee of Ministers of the Council of Europe (CoE) – the body responsible for the supervision of the implementation of the ECtHR’s judgments (Article 46 ECHR) – will impose on Turkey strong measures, such as an order to review national legislation and to train the members of the police in order to comply with Article 3 in law-enforcement situations including the use of tear gas.


It goes without saying that the cases mentioned above are not identical to the circumstances of the unrest in Ferguson following the shooting of Michael Brown, nor is the legal framework for the use of force by the police the same. In the European context, a very high standard applies, both on the substantive and the formal (procedural) level. As far as the latter is concerned, and taking the Ferguson events as example, the investigating authority would have to establish what really happened in the aftermath of August 9, 2014, and it would ultimately incumbent on the judges to decide whether the force used by the police to counter the riots, including the use of tear gas, was in line with the applicable law and the state of art in this field. Such a thorough international scrutiny, based on a well-established practice by the ECtHR, does not exist in the United States.

(Daniel Rietiker, PhD, Lecturer in international law, University of Lausanne, Swiss Member of the ILA’s International Committee on Nuclear Weapons, Non-Proliferation & Contemporary International Law and Visiting Fellow at the Human Rights Program of Harvard Law School, spring/summer terms 2014).


4 Comments on “The Ferguson Social Unrest and the Use of Tear Gas: Some Thoughts from the European point of view”

  1. S. Batsanov says:

    Daniel Rietiker offered an interesting angle of looking at the issue of tear gas for riot control purposes. My thanks to him and to Dan Joyner for “hosting” his comments on ACL. I have no reason to whatsoever to question any of his observations and conclusions, but but would like to add a couple of brief comments.
    1. I believe it would be very useful, indeed for various countries to study and exchange views on best practices in the field of the use of riot control agents for legitimate purposes. It follows from Rietiker’s post that while the the use could be acceptable in the context of the CWC, different legal and operational regimes around the world may offer different solutions to what is acceptable (or not) from the humanitarian perspective. In my view, the more stringent the criteria, the better – also because indirectly, at least, it would help strengthen relevant norms of the CWC and promote the culture of compliance with them. Riot control agents and law enforcement are one of the most ambiguous ares of the CWC, which in many other respects is one of the most stringent international treaties. So, perhaps, this process of mutual information and sharing could also contribute to confidence building in this specific area of CWC implementation. Naturally, it has to be undertaken outside the formal process of CWC implementation and compliance.
    2. It was also interesting to note that some of the interpretations (or, should I say, views) of the CWC provisions, given by the ECtHR, are not correct. ECtHR is making a rather common mistake when it says that “the CWC contains an annex listing the names of prohibited chemical products” and that since tear gas and pepper spray are not in that annex, they are not considered chemical weapons. In fact, the inclusion or non-inclusion of chemicals into one of the schedules in the annex to the CWC does not mean that they are prohibited. There are no chemical products that are prohibited completely under CWC. Schedules mean different degrees of limitations (such as allowed quantities or possibility to sell to non-parties) and of verification (including thresholds of declarations). According to the CWC, riot control agents can only be chemicals, not included on the schedules; in other words, if you have a chemical, seemingly having properties of a riot control agent (chloropicrin), but it is on a schedule, it is prohibited to use it for riot control and law enforcement. Furthermore, in accordance with para 1a) of Article II of the CWC, if the types and quantities of chemicals used for non-prohibited purposes (such as riot control and domestic law enforcement, which we are discussing here), are not consistent with such purposes, a case can be made for characterizing these chemicals as chemical weapons. This is a bit theoretical, but one day it may become a practical issue. That is why different norms and rules for the use of riot control agents, are not so irrelevant for the implementation of the CWC.

    S. Batsanov

  2. ZHENG Xi (Brooke) says:

    Protest for real democratic elections in Hong Kong has entered into its third week. After Hong Kong police used tear gas and pepper spray at protesters during the first week protest, more Hong Kong people came down on the streets and joined the protest. Public criticism targets Hong Kong police for using tear gas and pepper spray at peaceful protesters. Yesterday, Hong Kong police used pepper spray at protesters again when trying to clear the roads. This post by Daniel Rietiker sheds light on the question whether it is legal for Hong Kong police to use tear gas and pepper spray at protesters.

    Rietiker offers another view of looking at the legality of use of tear gas and pepper spray. Based on European experiences, even though using tear gas and pepper spray for riot control is not prohibited in the CWC, protesters’ rights can still be protected under Art. 11 (the freedom of assembly) and Art. 3 (prohibition of torture) of European Convention on Human Rights. Hong Kong Basic Law also prohibits torture and ensures residents’ freedom of assembly (See Art. 27 & 28). If using tear gas and pepper spray is in violation of Art. 3 & 11of ECHR, one can make an argument that Hong Kong police using tear gas and pepper spray is in violation of the Basic Law.

    However, I agree with S. Batsanov that it is a mistake to jump to the conclusion that tear gas and pepper spray are not chemical weapons. The Organization for the Prohibition of Chemical Weapons stated that “States Parties have also agreed to create a verification regime for certain toxic chemicals and their precursors (listed in Schedules 1, 2 and 3 in the Annex on Chemicals to the CWC) in order to ensure that such chemicals are only used for purposes not prohibited.” (See This makes it clear that the Annex is created to prohibit use of certain chemicals for certain purposes instead of to serve as an exhausted list of all chemical weapons. Therefore, it is inaccurate to say that tear gas and pepper spray are not chemical weapons due to their absence in the Annex.

  3. Veronica Long Yin Lee says:

    I think it is interesting to reflect upon the use of tear gas from the Hong Kong point of view, since recently, on 28 September 2014, the HK police used 87 rounds of tear gas on protestors occupying Admiralty.

    According to, there are no specific laws that confer the use of tear gas by law enforcement agents in Hong Kong. Instead, the police rely on general power in the Public Order Ordinance or the Criminal Procedure Ordinance, both of which similarly confers the power to use such force as may be reasonably necessary. However, apparently the HK police have internal guidelines on the use of tear gas. These guidelines are not publicly available though. All of this provides a lot of uncertainty. When tear gas was used on 28 September 2014, many people argued that the protestors were peaceful and there were no acts of violence that required the police to the use tear gas. But what can the protestors do about it?

    With regards to human rights though, protesters’ of HK should similarly be protected under Article 3 of the HK Bill of Rights Ordinance (CAP 383), which provides that “no one shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment.” As to the interpretation of this provision, a HK court is “likely to apply proportionality reasoning” and determine if less intrusive means could have been used (see above link and HKSAR v Hung Chan Wa (2006) 9 HKCFAR 614). In this sense, this is similar to the ECtHR interpretation of Article 3 ECHR.

  4. Saroj Nair says:

    Thank you for this article.
    In the case of Abdullah Yasa & Others v Turkey, the ECHR has examined the question of use of tear gas grenades to disperse a non-peaceful gathering and has held such use as a violation of Article 3 of the Convention.
    The Court has distinguished the use of tear gas, pepper spray against demonstrators (as in Oya Ataman) from the use of tear gas grenades in the case of Abdullah Yasa observing that “the Abdullah case concerned not only the use of ‘tear gas’ but also the launching of a tear-gas grenade at the demonstrators. In fact, firing a grenade by means of a launcher generates the risk of causing serious injury, as in the instant case, or indeed of killing someone, if the grenade launcher is used improperly” Due to the dangerous nature of equipment issued, the Court, in the case of Abdullah has considered its case law on the use of potentially lethal force while considering its decision. Regarding the Oya Ataman case and other cases in the ECtHR which involved use of tear gas and pepper spray, the Court refers to the use of such agents and observes that such use in public order maintenance can cause unpleasant effects. But they are allowed to be used to maintain public order. The Court actually refers to the “mere fact” of using tear gas to disperse the unruly crowd (Oya Ataman) and says is is not violative of Article 3.
    In the Abdullah case, however, the Court also makes a reference to Article 2 of the Convention and has held that “unregulated and arbitrary action by state agents is incompatible with effective respect for human rights and that the same applied to Article 3”. The Court goes on to observe that “This means that police operations – including the launching of tear-gas grenades – should not only be authorised but should also be sufficiently delimited by domestic law, under a system of adequate and effective safeguards against arbitrary action, abuse of force and avoidable accidents”
    In the HK context, I would like to add that Section 46 (1) of the Public Order Ordinance in HK provides as a restriction on the use of force, it is provided that “the degree of force which may be so used shall not be greater than is reasonably necessary for” the purpose of dispersing the public gathering. Issue to be raised is whether the force used is reasonable and necessary. It also needs to be examined whether the use of force is proportional to the situation.

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