Rule 72. The use of poison or poisoned weapons is prohibited.
State practice establishes this rule as a norm of customary international law applicable in both international and non-international armed conflicts. This prohibition exists independently of the prohibition of chemical weapons (see Rule 74). Although the Geneva Gas Protocol was inspired by the existing prohibition of the use of poison, there is sufficient separate practice establishing a specific rule on poison and poisoned weapons.
The prohibition of poison or poisoned weapons is a long-standing rule of customary international law already recognized in the Lieber Code and the Hague Regulations.[1] “Employing poison or poisoned weapons” constitutes a war crime in international armed conflicts under the Statute of the International Criminal Court.[2]
The prohibition of poison or poisoned weapons is set forth in numerous military manuals.[3] The use of poison or poisoned weapons is an offence under the legislation of many States.[4] This prohibition is also supported by official statements and reported practice.[5] There is national case-law to the effect that the rule is part of customary international law.[6]
In their submissions to the International Court of Justice in the Nuclear Weapons case, several States recalled the prohibition of poison and poisoned weapons.[7] In its advisory opinion, the Court reaffirmed the customary character of the prohibition of the use of poison or poisoned weapons.[8]
The Statute of the International Criminal Court does not include the use of poison or poisoned weapons as a war crime in the sections dealing with non-international armed conflicts, and this issue was not openly debated during the Rome diplomatic conference. As a result, some implementing legislation of the Statute of the International Criminal Court limits to international armed conflicts the rule that the use of poison or poisoned weapons is a war crime.[9] However, the legislation of some States criminalizing the use of poison or poisoned weapons does apply to non-international armed conflicts.[10] Germany’s legislation states explicitly that the rule applies to both international and non-international armed conflicts.[11] The rule is also included in some military manuals which are applicable in or have been applied in non-international armed conflicts.[12] Several military manuals explain the prohibition of poison or poisoned weapons in armed conflicts on the grounds that they are “inhuman” and/or “indiscriminate”, an argument that is equally valid in non-international armed conflicts.[13] There is also reported practice from a number of States that supports the application of this rule in non-international armed conflicts.[14]
Practice is in conformity with the rule’s applicability in both international and non-international armed conflicts, as States generally do not have a different set of military weapons for international and non-international armed conflicts. There have been no confirmed reports of the use of poison or poisoned weapons in either international or non-international armed conflicts.[15] Allegations of such use have been rare.
No State has claimed that poison may lawfully be used in either international or non-international armed conflicts. The one example of limited contrary practice – a manual asserting that poisoning of drinking water and food is not forbidden if it is announced or marked – is not sufficient to deny the customary law character of this rule.[16]
Most States indicate that poison or poisoned weapons are prohibited without further detail. In its advisory opinion in the Nuclear Weapons case, the International Court of Justice stated that the terms “poison” and “poisoned weapons” “have been understood, in the practice of States, in their ordinary sense as covering weapons whose prime, or even exclusive, effect is to poison or asphyxiate”.[17] In their submissions to the International Court of Justice in the Nuclear Weapons case, the United Kingdom and the United States stated that the prohibition did not apply to weapons which could incidentally poison, but only to weapons that were designed to kill or injure by the effect of such poison.[18] This interpretation does not indicate that poison must be the primary or exclusive injury mechanism but that it must be an “intended” injury mechanism and is in keeping with the origin of the rule, namely, to prohibit the smearing of arrows with poison which would prevent recovery from the injury caused by the arrow.
The prohibition of the use of poison or poisoned weapons is understood as outlawing such practices as the smearing of bullets with poison or poisoning the food and drink of the adverse party. In their explanation of the application of this rule, several military manuals specify that the prohibition of poison extends to poisoning wells and other water supplies.[19]
[1] Lieber Code, Article 70 (cited in Vol. II, Ch. 21, § 4); Hague Regulations, Article 23(a) (ibid., § 2).
[2] ICC Statute, Article 8(2)(b)(xvii) (ibid., § 3).
[3] See, e.g., the military manuals of Argentina (ibid., § 12), Australia (ibid., §§ 13–14), Belgium (ibid., § 15), Bosnia and Herzegovina (ibid., § 16), Canada (ibid., §§ 17–18), Colombia (ibid., § 19), Dominican Republic (ibid., § 20), Ecuador (ibid., § 21), France (ibid., §§ 22–24), Germany (ibid., § 25), Indonesia (ibid., § 26), Israel (ibid., §§ 27–28), Italy (ibid., § 29), Kenya (ibid., § 30), Republic of Korea (ibid., § 31), Netherlands (ibid., §§ 32–33), New Zealand (ibid., § 34), Nigeria (ibid., §§ 35–37), Russian Federation (ibid., § 38), South Africa (ibid., § 39), Spain (ibid., § 40), Switzerland (ibid., §§ 41–43), United Kingdom (ibid., §§ 44–45), United States (ibid., §§ 46–51) and Yugoslavia (ibid., § 52).
[4] See, e.g., the legislation of Australia (ibid., §§ 54–55), Brazil (ibid., § 56), Canada (ibid., § 58), China (ibid., § 59), Democratic Republic of the Congo (ibid., § 61), Congo (ibid., § 60), Estonia (ibid., § 62), Georgia (ibid., § 63), Germany (ibid., § 64), Italy (ibid., § 65), Mali (ibid., § 66), Netherlands (ibid., §§ 67–68), New Zealand (ibid., § 69), Switzerland (ibid., § 70), United Kingdom (ibid., § 72), United States (ibid., § 73) and Yugoslavia (ibid., § 74); see also the draft legislation of Burundi (ibid., § 57) and Trinidad and Tobago (ibid., § 71).
[5] See, e.g., the statements of Iraq (ibid., § 80), Pakistan (ibid., § 91) and United States (ibid., §§ 98–99) and the reported practice of Bosnia and Herzegovina, Republika Srpska (ibid., § 77), India (ibid., § 79), Jordan (ibid., § 82), Kuwait (ibid., § 83), Malaysia (ibid., § 85), Norway (ibid., § 90), Philippines (ibid., § 92) and Rwanda (ibid., § 93).
[6] See, e.g., Japan, District Court of Tokyo, Shimoda case (ibid., § 75).
[7] See, e.g., the oral pleadings and written statements in the Nuclear Weapons case of Egypt (ibid., § 78), Marshall Islands (ibid., § 86), Mexico (ibid., § 87), New Zealand (ibid., § 89), Solomon Islands (ibid., §§ 94–95), Sweden (ibid., § 96), United Kingdom (ibid., § 97), United States (ibid., § 100) and Zimbabwe (ibid., § 101); see also the oral pleadings and written statements in the Nuclear Weapons (WHO) case of Malaysia (ibid., § 84) and Nauru (ibid., § 88).
[8] ICJ, Nuclear Weapons case, Advisory Opinion, §§ 80–82.
[9] See, e.g., the legislation of Australia (cited in Vol. II, Ch. 21, § 55), Canada (ibid., § 58), Congo (ibid., § 60), Mali (ibid., § 66), Netherlands (ibid., § 68), New Zealand (ibid., § 69) and United Kingdom (ibid., § 72); see also the draft legislation of Burundi (ibid., § 57) and Trinidad and Tobago (ibid., § 71).
[10] See, e.g., the legislation of the Democratic Republic of the Congo (ibid., § 61), Estonia (ibid., § 62), Germany (ibid., § 64), Switzerland (ibid., § 70) and Yugoslavia (ibid., § 74); see also the legislation of Italy (ibid., § 65), the application of which is not excluded in time of non-international armed conflict.
[11] Germany, Law Introducing the International Crimes Code (ibid., § 64).
[12] See, e.g., the military manuals of Australia (ibid., § 13), Bosnia and Herzegovina (ibid., § 16), Canada (ibid., § 18), Colombia (ibid., § 19), Ecuador (ibid., § 21), Germany (ibid., § 25), Italy (ibid., § 29), Kenya (ibid., § 30), Nigeria (ibid., §§ 35 and 37), South Africa (ibid., § 39) and Yugoslavia (ibid., § 52).
[13] See, e.g., the military manuals of Australia (ibid., §§ 13–14), Canada (ibid., § 17), France (ibid., §§ 23–24), Israel (ibid. , § 28) and United States (ibid., § 47) and the military manuals of Ecuador (cited in Vol. II, Ch. 20, § 52), Netherlands (ibid., § 72), New Zealand (ibid., § 73), South Africa (ibid., § 80), United Kingdom (ibid., § 85) and United States (ibid., §§ 87, 89, 91 and 93).
[14] See, e.g., the reported practice of Bosnia and Herzegovina, Republika Srpska (cited in Vol. II, Ch. 21, § 77), India (ibid., § 79) Philippines (ibid., § 92) and Rwanda (ibid., § 93).
[15] Reports of the use of chemical weapons and riot-control agents are addressed in Chapter 24.
[16] See Yugoslavia, Military Manual (cited in Vol. II, Ch. 21, § 52).
[17] ICJ, Nuclear Weapons case, Advisory Opinion (ibid., § 111).
[18] Written statements in the Nuclear Weapons case of the United Kingdom (ibid., § 97) and United States (ibid., § 100).
[19] See, e.g., the military manuals of Australia (ibid., § 14) (even if notice is given), Belgium (ibid., § 15) (even if notice is given), Canada (ibid., § 17) (even if notice is given), Colombia (ibid., § 19), Dominican Republic (ibid., § 20), Germany (ibid., § 25), Israel (ibid., § 28), Republic of Korea (ibid., § 31), Netherlands (ibid., § 32), Nigeria (ibid., § 36), South Africa (ibid., § 39), Spain (ibid., § 40), Switzerland (ibid., § 43), United Kingdom (ibid., § 44) (even if notice is given), United States (ibid., §§ 46 and 48–49) and Yugoslavia (ibid., § 52) (unless notice is given).