Three common types of riot control agents (rcas) are:

Three common types of Riot Control Agents (RCAs) are lacrimators, sternutators and vomiting agents. The first causes tears and other eye irritations. The second, sernutators, affects the lungs and upper respiratory tract, which makes most often causes a reaction of sneezing. The final RCA is self-explanatory and induces vomiting.

Since the time there were born it depends, there's fun violence, abuse, r@pe, kidnappings, threats, hostages ect.