Was it Lawful for the Police to Use Tear Gas on Protesters in Hong Kong?

What legal authority did the Hong Kong Police Force have to use multiple rounds of tear gas/smoke on protesters who were occupying Admiralty on 28 September 2014?  There are no legal provisions that authorise the specific use of tear gas by law enforcement agents.  The police must rely upon general powers in the Public Order Ordinance (Cap. 245) (POO) or the Criminal Procedure Ordinance (Cap. 221) (CPO).  Section 17(2) of the POO provides that any police office of or above the rank of inspector may disperse any public gathering if he reasonably believes that the gathering is likely to cause or lead to a breach of the peace.  To carry out this power, a police officer (of or above inspector rank) may give or issue such orders as he may consider necessary or expedient, and police officers may then "use such force as may be reasonably necessary" to disperse the public gathering.  Section 45 of the POO reiterates that any police officer "may use such force as may be necessary" to "prevent the commission or continuance of any offence under this Ordinance", to arrest, and "to overcome any resistance to the exercise of any of the powers conferred by this Ordinance".  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 (s. 46(1)).  Finally s. 101A(1) of the CPO confers the general power to "use such force as is reasonable in the circumstances in the prevention of crime", but this provision does not appear to add more to the powers under the POO.

However, to confer immunity on the police, s. 46(3) of the POO provides, "Any person who uses such force as may be necessary for any purpose, in accordance with the provisions of this Ordinance, shall not be liable in any criminal or civil proceedings for having, by the use of such force, caused injury or death to any person or damage to or loss of any property".  I highlight the qualifying words "as may be necessary...in accordance with the provisions of this Ordinance".  Thus the immunity will not apply where the reasonable necessity test cannot be met.  In this regard, it is important to note potential criminal liability under s. 22(1) of the Firearms and Ammunition Ordinance (Cap. 238).  Under this provision it is an offence to discharge any arms or ammunition in a manner likely to injure, or endanger the safety of, any person or property or with reckless disregard for the safety of others.  The definition of "arms" includes "any weapon for the discharge of any noxious liquid, gas, powder or other similar thing" (s. 2(1)).  Lawful authority and reasonable excuse are available defences, but these issues will largely turn on whether the police had used necessary and reasonable force.  Another issue for clarification is whether any of the tear gas/smoke used contained chemicals listed in the schedules of the Chemical Weapons (Convention) Ordinance (Cap. 578), which makes it an offence to "use a chemical weapon" (s. 5(a)).

Thus in deciding whether the police had legal authority to use tear case, the central issue is going to be whether the use of the tear gas was a degree of force "greater than" was reasonably necessary in the circumstances at the time.  In assessing this issue, it is important first to consider what guidelines and policies the police have adopted governing their use of tear gas in the public protest context.  The guidelines are important for two reasons.  First, they can be judged on their face to see if they contain sufficient strictures to comply with a reasonable necessity standard.  Second, if the guidelines are satisfactory, the actions of the officers on the ground can be assessed for compliance with the guidelines.  Beyond these guidelines, a court will likely apply proportionality reasoning as developed in Hong Kong's established human rights jurisprudence.  Whether there were less intrusive means to achieve the same objective would be relevant here (HKSAR v Hung Chan Wa (2006) 9 HKCFAR 614, [84]).  

It is said that the police have adopted internal guidelines on the use of tear gas but these guidelines do not appear to be accessible on the Police Force website.  When legislator the Hon. Margaret Ng in February 1996 asked the Secretary for Security about past tear gas use, the relevant internal guideline was summarised as follows: "(a) only the minimum level of force should be applied; (b) the use of force is to restore order quickly; (c) whenever possible, warning will be given; (d) force will not be used as a punitive measure; (e) force will cease immediately when the objective has been achieved ; (f) the degree of force permissible is determined by the senior officer present; and (g) the decision to use CS gas within buildings, if required, rests with the senior officer present."  More recently, when the Security Bureau was asked by legislators about the possible use of tear gas against Occupy Central protesters, the Under-Secretary for Security's reply was summarised as follows:

"Public order events held with or without prior notice given to the Police would be handled in accordance with established mechanisms and having regard to the specific circumstances of the case concerned.  When there was a breach of the law, the Police would, first of all, advise the persons concerned to comply with the law.   Warnings would be given where necessary.  Where the situation did not improve and there was a need for the Police to take resolute actions, clear instructions and warnings would be given and adequate time would be allowed for the persons concerned to comply with the instructions.  Regarding the use of force, it would not be used unless it was really necessary and the force used would be of minimum level to achieve its purpose."

From this one can derive the following list of factors relevant to assessing whether it was reasonably necessary for the police to use tear gas: (a) was only the minimum level of force used; (b) were sufficiently clear warnings given on each occasion; (c) was adequate time allowed on each occasion for the persons concerned to comply with the warning; (d) what was achieved by the means; (e) were less intrusive means reasonably available to achieve the same ends; (e) did a senior officer, who was present at the time, authorise each use?

While all the facts will need to be considered carefully before coming to any firm view, the scenes from the televised coverage showed (i) no clear acts of violence or rioting that necessitated the use of the tear gas - suggesting an excessive response, (ii) repeated uses of the tear gas appeared to surprise protesters - suggesting that either an inadequate warning was given or insufficient time was allowed for protesters to comply, (iii) throwing of tear gas canisters directly at protesters or into crowds - suggesting that not the minimum level of force was used, and (iv) quick regathering of protesters (after momentary dispersal) - suggesting that the tear gas achieved very little and certainly nothing that less intrusive means could not have achieved.  Thus it seems the Hong Kong Police Force have more than a clear case to answer to justify their use of force on the protesters.  Written by Simon N.M. Young.