A/HRC/5/5 page 21 50. In any event, the parties to the conflict are bound to respect the principle of precaution. This entails the planners of an attack adopting a number of measures designed to avoid, or limit to the maximum extent, incidental losses in the civilian population or damage to civilian objects. The principle of precaution is codified in articles 57 and 58 of Additional Protocol I and State practice shows it to be a binding rule of customary international law applicable to both international and non-international armed conflicts.53 The measures which can be adopted to comply with this principle include determining that the target is indeed a military objective; that the attack will respect the principle of proportionality; that the means used to attack the target will be the one least likely to cause incidental damage; and that another target, which will afford an equivalent military advantage while posing a lesser threat to the civilian population or objects, is not available. In addition to precautions in attack, parties to the conflict must also take precautions against the effect of attacks. In order to minimize the threat to life and health posed by a possible release of toxic or dangerous products, this could mean avoiding placing potential military objectives within or near densely populated areas. Although this might not be possible for dual use installations, a State would be under obligation, for example, not to place military fuel stocks in an urban area. Finally, the parties to the conflict must give advance warning of an attack which might affect the civilian population, unless the circumstances do not permit. While the Special Rapporteur very strongly discourages parties to an armed conflict from attacking facilities containing toxic and dangerous products under any circumstances, he calls upon them to comply, in all such cases, with the obligation to give advance warning. 51. International humanitarian law also contains several specific limitations on the conduct of hostilities which are applicable to the particular issue of release of toxic and dangerous products. Additional Protocol I and customary international law contain general protections for the environment. In particular, it is prohibited to cause widespread, long-term and severe damage to the natural environment.54 There are two aspects to this rule: not only does it prohibit the use of methods and means of warfare which may cause such damage, it also creates a positive obligation to the effect that care should be taken in warfare to protect the environment from this type of severe damage. Article 55 of Additional Protocol I specifically mentions prejudice to the health and survival of the population as a consequence which this prohibition seeks to avoid. This limitation to the conduct of hostilities is particularly applicable to the widespread use of defoliants and other herbicides, as well as to the targeting of facilities which could release a significant volume of toxins capable of severely affecting a large area for a long period. It is important to note that this prohibition is absolute and causing such damage cannot be justified by military necessity. 53 54 Ibid. Articles 35, para. 3 and 55, para. 1 of Additional Protocol I; Jean-Marie Henckaerts and Louise Doswald-Beck, Customary International Humanitarian Law (Cambridge, Cambridge University Press/ICRC, 2005), p. 151.