38 CIRCUMSTANCES OF POTENTIALLY UNLAWFUL USE 7.6.4 Dazzling weapons shall not be used with intent to blind or where permanent blindness is a likely outcome. 7.7 WATER CANNON UTILITY AND DESIGN 7.7.1 Water cannon are vehicles designed to project water at a variety of pressures and in a variety of forms for the purposes of dispersing groups, protecting property or putting an end to violent behaviour. Chemical irritants, malodorants or other substances that are hazardous to health are sometimes mixed with the water used in water cannon. CIRCUMSTANCES OF POTENTIALLY LAWFUL USE 7.7.2 In general, water cannon should only be used in situations of serious public disorder where there is a significant likelihood of loss of life, serious injury or the widespread destruction of property. In order to meet the requirements of necessity and proportionality, the deployment of water cannon should be carefully planned and should be managed with rigorous command and control at a senior level.113 SPECIFIC RISKS 7.7.3 Water cannon should not be used against persons in elevated positions, where there is a risk of significant secondary injury. Other risks include hypothermia and cold-water shock in cold weather (especially if the water is not heated), and the risk of persons slipping or being forced by the jet against walls or other hard objects. Certain water cannon are indiscriminate in their effects, as they are unable to target individuals accurately. UNODC/OHCHR, Resource book on the use and force and firearms in law enforcement, p. 90. 113