88 Resource book on the use of force and firearms in law enforcement In public order situations, using tear gas is clearly placed at the far end of the scale of force, as it is difficult to target specific people and therefore it is likely to affect and harm uninvolved bystanders. By its very nature it is not able to discriminate, and as a result all bystanders are affected. Indeed, it was noted by the Special Rapporteur on the rights to freedom of peaceful assembly and of association that “gas does not discriminate between demonstrators and non‑demonstrators, healthy people and people with health conditions.” He also warns against any modification of the chemical composition of the gas for the sole purpose of inflicting severe pain on protestors and, indirectly, bystanders.188 For this reason some police agencies do not use tear-gas grenades as they do not deem it an appropriate law enforcement tool due to its inability to discriminate, as well as the risk of escalation, and of other harm caused by crowds fleeing. NATIONAL EXAMPLES ON THE USE OF TEAR GAS The National Police Manual in the Philippines has an explicit provision that tear gas and water cannon can “only be used [for rallies and demonstrations] when the public assembly is attended by actual violence or serious threats of violence, or deliberate destruction of property”.a In Tunisia, there is a similar requirement that only the commander in charge (le commandant d’opération) can decide to deploy tear gas. The commandant d’opération at the scene shall make an assessment of the scene to decide whether the use of tear gas would be necessary, proportionate and effective, and recommend/order the use to the operational commander. After the event the commander-incharge must check that the site has been properly and completely cleared of the gas. a See Philippines National Police Manual, 2010, Rule 23, Section 3 and 10; Rule 24, Section 2. Guidelines for use of tear-gas grenades The OHCHR Manual on Human Rights Training for Law Enforcement Officials (2017) recommends, in order to limit the risks of injuries to those targeted, that law enforcement officers (LEOs) always consider the following:189 • Never use a higher concentration of riot control agents than is approved according to international standards to remain less-lethal. • Never use riot control agents in confined spaces or expose the same targets to riot control agents several times during a short time period. • Never use riot control agents against persons who are restrained or confined to a place where they have no escape routes from the chemical. • Never fire riot control agents from hand held launchers directly towards a person. Many persons have died or been seriously injured from the impact of a riot control agent container. • Never use riot control agent grenades in wide areas against larger groups, unless the level of violence has reached such a high level that LEOs cannot address the threat by directly targeting violent persons only. • Always decontaminate a detained person who has been exposed to a riot control agent. 188  See Report of the Special Rapporteur on the rights to freedom of peaceful assembly and of association, A/HRC/20/27, 21 May 2012, para. 35. 189  OHCHR, Human Rights and Law Enforcement, A Manual on Human Rights Training for Law Enforcement Officials, 2017, chapter 5. See also Amnesty International and Omega Research Foundation, The human rights impact of less lethal weapons and other law enforcement equipment, 2015.