Mechanism of Toxicity of Injected CS Gas

Abstract

IN 1928 Corson and Stoughton¹ prepared a number of benzylidene malononitriles, including 2-chlorobenzylidene malononitrile (CS). Although these authors were primarily concerned with the isolation and chemistry of the condensation products of malononitrile and various aldehydes, sternutatory and irritant properties on the part of some of the compounds were reported. CS is now the active material in a wide range of devices used against civil disturbances and in war (see, for example, refs. 2–6). Benzylidene malononitriles are reactive substances, and have been shown to form adducts with amines^7–10, n-butanethiol^10–12, Grignard reagents^13,14, hydrazoic acid¹⁵, hydrogen cyanide^1,15–17, salts of certain transition elements^18,19, and trialkylphosphines^20–22. Reactions also occur with hypochlorite^23–24, water^1,9,17,25,26, oxidizing¹ and reducing^7,27,28 agents. Certain aspects of the physiological effects^{2,7,8,29–32} and toxic properties^23,33–38 of CS have also been studied. We here describe a brief investigation into the mechanism of toxicity of CS. Because elevated levels of thiocyanate have been found in the blood of human patients treated with 4-nitrobenzylidene malononitrile³⁹, and because malononitrile is one of the products when CS is hydrolysed in aqueous ethanol⁹, the toxicities of cyanide and malononitrile have also received attention.