Rule 121. Location of Internment and Detention Centres
Rule 121. Persons deprived of their liberty must be held in premises which are removed from the combat zone and which safeguard their health and hygiene.
Summary
State practice establishes this rule as a norm of customary international law applicable in both international and non-international armed conflicts. This rule is reinforced by the fundamental guarantee that civilians and persons hors de combat must be treated humanely (see Rule 87).
International armed conflicts
The rule according to which persons deprived of their liberty must be held in premises which are removed from the combat zone and which safeguard their health and hygiene is provided for by the Third and Fourth Geneva Conventions.[1] 
Safe, healthy and hygienic conditions of detention are required by numerous military manuals.[2]  These requirements are also included in the legislation of several States.[3]  In a diplomatic note in 1991, the United States assured Iraq that it would not expose Iraqi prisoners of war to danger but would safeguard them against harm during combat operations.[4]  In a report to the UN Security Council on operations in the Gulf War, the United States alleged that Iraq had exposed coalition prisoners of war to the dangers resulting from combat “in blatant disregard for international law”.[5] 
Non-international armed conflicts
Additional Protocol II requires that detainees be held in healthy and hygienic conditions and that places of internment and detention not be located close to the combat zone.[6]  In addition, this rule is contained in other instruments pertaining also to non-international armed conflicts.[7] 
This rule is contained in several military manuals which are applicable in or have been applied in non-international armed conflicts.[8]  The legislation of a number of States requires that safe, healthy and hygienic conditions of detention be provided.[9] 
The ICRC has called on parties to both international and non-international armed conflicts to respect the rule that detainees be held in safe, healthy and hygienic conditions.[10] 
It should be noted that poor conditions of detention may amount to inhuman treatment (see commentary to Rule 90).
No official contrary practice was found with respect to either international or non-international armed conflicts.

[1] Third Geneva Convention, Article 22, first paragraph (cited in Vol. II, Ch. 37, § 191) and Article 23, first paragraph (ibid., § 192); Fourth Geneva Convention, Article 83, first paragraph (ibid., § 193) and Article 85, first paragraph (ibid., § 194).
[2] See, e.g., the military manuals of Argentina (ibid., §§ 198–199), Australia (ibid., § 200), Belgium (ibid., §§ 201–202), Cameroon (ibid., § 203), Canada (ibid., § 204), Colombia (ibid., § 205), Croatia (ibid., § 206), France (ibid., §§ 207–209), Germany (ibid., § 210), Israel (ibid., § 211), Italy (ibid., § 212), Madagascar (ibid., § 213), Mali (ibid., § 214), Netherlands (ibid., § 215), New Zealand (ibid., § 216), Senegal (ibid., § 217), Spain (ibid., § 218), Switzerland (ibid., § 219), United Kingdom (ibid., §§ 220–221) and United States (ibid., §§ 222–223).
[3] See, e.g., the legislation of Azerbaijan (ibid., § 224), Bangladesh (ibid., § 225), Ireland (ibid., § 226) and Norway (ibid., § 227).
[4] United States, Department of State, Diplomatic Note to Iraq (ibid., § 229).
[5] United States, Letter to the President of the UN Security Council (ibid., § 230).
[6] Additional Protocol II, Article 5(1)(b) and (2)(c) (adopted by consensus) (ibid., § 195).
[7] See, e.g., Comprehensive Agreement on Respect for Human Rights and International Humanitarian Law in the Philippines, Part IV, Article 4(6), (ibid., § 196); UN Secretary-General’s Bulletin, Section 8(b) (ibid., § 197).
[8] See, e.g., the military manuals of Argentina (ibid., § 199), Cameroon (ibid., § 203), Canada (ibid., § 204), Colombia (ibid., § 205), Croatia (ibid., § 206), Germany (ibid., § 210), Italy (ibid., § 212), Madagascar (ibid., § 213), Netherlands (ibid., § 215), New Zealand (ibid., § 216), Senegal (ibid., § 217) and Spain (ibid., § 218).
[9] See, e.g., the legislation of Azerbaijan (ibid., § 224).
[10] See, e.g., ICRC, Press Release No. 1504 (ibid., § 236), practice in the context of a non-international armed conflict (ibid., § 237), Memorandum on Respect for International Humanitarian Law in Angola (ibid., § 238) and Memorandum on Compliance with International Humanitarian Law by the Forces Participating in Opération Turquoise (ibid., § 239).