Case Definition: Riot-Control Agents

Clinical description

Inhalational exposure to riot control agents may cause rapid onset of the following signs and symptoms: lacrimation, nasal or oropharyngeal irritation, choking sensation, cough, dyspnea and wheezing. Cutaneous exposures may produce skin irritation, rash, and chemical burns. (1-6)

Laboratory criteria for diagnosis

  • Biologic: No biologic marker for exposure to riot control agents is available.
  • Environmental: Detection of riot control agents in environmental samples. (7-10)

Case classification

  • Suspected: A case in which a potentially exposed person is being evaluated by healthcare workers or public health officials for poisoning by a particular chemical agent, but no specific credible threat exists.
  • Probable: A clinically compatible case in which a high index of suspicion (credible threat or patient history regarding location and time) exists for riot control agent exposure, or an epidemiologic link exists between this case and a laboratory-confirmed case.
  • Confirmed: A clinically compatible case in which air sampling or environmental laboratory tests have confirmed exposure.

The case can be confirmed if laboratory testing was not performed because either a predominant amount of clinical and nonspecific laboratory evidence of a particular chemical was present or the etiology of the agent is known with 100% certainty.

Additional resources

  1. Danto BL. Medical problems and criteria regarding the use of tear gas by police. Am J Forensic Med Pathol 1987;8:317-22.
  2. Fraunfelder FT. Is CS gas dangerous? Current evidence suggests not but unanswered questions remain. BMJ 2000;320:458-9.
  3. Hill AR, Silverberg NB, Mayorga D, Baldwin HE. Medical hazards of the tear gas CS: case of persistent, multisystem, hypersensitivity reaction and review of the literature. Medicine [Baltimore] 2000;79:234-40.
  4. Hu H., Fine J, Epstein P, Kelsey K, Reynolds P, Walker B. Tear gas—harassing agent or toxic chemical weapon? JAMA 1989;262:660-3.
  5. Thomas RJ, Smith PA, Rascona DA, Louthan JD, Gumpert B. Acute pulmonary effects from o-chlorobenzylidenemalonitrile “tear gas”: a unique exposure outcome unmasked by strenuous exercise after a military training event. Mil Med 2002;167:136-9.
  6. Varma S, Holt PJ. Severe cutaneous reaction to CS gas. Clin Exp Dermatol 2001;26:248-50.
  7. NIOSH. NIOSH manual of analytical methods [online]. 2003. [cited 2013 Apr 5]. Available from URL:
  8. OSHA. Sampling and analytical methods [online]. 2010. [cited 2013 Apr 5]. Available from URL: icon.
  9. FDA. Food: Laboratory methods [online]. 2013. [cited 2013 Apr 5]. Available from URL: icon.
  10. EPA. Selected analytical methods: chemical methods query [online]. 2013. [cited 2013 Apr 5]. Available from URL: icon.
Page last reviewed: April 4, 2018