Themajority of thesematerials are alkylating agents that react with themoisture in the eyes to cause irritation. Under normal battlefield conditions, they do not pose a serious danger to the life of an exposed individual and do not produce any permanent injury. They are first generation chemicalwarfare agents andwere the first agents deployed inWorldWar I. Since the end of WorldWar I, numerous new agents have been developed, typically with greater irritating power and less toxicity. Under the general purpose criterion of the Chemical WeaponsConvention (CWC) theuse of irritating and lachrymatory agents is bannedduring a war. However, they may still be used by the military during operations other than war such as when responding to incidents of civil unrest. Lachrymatory agents are also used by police forces throughout the world to control rioters and disband unruly crowds. In some countries, agents can be purchased by individuals for personal protection.