Riot Control Agents

Issues in Toxicology, Safety & Health

Eugene J. Olajos, Woodhall Stopford M.D., Woodhall Stopford, M.D.

• Publisher: CRC Press
• Year: 2004
• Print ISBN: 9780415299022
• eBook ISBN: 9781134424931
• Topic: Law
• Subtopic: Toxicology
• Index: Law

The proliferation and sophistication of riot control chemicals mean that all parties need to understand the responsible use and effects of such compounds. This book provides practical information on the history, chemistry, and biology of riot control agents and discusses their biological actions, risk assessment issues, and recent technical develop

CHAPTER 1
Introduction and Historical Perspectives
EUGENE J. OLAJOS¹ AND WOODHALL STOPFORD²

¹ US Army Edgewood Chemical and Biological Center, Aberdeen Proving Ground, Maryland

² Division of Occupational and Environmental Medicine, Duke University Medical Center, Durham, North Carolina

1.1 INTRODUCTION

Techniques have been available for many years to deal with civil disturbances and uncontrolled demonstrations – in particular methods involving the utilization of irritant chemical substances. Modalities used in riot control situations are intended to deter, disperse or render temporarily incapacitated those involved in disturbances using minimal physical intervention and reduction of face-to-face conflict between law enforcement or responding personnel and demonstrators. Nonchemical means of riot control and crowd dispersion include the use of water cannon and plastic/rubber bullets – other approaches such as the use of low friction polymers to hinder movement has been suggested as a potentially useful riot control technique. Chemically based means of riot control and crowd dispersion, either in use, under development, or proposed, include the following types of chemical intervention: (1) peripheral sensory irritants (i.e. “tear gases”, oleoresin capsicum (OC, “pepper spray”), (2) dyes, pigments or fluorescent marking paints, (3) persistent obnoxious odor causing substances (malodorants), and (4) nonirritant obscuring smokes (Swearengen, 1966; Pearlman, 1969; Deane-Drummond, 1975; Ballantyne, 1977). Riot control methods are diverse and some have obvious toxicological, medical, operational, or sociological disadvantages and have not been utilized in civil disturbances. Of the aforementioned chemically based riot control technologies, devices/systems based on the peripheral sensory irritants also referred to as “lacrimators,” “harassing agents,” “tear gases” (i.e. chloroacetophenone (CN), o-chlorobenzylidene malononitrile (CS)), and “inflammatory agents” (i.e. OC), constitute the mainline riot control agents (RCAs) used by law enforcement and military personnel. A recently developed product for law enforcement use (i.e. CapTor^®) contains nonivamide (“synthetic capsaicin”) as the active ingredient and is considered by the manufacturer as an improvement over established defense sprays containing CS, CN, or OC.

“Riot control agents” is the collective term used to describe a divergent group of compounds that have been developed for use by law enforcement and military personnel as well as for personal protection. These compounds have been referred to as lacrimators or as “harassing agents” and are commonly called “tear gases” – the latter term a misnomer since these compounds are not gases. Reference to these compounds as “harassing agents” is based on chemically induced localized, uncomfortable sensations (e.g. lacrimation, stinging, burning sensation, rhinorrhea, tightness in the chest) with associated reflexes. The effectiveness of these compounds in crowd control/crowd dispersion derives from their properties as extremely potent lacrimators and highly effective irritants of the mucous membranes and skin. RCAs have been described as nonlethal. Characteristics common to RCAs include: a rapid onset of effect(s), a relatively short duration of action following cessation of exposure and (3) a relatively high safety margin between an irritating dose and the one associated with risk of irreversible effects or death. A synopsis of RCAs currently in use as well as that representative of the early RCAs is given in Table 1.1. The riot control agent CN is still manufactured and used to a limited extent. CS is still frequently employed as a RCA; however, OC (“pepper spray”) is rapidly gaining widespread use among law enforcement personnel. RCAs also constitute the active ingredient(s) of self-defense sprays (“aerosol subject restraints” (ARSs)) – products that are widely used by law enforcement agencies and for personal protection. A discussion on personal defense sprays follows the overview on RCAs as utilized in quelling civil disturbances and in “peacekeeping” operations by law enforcement agencies and in various military applications.

As previously mentioned, RCAs comprise a diverse group of compounds. A brief synopsis of the physico-chemical properties of modern RCAs is presented in Table 1.2. For a detailed description and discussion related to the chemistry of RCAs the reader is referred to Chapter 3 by Katz and Salem.

Riot control agents are highly potent sensory irritants, which elicit acute site-specific physiological actions affecting the eyes, the pulmonary system, and skin (refer to Figure 1.1). Exposure to RCAs may occur via inhalation, dermal, or oral routes or a combination of these exposure pathways. Pharmacologically, these chemicals interact with sensory nerve receptors associated with mucosal surfaces and the skin at the site of contamination, producing localized discomfort or pain with associated reflexes. Thus, ocular irritation, representative of such responses, results in ocular pain (warning) and excess reflex lacrimation and blepharospasm (protection). Riot control agents act primarily on the eye, which is the most sensitive target organ. Immediate tearing, conjunctivitis, with concomitant blepharospasm (uncontrollable closure of the eyelids), burning sensation, and pain are characteristic symptoms on exposure. Moreover, when dispersed into the eyes, RCAs can cause temporary blindness due to copious lacrimation, which induces disorientation and fear. Although intense lacrimation is a common reaction on exposure to RCA, it must be recognized that these compounds can also elicit varying physiological responses. Thus, respiratory tract and gastrointestinal irritation (i.e. shortness of breath, coughing, wheezing, nausea, and vomiting) are additional manifestations of RCA exposure. It is important to recognize from the biological perspective that RCAs can produce some or all of the effects to a greater or lesser extent. Modern day RCAs are highly effective at low doses and possess low acute toxicity (see Table 1.2). The lethal quantity of CS is estimated to be about 2,600 times as great as the dosage required to produce temporary disabling (Danto, 1987). The margin-of-safety is large – the amount causing an intolerable effect is many times less than the amount producing an adverse effect. Permanent adverse effects usually do not accompany RCAs; however, the risks for deleterious effects, long-term effects, or even lethality increase with higher exposure levels and/or with greater exposure times. The response is concentration-dependent and ceases on removal of the sensory irritant stimulus. RCAs should possess low acute toxicity and have toxicological and chemical properties that ensure minimal risks. Ideally, in riot control situations as well as in situations other than under riot circumstances, these substances produce “harassing effects” that are relatively benign with a low incidence of casualties and adverse health effects. Generally, it can be stated that modern RCAs possess high safety ratios and deemed safe when used in accordance with prudent practices.

TABLE 1.1
RCAs and lacrimators

TABLE 1.2
Physico-chemical and biological properties of common RCAs

Figure 1.1: Acute site-specific pharmacology/toxicology of RCAs.

1.2 DISSEMINATION

“Peacekeeping” operations vary markedly from those involving only a few individuals to those involving crowds that may comprise large numbers of individuals. Thus, the mode of delivery of RCAs varies and dependent on the situation/scenario. RCAs may be disseminated by pyrotechnic means (i.e. canisters, tear gas grenades) giving rise to an aerosol of irritant. A convenient way of producing an aerosol from relatively thermo stable compounds such as CN, CS, or CR is to formulate the active ingredient with a pyrotechnic base (i.e. chlorate and lactose). Pyrotechnic dissemination results in volatilization of the RCA, which condenses in cooler air producing a respirable aerosol. A description of the technology of the various devices for producing irritant smokes has been described by Swearengen (1966). Ballantyne (1977) in his review of RCAs discussed the mode of use and had categorized devices available for law enforcement and personal protection as powder formulation devices and liquid formulation in spray canisters. Powder formulation devices were used in the past and were associated with injury to the eyes – these devices are seldom used in present-day law enforcement operations and personal protection. Riot control agents CN, CS, and OC may also be dispersed as aerosols via pressurized containers consisting of the RCA in a carrier/solvent and propellant. Modern “aerosol can” technology has provided a safe and convenient method for the dissemination of RCAs present in liquid formulations. Macleod (1969) has provided a description of the differences between thermal and solvent spray devices. Ditter and Heal in Chapter 2 provide a historical overview of dissemination technologies developed for RCAs as well as an up-to-date account of contemporary dissemination technologies. Pyrotechnic devices have application in crowd control and in “peacekeeping” operations, whereas dispersion via pressurized containers have found use in law enforcement applications as well as for personal protection.

1.3 HISTORICAL PERSPECTIVES

Lacrimatory and irritant compounds, many of which are listed in Tables 1.3 and 1.4 have a history dating from the First World War. Many of these chemicals have been deployed as chemical warfare agents and others (e.g. CN, CS, DM) have been used in riot control and civil disturbances and in military exercises and training. Tear gases of the First World War included acrolein (papite), bromoacetone (BA, B-stoff), bromobenzyl cyanide (CA, BBC), chloroacetone (A-stoff), xylyl bromide (T-stoff), and diphenylaminochloroarsine (DM). Chloropicrin (trichloronitromethane), a well-known chemical prior to the First World War, was used both as a harassing agent and lethal war gas. In fact, chloropicrin was one of a number of lethal agents – the others being chlorine, phosgene, and trichlorethylchloroformate. The highly potent lacrimator, BA, was the most widely utilized lacrimatory agent in the First World War. Xylyl bromide, also known as T-stoff, was also employed. Another highly potent lacrimatory compound developed prior to the 1920s was ethyl bromoacetate. Swearengen, referred to ethyl bromoacetate as the first RCA – based on its use in Paris in 1912 (Swearengen, 1966). Moreover, according to Royer and Gainet (1973), ethyl bromoacetate was purported to have been used in the 1970s in riot control situations.

TABLE 1.3
Tear gases (lacrimatory compounds)

TABLE 1.4
Tear agents utilized as war gas in the First World War

Vomiting agents, which are arsenic-based compounds, were also developed during the latter stages of the First World War and included: diphenylchlorarsine (DA), diphenylcyano-arsine (DC), and diphenylaminochloroarsine (DM, adamsite). These compounds in addition to causing emesis also produce severe irritation to the eyes, nose, and throat. The vomiting agent adamsite, also classified militarily as a sternutator, was utilized as an RCA after the war. Utilization of these compounds in closed and confined spaces resulted in rapidly attained incapacitating dosages and an elevated risk for fatalities. The lacrimatory agent, CA, also known as camite, was a replacement for arsenical vomiting agents. CA and related compounds were early RCAs. These compounds were developed at the end of the First World War initially to supplement and subsequently to replace the vomiting agents. CA is a potent eye and respiratory irritant with an immediate onset of action. It is characterized as possessing appreciable toxicity.

CA became obsolete in the 1920s with the introduction of CN. Although CN was discovered over a century ago, it was not used in the First World War. In the late 1920s, CN was utilized in French colonies to break up civil disorders, and was adopted worldwide for use by law enforcement agencies soon thereafter. For many years, CN was the most widely used RCA by civil and military authorities as well as for personal defense. In contemporary terminology, CN is referred to as “mace” (Mace^®), a liquid mixture containing CN in kerosene hydrocarbons and 1,1,1-trichloroethane and Freon^® propellant (i.e. 1,1,2-trichloro-1,2,2-trifluoroethane). Mace^® is the brand name for a specific product containing CN and should not be used as a generic term for all defense spray products. CN was also formulated with various solvents (e.g. carbon tetrachloride, benzene) to yield a highly irritating mixture. The agent CNB (CN, carbon tetrachloride, benzene) was once used as a training agent. Another CN formulation (i.e. CNS – a mixture of CN, chloroform, chloropicrin) was developed not so much as a lacrimatory agent but as a non-arsenical vomiting agent. CN is still produced; however, it has limited application in present-day law enforcement and “peacekeeping” operations.

The emergence of chemicals such as CN into law enforcement operations stemmed from military experience with harassing agents. However, many of the military “harassing agents” were not suitable for law enforcement use due to concerns associated with the likelihood of causing fatalities and/or total incapacitation. Consequently, the development of modern RCA has been driven by requirements to develop safe and effective compounds that could be easily disseminated. It is important to note that RCAs are intended to temporarily disable – the intense irritant effects producing a varying degree of incapacitation. An in-depth discussion on incapacitation is not intended since several sources, which provide detailed discussions on the “incapacitating” effects of RCAs, are available in the literature (e.g. Rothschild, 1964; Cookson and Nottingham, 1969; Rose and Smith, 1969; Jones, 1971). By the end of the First World War, a systematic search of compounds suitable for temporary incapacitation and riot control was in place. Despite a considerable amount of research endeavor on a substantial number of prospective compounds, interest soon focused on CN and DM. In later years, research efforts centered on the development of CS and dibenz[b,f]1:4-oxazepine (CR) as RCAs. Between the First and Second World War, CN and DM had become the harassing agents of choice despite the early use of CA as an RCA. There existed considerable stockpiles of CN and DM at the time of the Second World War. Although DM was employed as an RCA, CN superseded DM as an RCA.

Despite the widespread use of CN, dissatisfaction with the potency and chemical stability of CN prompted research initiatives to develop alternative RCAs. CS, which manifested greater potency and lower toxicity, was the replacement for CN. Although CS was synthesized...

Table of contents

• COVER PAGE
• TITLE PAGE
• COPYRIGHT PAGE
• LIST OF CONTRIBUTORS
• PREFACE
• CHAPTER 1: INTRODUCTION AND HISTORICAL PERSPECTIVES
• CHAPTER 2: APPLICATION AND USE OF RIOT CONTROL AGENTS
• CHAPTER 3: SYNTHESIS AND CHEMICAL ANALYSIS OF RIOT CONTROL AGENTS
• CHAPTER 4: BIOCHEMISTRY, BIOLOGICAL INTERACTIONS, AND PHARMACOKINETICS OF RIOT CONTROL AGENTS
• CHAPTER 5: RIOT CONTROL AGENTS AND ACUTE SENSORY IRRITATION
• CHAPTER 6: PHARMACOLOGY/TOXICOLOGY OF CS, CR, CN, FORMULATIONS, DEGRADATION PRODUCTS, CARRIERS/SOLVENTS, AND PROPELLANTS
• CHAPTER 7: PHARMACOLOGY/TOXICOLOGY OF OLEORESIN CAPSICUM, CAPSAICIN, AND CAPSAICINOIDS
• CHAPTER 8: CHRONIC TOXICITY OF RIOT CONTROL AGENTS
• CHAPTER 9: REPRODUCTIVE AND DEVELOPMENTAL TOXICOLOGY OF RIOT CONTROL AGENTS
• CHAPTER 10: GENETIC TOXICITY OF RIOT CONTROL AGENTS
• CHAPTER 11: HUMAN EXPOSURES TO RIOT CONTROL AGENTS
• CHAPTER 12: FORENSIC ASPECTS OF RIOT CONTROL AGENTS
• CHAPTER 13: AN APPROACH FOR ASSESSING AND CHARACTERIZING RISK FROM THE USE OF RIOT CONTROL AGENTS
• CHAPTER 14: OCCUPATIONAL EXPOSURES TO RIOT CONTROL AGENTS
• CHAPTER 15: RISK MANAGEMENT AND PUBLIC HEALTH CONSIDERATIONS OF RIOT CONTROL AGENTS
• CHAPTER 16: ENVIRONMENTAL ISSUES INVOLVING RIOT CONTROL AGENTS
• CHAPTER 17: GENOMICS, PROTEOMICS, AND COMPUTATIONAL TOXICOLOGY AS FUTURE TOOLS IN ASSESSING HEALTH HAZARDS OF RIOT CONTROL AGENTS
• CHAPTER 18: ISSUES/CONCERNS, NEEDS, EMERGING CONCEPTS/TRENDS, AND ADVANCES IN RIOT CONTROL AGENTS
• APPENDIX A: DEFINITIONS AND TERMINOLOGY
• APPENDIX B: DECONTAMINATION AND MEDICAL MANAGEMENT AFTER EXPOSURES TO RIOT CONTROL AGENTS
• APPENDIX C: TABLE OF RIOT CONTROL AGENT FORMULATIONS