Is CS gas dangerous?

CS gas (2-chlorobenzylidene malononitrile) is one of the most commonly used tear gases in the world. Law enforcement agencies have found this agent invaluable when faced with combative suspects, for riot control, and for alleviating hostage and siege situations. They use it to help control individuals or groups without the need for lethal force. The chemical was used for crowd control as early as the 1950s, but not until the mid-1960s did it come into common use in several countries. In Britain there has been persistent concern about the use of CS gas in the media, numerous complaints to the Police Complaints Authority, and an editorial two years ago in the Lancet that called for a moratorium on the use of CS tear gas.1 This editorial was unusual in calling for a moratorium on an agent used widely for decades with little data on permanent damage. Nevertheless, it did correctly identify the need for some further studies, as did a …