Many people in a position to judge have serious doubts about the justification for using 2-chlorobenzylidene malononitrile (CS) spray in police operations. A report by the Department of Health last year concluded that there were no health concerns over the employment of CS sprays if they were used under the proper conditions. However, a series of letters published in the British Medical Journal for July 1 have revealed considerable disquiet over the differences in estimates of the hazards involved in using a severe irritant within confined spaces, and where emergency action is called for and cool calculations may be out of the question.
After exposure to CS, contaminated clothing must be removed and those exposed given access to fresh air. In ordinary circumstances, symptoms of irritation will resolve spontaneously, and washing with soap and water is not recommended. However, irrigation of the eyes may be necessary to remove embedded particles of CS.
The spray used is a solution of CS solid in methyl isobutyl ketone, and much of the irritation produced when a face is sprayed can be attributed to the solvent, which irritates eyes and respiratory tract. Moreover, allergic contact dermatitis from repeated exposure may affect the user. Testing to assess this hazard adequately has not been performed. Altogether, the evidence for and against the safe use of CS spray has not been convincing. It is not surprising that some police authorities have refused to adopt this method of controlling violence.
A leading article in the same journal for February 10 by an ophthalmologist admitted that scientific data on the effects of CS were incomplete. However, it was suggested that if the preparation was used by properly trained enforcement officers, and exposed persons left the area immediately, there should be few significant long-term disabling effects. Some critics have not been convinced of the truth of this belief.