CS gas is the common name for 2-chlorobenzalmalononitrile (also called o-Chlorobenzylidene Malononitrile) (chemical formula: C10H5ClN2), a "tear gas" that is used as a riot control agent. It is generally accepted as being non-lethal. CS was discovered by two Americans, Ben Corson and Roger Stoughton, at Middlebury College in 1928, and the chemical gets its name from the first letters of the scientists' surnames.[4] The compound is actually a solid at room temperature, though it is used as an aerosol.
Ah, CS gas, that chamber filled with you I shall never forget. Nor will I forget having to take off my mask to breath you in until I cried involuntarily. Nor will I forget the way you so auspiciously burned my knuckles long after I was out.
But I'd be crazy if I said I'd willingly do it again.