Effects on Man of Drenching with Dilute Solutions of o -Chlorobenzylidene Malononitrile (CS) and Dibenz(b.f)-1:4-Oxazepine (CR)

As one part of a safety evaluation of sensory irritant Materials, observations were made on volunteers drenched with aqueous solutions containing up to 0·005 per cent o-chlorobenzylidene malononitrile (CS) or 0·0025 per cent dibenz(b.f)-1: 4-oxazepine (CR). Such solutions affected the eyes and skin. In the eye there was immediate discomfort, blepharospasm and profuse lachrymation of a few minutes duration; the effects were similar with CS and CR. Skin sensations, described as stinging or burning, appeared later, lasted for up to 20 minutes, and were most severe on the face, back of the trunk and, in males, the external genitalia; the intensity and duration were greater with CR than with CS. During the period of intense skin irritation a rise in blood pressure was measured. Exercise during this period did not produce further increases in blood pressure. The nature of the blood pressure rise is discussed, and evidence presented that it was probably due to the intensely uncomfortable nature of the experience.