A/HRC/5/5 page 20 Several general principles governing the conduct of hostilities are relevant to the problem posed by the release of toxic and dangerous products during armed conflict, but there are also specific rules which address the issue of damage to the environment. 48. The general principles of the conduct of hostilities, namely distinction, proportionality and precautions, apply to attacks which could result in the release of toxic or dangerous products into the environment. The principle of distinction prescribes that parties to the conflict must at all times distinguish between civilian objects and military objectives, and that civilian objects must not be the object of attack. This principle is enshrined in article 52 of Additional Protocol I to the Geneva Conventions49 and State practice shows it to be a binding rule of customary international law, applicable to both international and non-international armed conflicts.50 Military objectives are defined as objects which by their nature, location or purpose make an effective contribution to military action and whose destruction offers a definite military advantage.51 This is particularly important in the context of attacks on industrial facilities, which could result in the release of toxic products. Indeed, most of these facilities are civilian in nature; in order for an attack to be legitimate, the destruction of the site must confer a definitive military advantage, for example a petroleum refinery which provides fuel to the military. If the site has no link to military operations and the objective of the attack is to destroy the economic capability of the State, the attack could be deemed to be illegal. It is important to note that the environment and its different elements (i.e. land, forests, oceans) are considered to be civilian objects. Elements of the environment, for example forest cover in a specific area, can be the object of attack only if it is used to conceal military objectives. 49. If an industrial facility deemed to constitute a military objective is to be targeted, the principle of proportionality must be respected by the parties to the conflict. An attack is prohibited if it is expected to cause incidental loss or damage which would be excessive in relation to the concrete and direct military advantage anticipated. Article 51, paragraph 5 (b) of Additional Protocol I codifies this principle and State practice shows it to be a binding rule of customary international law applicable to both international and non-international armed conflicts.52 An attack which could cause the release of toxic and dangerous products would violate this principle if the toxic products released could be expected to cause deaths or health problems in the civilian population or damage to civilian objects, including the natural environment, which would be excessive in relation to the military advantage gained from the destruction of the facility. 49 Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I), (8 June 1977). 50 Jean-Marie Henckaerts and Louise Doswald-Beck, Customary International Humanitarian Law (Cambridge, Cambridge University Press/International Committee of the Red Cross (ICRC), 2005), p. 25. 51 52 Additional Protocol I, art. 52, para. 2. Jean-Marie Henckaerts and Louise Doswald-Beck, Customary International Humanitarian Law (Cambridge, Cambridge University Press/ICRC, 2005), p. 46.