22 6.1.4 Disorientation or distraction devices, such as pyrotechnic flash-bang grenades, are designed to give a warning or to help facilitate a safe arrest, especially in the course of high-risk operations. The use of pyrotechnic flashbang grenades directly against a person would be unlawful as it could cause serious burn or blast injuries and, in certain cases, there could even be a risk of fragmentation. 6.2 IN CUSTODIAL SETTINGS 6.2.1 Individuals in custodial settings are especially vulnerable to injury from lesslethal weapons.69 In accordance with the United Nations Standard Minimum Rules for the Treatment of Prisoners (the Nelson Mandela Rules), all detainees shall be treated with the respect due to their inherent dignity and value as human beings.70 No detainee shall be subjected to and all detainees shall be protected from torture or other forms of cruel, inhuman or degrading treatment or punishment. No circumstances whatsoever may be invoked as a justification for such treatment or punishment. The safety and security of detainees, staff and visitors shall be ensured at all times.71 6.2.2 Regulations for custodial settings should clearly state which less-lethal weapons and related equipment are authorized for use, by whom, and what types of force may be used. They should establish rules and procedures for use that comply with international standards. Law enforcement officials shall be prohibited from carrying personal weapons in custodial settings. Persons in custody should have access to applicable regulations governing the use of force. 6.2.3 Custodial staff shall not use force against persons in custody, except as a last resort, and only in cases involving self-defence, attempted escape or active/ passive physical resistance to an order based on law or regulations.72 In any event, the force used shall be proportionate to the threat posed by the See for example E. Hoffberger-Pippan, “Non-Lethal Weapons and International Law: A ThreeDimensional Perspective”, PhD Thesis, Johannes Kepler University, Linz, Austria, 2019, §III (A)(2). 70 See also International Covenant on Civil and Political Rights, article 10. 71 Nelson Mandela Rules, rule 1. 72 Ibid, rule 82 (1). See also United Nations Rules for the Protection of Juveniles Deprived of their Liberty, adopted by the General Assembly in its resolution 45/113 on 14 December 1990, annex, para. 65. 69