Agent CS, O-cholorobenzylidene malononitrile, is a white crystalline solid with a boiling point of 590ºF-599ºF (310ºC-315ºC), a flash point of 386ºF (197ºC), and a melting point of 194ºF (87ºC). It a vapor pressure of 3.4 × 10-5 at 20ºC and a vapor density several times heavier than air. CS is immiscible in water. Volatility is 0.71 mg/m³ at 77ºF (25ºC).
It has an odor that is biting and similar to pepper spray. Clouds produced by CS are white near the source for several seconds following the release. Usually, CS is disseminated by burning, exploding, or forming an aerosol. It may also be used in liquid form if dissolved into a solvent and aerosolized. CS acts rapidly compared to CN, and it is 10 times more potent, while it is also much less toxic. The LD50 for CS is approximately 200 mg/kg of body weight, or 14 g for a 70 kg person. CS has a TLV-TWA of 0.4 mg/m³, an ICt50 of 10-20 mg-min/m³, and an LCt50 of 61,000 mg-min/m³. The chemical formula for CS is C10H5ClN2, and the structure and molecular formula are shown in Figure 8.39.