Riot control agents: the tear gases CN, CS and OC—a medical review

Abstract

Introduction2-Chloroacetophenone (CN),o-chlorobenzylidene malonitrile (CS) and oleoresin capsicum (OC) are common riot control agents. While serious systemic effects are uncommon, exposure to high concentrations may lead to severe complications and even death. The aim of this narrative review is to summarise all main aspects of the riot control agents CN, CS and OC toxicology, including mechanisms of toxicity, clinical features and management.MethodsOVID MEDLINE and ISI Web of Science were searched for terms associated with CN, CS and OC toxicity in humans and those describing the mechanism of action, clinical features and treatment protocols.ResultsCN, CS and OC are effective lacrimating agents; evidence for toxicity, as measured by the threshold for irritation, is greatest for CN, followed by CS and OC. Typically, ocular and respiratory tract irritation occurs within 20–60 s of exposure. Ocular effects involve blepharospasm, photophobia, conjunctivitis and periorbital oedema. Following inhalation, effects may include a stinging or burning sensation in the nose, tight chest, sore throat, coughing, dyspnoea and difficulty breathing. Dermal outcomes are variable, more severe for CN and include dermal irritation, bulla formation and subcutaneous oedema. Removal from the contaminated area and fresh air is a priority. There is no antidote; treatment consists of thorough decontamination and symptom-directed supportive care. Ocular exposure requires thorough eye decontamination, an eye exam and appropriate pain management. Monitoring and support of respiratory function is important in patients with significant respiratory symptoms. Standard treatment protocols may be required with patients with pre-existing respiratory conditions. Dermal exposures may require systemic steroids for patients who develop delayed contact dermatitis.ConclusionsCN, CS and OC are effective riot control agents. In the majority of exposures, significant clinical effects are not anticipated. The irritant effects can be minimised both by rapid evacuation from sites of exposure, decontamination and appropriate supportive care.

Tear gas: an epidemiological and mechanistic reassessment

“…The decision by law enforcement to use tear gas during civil disorder is understandable, as CN, CS, and OC are effective RCAs and reduce the risk of injury to law enforcement personnel and demonstrators when used instead of physical force. 10,88 However, the massive increase in tear gas deployments worldwide, accompanied by advances in formulations and deployment technologies and the often-observed absence or disregard of evidence-based deployment rules and operating procedures, is of great concern. Epidemiological research on tear gas health effects is clearly deficient and has received little public support.…”

“…A 2003 analysis of several tear gases and incapacitants concluded that, on the basis of available toxicological evidence, commonly used tear gases have a large safety margin for life‐threatening or irreversible toxic effects . Another medical review published in 2013 concluded that, in the majority of exposures, significant clinical effects are not anticipated . However, there are debates surrounding the acceptability of tear gas use for riot‐control purposes, especially in the background of the recent massive use.…”

“…9 Another medical review published in 2013 concluded that, in the majority of exposures, significant clinical effects are not anticipated. 10 However, there are debates surrounding the acceptability of tear gas use for riot-control purposes, especially in the background of the recent massive use. Many believe the risks of tear gas exposure are understated and that perceived risks are based on insufficient human epidemiological and mechanistic data.…”

Accelerating Inflammation Resolution to Counteract Chemical Cutaneous Injury

“…Several treatment options, including the use of nonsteroidal anti-inflammatory drugs (NSAIDs), are published for HD and CS tear gas-induced cutaneous injury, with mixed outcomes (8, 18, 19). Despite their use as chemical warfare agents more than a century, there is no specific antidote for sulfur mustard or tear gas agent-induced cutaneous injuries (9). Although some therapeutic agents were tested for SM and CS tear agent-induced injuries, symptomatic treatment is the general line of treatment (8, 9, 18, 20-23).…”

Assessment of Potential Long Term Health Effects on Army Human Test Subjects of Relevant Biological and Chemical Agents, Drugs, Medications and Substances

“…318,319,320 An examination by Toprak and colleagues of 10 deaths in which riot-control agents were either the principal or contributory cause of death, showed that 7 of the lethal cases were associated solely with a pepper spray product. 321 Most of the serious complications, however, resulted from exposure to very high doses, 322 or from the subject being very close to the spray, smoke, or exploding canister. 315 Pre-existing health conditions, such as asthma, COPD, or cardiovascular disease; or interaction with prescribed medications or illegal drugs may also influence the development of severe injuries.…”