Surveillance into Crowd Control Agents

In response to your July 18 editorial,1Editorial“Safety” of chemical batons.Lancet. 1998; 352: 159Summary Full Text Full Text PDF PubMed Scopus (22) Google Scholar we draw your attention to our surveillance into crowd control agents (CCA)—eg, CS (orthochlorobenzylidene malonitrile) gas, mace (chloracetothenon, CNgas), and pepper spray—and possible adverse health effects after exposure. The National Poisons Information Service (London) (NPIS[L]) collates information concerning patient inquiries. In 1994, NPIS(L) was contacted about 327 casualties exposed to CCAs. In 1995, this figure rose to 654, in 1996, 810, and in 1997, 597. Enquiries to NPIS(L) are made in cases in which patient management advice for patients is required. It is likely that as the legal use of CS spray becomes more widespread, medical personnel will become familiar with the recommended treatment and will not seek advice from poisons centres.2Volans GN Wiseman HM Surveillance of poisons—the role of poison control centres.in: Eylenbosh WJ Noah NI Surveillance in health and disease. Oxford University Press, Oxford1988: 258Google Scholar Therefore, the data reported above, and on which our research and surveillance for 1998 are based, are likely to be only the tip of the iceberg. In 1996, various English police forces started to use CS sprays for their immediate short-lived effects. The police incapacitant used in England contains CS (5% concentration), the solvent methyl isobutyl ketone (MIBK), and a nitrogen propellant. A review of The English-language press found no reports of the use of MIBK, and CS in field conditions, although concerns have been expressed. Analysis of the CCA enquiries made to NPIS(L) in 1997 found that 454 (76%) were within 6 h of exposure and 143 (24%) were made after 6 h, with 11% of these latter enquiries made more than 36 h after exposure. Patients are not always exposed to CCA alone, and clinical effects may be due to other agents. The Table shows the differences in observed clinical effects occurring within 6 h of exposure and later. Crude analysis of the results suggests significant differences in dermal and gastrointestinal symptoms between the two periods. CS spray has been reported to cause erythematous contact dermatitis and allergic contact dermatitis with vesicles, blisters, and crusts.4Parnix-Spake A Theisen AJ Roujeau JC Revuz J Severe cutaneous reactions to selfdefense sprays.Arch Dermatitis. 1998; 20: 316Google Scholar CS was tested extensively by Himsworth3Himsworth H Black DAK Crawford I et al.Report of the inquiry into the medical and toxicological aspects of CS (orthochlorobenzylidine malonitrile), part I: and part II: enquiry into the medical situation following the use of CS in Londonderry on 13 and 14 August, 1969, and enquiry into toxocilogical aspects of CS and its use for civil purposes. HM Stationery Office, London1969Google Scholar, 4Parnix-Spake A Theisen AJ Roujeau JC Revuz J Severe cutaneous reactions to selfdefense sprays.Arch Dermatitis. 1998; 20: 316Google Scholar and others5Wheeler H Use and management of crowd control agents.Emergency Nurse. 1998; 5: 18-21Google Scholar and is generally shown to be safe and efficient with short-lived, self-limiting effects. However, the initial findings that we now report show that delayed adverse effects may be occurring as a result of CS spray. As a consequence of this crude analysis we are undertaking a further study to investigate adverse health effects after exposure to CCAs. We have followed up all CCA incidents reported to the NPIS(L) over 7 months (January to July, 1998) with three aims.TableTotal clinical effects of Crowd Control Agents in 1997 in 597 patients reported to the National Poisons Information Service (London)Clinical effects reported within 6 h of exposureNo (%)Clinical effects reported after 6 h of exposureNo (%)Crude differences between proportions p-value (95% CI)Ocular (irritation, lacrimation)191 (32)Ocular (irritation, corneal abrasions215 (36)0·2 (20·05 to 0·4)Dermal (rash, irritation, erythema, dermatitis)54 (9)Dermal (blisters, bullae, eczema, oedema)203 (34)<0·0001 (0·15–0·30)Respiratory (coughing, short of breath)30 (5)Respiratory (coughing, short of breath)24 (4)0·37 (0·02–0·11)Neurological (headache, drowsy)60 (10)Neurological (headache, drowsy)42 (7)0·02 (20·09 to 0·4)Cardiac (tachycardia, hypotension)24 (4)Cardiac (chest pain)36 (6)0·26 (20·04 to 0·14)Gastrointestinal (buccal irritation, vomiting)42 (7)Gastrointestinal (buccal irritation, vomiting)66 (11)<0·0001 (0·04 to 0·14)None48 (8)None6 (1)·Clinical effects not stated by inquirer119 (20)Clinical effects not stated by inquirer3 (0·5)·Other30 (5)Other3 (0·5)· Open table in a new tab First to determine short-term and medium-term clinical effects of exposure to CCAs; second, the proportion of enquiries in which police incapacitant spray was used; and third, whether the clinical symptoms resulting from exposure to police CS incapacitant (containing MIBK) are different from symptoms reported after exposure to other CCAs.