The Irritant Potential of Dilute Solutions of ortho‐Chlorobenzylidene Malononitrile (CS) on the Eye and Tongue

Abstract: Median threshold concentrations for the riot control agent o-chlorobenzylidene malononitrile (CS) to produce blepharospasm were found to be 5.9 × 10−5 M for the rabbit, 2.2 × 10−5 M for the guinea pig and 3.2 × 10−6 M for man. The threshold concentration to produce sensation on the human cornea was 7.3 × 10−7 M. A dose-response relationship was demonstrated. Extrapolation of log-probit plots for sensation on the human eye suggest that 2.7 × 10−5 M would be incapacitating. The median threshold concentration of CS required to produce sensation on the human tongue was 6.8 × 10−6 M; a concentration 9.4 times that required to produce eye sensations. A dose-response relationship on the tongue was demonstrated. The use of irritant tests, species variations in response, and the effects of solvents on the response are discussed.