CS gas exposure in a crowded night club: the consequences for an accident and emergency department

Noxious effects of riot control agents on the ocular surface: Pathogenic mechanisms and management

Riot Control Agents (RCAs) are chemical compounds used by law enforcement agencies to quell violent demonstrations as an alternative to lethal force and as part of police/military training. They are also known as tear gases because of the hallmark ocular irritation and lacrimation they cause. The most common RCAs include oleoresin capsicum (contained in Mace and pepper spray), chlorobenzylidene malononitrile, dibenzoxazepine, and chloroacetophenone (previously the main content of Mace); some of which have been in use for decades. Their immediate incapacitating effects are mediated through polymodal afferent fibers innervating the corneal surface, inducing the release of peptides that cause neurogenic inflammation. Although previously thought to have only transient effects on exposed patients more severe complications such as corneal stromal opacities, corneal neovascularization, neurotrophic keratopathy, conjunctival necrosis, and pseudopterygium can occur. Concerningly, the lack of research and specific therapies restrict the current management to decontamination and symptom-tailored support. This manuscript will provide an overview of the toxic mechanisms of RCAs, their clinical manifestations, and current therapy after exposure to tear gases.

Reevaluating tear gas toxicity and safety

Tear gases, or chemical demonstration control agents (DCA), were originally created as weapons that could severely disable or kill enemy troops. Though banned in war, these chemicals are still used in domestic policing. Here we review the available scientific literature on tear gas, summarizing findings from animal and environmental studies as well describing data from new human studies. We find a lack of scientific evidence supporting the safety of tear gas, especially regarding its long-term impacts on human health and the environment. Many of the available studies were published decades ago, and do not parse data by variables such as chemical type and exposure time, nor do they account for the diversity of individuals who are exposed to tear gas in real-life situations. Due to the dearth of scientific research and the misinterpretation of some of the available studies, we conclude that a serious reevaluation of chemical DCA safety and more comprehensive exposure follow-up studies are necessary.

Health issues and healthcare utilization among adults who reported exposure to tear gas during 2020 Portland (OR) protests: a cross-sectional survey

Background

Repeated use of chemical irritants for crowd-control by local and federal law enforcement during sustained racial justice protests in the U.S. has raised concerns about potential adverse health effects. The objective of this study was to describe the health consequences of exposure to tear gas agents and associated healthcare utilization among adults reporting recent exposure to tear gas.

Methods

A cross-sectional, self-administered web-based survey of a convenience sample of 2257 adults reporting recent exposure to tear gas in Portland, Oregon (U.S.), administered between July 30, 2020-August 20, 2020. Descriptive analyses were conducted on socioeconomic characteristics, reported health issues, utilization of healthcare services, and frequency of reported exposure to tear gas. Associations between reported mental health issues, healthcare utilization and race and/or ethnic categories were assessed using a chi-square test. For tests of association, racial and/or ethnic categories were divided into White/Non-Hispanic only and all other racial/ethnic categories due to a small number of Black, American Indian or Alaska Native, Asian/Pacific Islander, Hispanic participants and participants with multiple race and/or ethnic background. Effect sizes for the differences were expressed as Cramer’s V, a metric that measures associations between nominal responses. The Cochran-Armitage trend test was used to assess the relationship between health issues and the number of reported days of exposure to tear gas (i.e., a proxy dose of exposure) grouped into 1 day, 2–4 days, and ≥ 5 days. Missing data (item non-response) were omitted from the analysis.

Results

Almost all respondents (2116; 93.8%) reported physical (2114; 93.7%) or psychological (1635; 72.4%) health issues experienced immediately after (2105; 93.3%) or days following (1944; 86.1%) the exposure. A slightly higher proportion experienced delayed head or gastrointestinal tract issues compared with immediate complaints. The majority (1233; 54.6%) reported receiving or planning to seek medical or mental care. We observed a positive exposure-response trend for all except mouth-related delayed issues (p < 0.01).

Conclusion

Persons who reported exposer to tear gas agents also reported physical and psychological health issues over a multiple-day period. Health issues reported increased with the frequency of reported exposure, indicating a potential dose-response; these health effects often led to healthcare utilization. This study provides evidence of potential unexpected harms of tear gas in civilians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10859-w.

Health impacts of chemical irritants used for crowd control: a systematic review of the injuries and deaths caused by tear gas and pepper spray

Background

Chemical irritants used in crowd control, such as tear gases and pepper sprays, are generally considered to be safe and to cause only transient pain and lacrimation. However, there are numerous reports that use and misuse of these chemicals may cause serious injuries. We aimed to review documented injuries from chemical irritants to better understand the morbidity and mortality associated with these weapons.

Methods

We conducted a systematic review using PRISMA guidelines to identify injuries, permanent disabilities, and deaths from chemical irritants worldwide between January 1, 1990 and March 15, 2015. We reviewed injuries to different body systems, injury severity, and potential risk factors for injury severity. We also assessed region, context and quality of each included article.

Results

We identified 31 studies from 11 countries. These reported on 5131 people who suffered injuries, two of whom died and 58 of whom suffered permanent disabilities. Out of 9261 total injuries, 8.7% were severe and required professional medical management, while 17% were moderate and 74.3% were minor. Severe injuries occurred to all body systems, with the majority of injuries impacting the skin and eyes. Projectile munition trauma caused 231 projectile injuries, with 63 (27%) severe injuries, including major head injury and vision loss. Potentiating factors for more severe injury included environmental conditions, prolonged exposure time, and higher quantities of chemical agent in enclosed spaces.

Conclusions

Although chemical weapons may have a limited role in crowd control, our findings demonstrate that they have significant potential for misuse, leading to unnecessary morbidity and mortality. A nuanced understanding of the health impacts of chemical weapons and mitigating factors is imperative to avoiding indiscriminate use of chemical weapons and associated health consequences.

Tear gas: an epidemiological and mechanistic reassessment

Deployments of tear gas and pepper spray have rapidly increased worldwide. Large amounts of tear gas have been used in densely populated cities, including Cairo, Istanbul, Rio de Janeiro, Manama (Bahrain), and Hong Kong. In the United States, tear gas was used extensively during recent riots in Ferguson, Missouri. Whereas tear gas deployment systems have rapidly improved-with aerial drone systems tested and requested by law enforcement-epidemiological and mechanistic research have lagged behind and have received little attention. Case studies and recent epidemiological studies revealed that tear gas agents can cause lung, cutaneous, and ocular injuries, with individuals affected by chronic morbidities at high risk for complications. Mechanistic studies identified the ion channels TRPV1 and TRPA1 as targets of capsaicin in pepper spray, and of the tear gas agents chloroacetophenone, CS, and CR. TRPV1 and TRPA1 localize to pain-sensing peripheral sensory neurons and have been linked to acute and chronic pain, cough, asthma, lung injury, dermatitis, itch, and neurodegeneration. In animal models, transient receptor potential inhibitors show promising effects as potential countermeasures against tear gas injuries. On the basis of the available data, a reassessment of the health risks of tear gas exposures in the civilian population is advised, and development of new countermeasures is proposed.

Exposure to the riot control agent CS and potential health effects: a systematic review of the evidence

o-Chlorobenzylidene malononitrile (CS) is one of the most extensively used riot control agents. Our aim was to conduct a systematic review of the potential health effects related to CS exposure. We searched for papers in English between 1991 and 2014. Thirty five (35) studies (25 case reports, seven descriptive studies and three analytical studies) were included in the review. In the twenty five case reports/series 90 cases of exposure to CS and their clinical effects are presented. Their mean age was 25.7 years and 62.0% were males. In addition, 61% of the cases described dermal, 40% respiratory, 57% ocular clinical effects. Life threatening situations as well as long-term health effects were found and were related with exposure to confined/enclosed space. Descriptive and analytical studies have shown attack rates ranging from 12% to 40%. Subjects who were sprayed by the police more often needed special treatment and reported adverse health effects. Apart from transient clinical effects, CS could have lasting and serious effects on human health. Better surveillance of the subjects exposed to CS and completion of cohort studies among exposed populations will illuminate the spectrum of the health effects of exposure to CS.

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

INTRODUCTION

2-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.

METHODS

OVID 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.

RESULTS

CN, 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.

CONCLUSIONS

CN, 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.

Investigation of accidental secondary exposure to CS agent

We report on an unusual exposure to o-chlorobenzylidene malononitrile (CS agent) following its use to detect unauthorized stowaways aboard a vehicle, and the subsequent handling of the cargo delivered to retail stores across Scotland. Twenty-one staff in 16 retail stores across Scotland experienced symptoms including itching and running eyes, rhinorhoea, a burning sensation on the face and hands, and a burning throat, following the furniture deliveries. A survey was conducted to assess the extent of exposure to the contaminated furniture and the scale of illness associated with exposure. Experiencing symptoms was significantly associated with having contact with the furniture or packaging (chi(2) = 10.5, p < 0.001). This incident demonstrates the risk of inadvertent secondary exposure and subsequent acute symptoms from contact with residual CS agent when sprayed in the confined spaces of haulage vehicles.

Medical Management of the Traumatic Consequences of Civil Unrest Incidents

In the context of this review, civil unrest is defined as disharmony, expressive dissatisfaction and/or disagreement between members of a community, which leads to a situation of competitive aggression that may find expression as disruption of organisation, conflicts, damage to property and injuries. Such a breakdown of harmonious relationships, which may result in property damage and human injuries that may be threatening to life, varies in magnitude from participation of a very few individuals up to the involvement of large crowds of people, which may evolve into a full-scale riot. It is the latter situation often involving demonstrators, opposing groups and law enforcement personnel that can result in multiple casualties and present a very significant challenge to the resources of local healthcare institutions. The causation of civil unrest incidents is multifactorial and has generic, specific and potentiating elements. With the current national and international societal, political and discriminatory problems, it is likely that civil unrest incidents on both small and large scales will continue to occur at a high and possibly increasing rate on a worldwide basis, and for these not infrequent incidents, the medical community should be in a state of informed preparation. The circumstances of civil unrest incidents are very variable with respect to causation, overall magnitude, frequency, timing, geographical location, numbers of persons involved, demographics of participants, influence of extremists, confrontation with opposing groups and control measures used by law enforcement agencies. Methods used by police and security forces for the control of civil unrest incidents, if advanced negotiations with organisers and verbal warnings have failed, fall basically into two categories: physical and chemical measures. Physical methods include restraint holds, truncheons, batons, mounted horses, projectiles (such as bean bags, plastic and rubber bullets), water cannons, tasers and (rarely) live ammunition. All of these physical measures are associated with pain and immobilisation, and there is a high potential for soft tissue and bone injuries. Some of the more severe physical methods, including plastic and rubber bullets, may cause lethal injuries. The basis for using chemicals in civil unrest incidents is that they cause distraction, transient harassment and incapacitation, temporary impairment of the conduct of coordinated tasks and cause a desire to vacate the area of unrest. Although screening smokes and malodors have sometimes been employed, the major group of chemicals used are peripheral chemosensory irritants (PCSIs), which reversibly interact with sensory nerve receptors in exposed skin and mucosal surfaces, resulting in the production of local uncomfortable sensations and associated reflexes. Major effects are on the eye, respiratory tract and (to a lesser degree) skin. Thus, the induced transient pain and discomfort in the eye, respiratory tract and skin, together with associated lacrimation, blepharospasm, rhinorrhoea, sialorrhoea, cough and breathing difficulties, produce temporary incapacitation and interference with the conduct of coordinated tasks, and form the basis for harassment of malefactors. Currently used peripheral chemosensory irritants are 1-chloroacetophenone, 2-chlorobenzylidene malononitrile, dibenz(b.f)-1,4-oxazepine, oleoresin capsicum and pelargonic acid vanillylamide. Depending on operational circumstances, irritants may be dispersed as a smoke, powder cloud, aerosol, vapour, or in solution; the mode of generation and dispersion of irritant can influence hazard. Brief acute exposure to chemosensory irritants produces effects that generally resolve within an hour, leaving no long-term sequelae. However, sustained exposure to high concentrations may produce tissue injury, notably to the eye, respiratory tract and skin. With solutions of sensory irritants, other formulation constituents may enhance PCSI toxicity or introduce additional local and/or systemic toxicity. By the very circumstances of civil unrest incidents, injuries are inevitable, particularly when emotions are heightened and police and security forces have to resort to various chemical and/or physical means of control. Trauma may include slight to severe physical and/or chemical injuries, psychological problems and occasional deaths. Hospitals should be prepared for a wide range of casualties, and the fact that those seeking help will constitute a heterogeneous group, including wide age range, male, female, and individuals with pre-existing ill health. A major civil unrest incident necessitates that the local receiving hospital should be prepared and equipped for decontamination and triage processes. It is necessary to reassure patients who have been exposed to sensory irritants that the signs and symptoms are rapidly reversible, and do not result in long-term sequelae. With respect to chemical exposures, detailed evaluation should be given to possible ocular, cutaneous, respiratory and gastrointestinal effects. Also, exposure to chemosensory irritants results in transient increases in blood pressure, bradycardia and increased intraocular pressure. This indicates that those with cardiovascular diseases and glaucoma may be at increased risk for the development of complications. This article details the pharmacological, toxicological and clinical effects of chemicals used in civil disturbance control and discusses the management of contaminated individuals. Additionally, the potential for adverse effects from delivery systems and other physical restraint procedures is summarised. Due to the emergency and specialised circumstances and conditions of a civil unrest incident, there is a clear need for advanced planning by healthcare institutions in the event that such an incident occurs in their catchment area. This should include ensuring a good information base, preparations for medical and support staff readiness, and availability of required equipment and medications. Ideally, planning, administration and coordination should be undertaken at both local (regional) and central (governmental) centres. Regional centres should have responsibilities for education, training, ensuring facilities and staffing are appropriate, and that adequate equipment and medicines are available. There should be cooperative interactions and communications with local police and other emergency services. Centrally directed functions should include ensuring adequacy of the information base, coordinating activities and agreeing approaches between the regional centres, and periodic audits of regional centres with respect to the staffing, facility, equipment and training needs. Also, there is a need for most countries to introduce detailed guidelines and formal (regulatory) schemes for the assessment of the safety-in-use of chemicals and the delivery systems that are to be used against heterogeneous human populations for the control of civil unrest incidents. Such regulatory approval schemes should also cover advisory functions for safe use and any required restrictions.

Medical hazards of the tear gas CS. A case of persistent, multisystem, hypersensitivity reaction and review of the literature

A 30-year-old incarcerated man was sprayed with the "tear gas" ortho-chlorobenzylidene malononitrile (CS). He was hospitalized 8 days later with erythroderma, wheezing, pneumonitis with hypoxemia, hepatitis with jaundice, and hypereosinophilia. During the subsequent months he continued to suffer from generalized dermatitis, recurrent cough and wheezing consistent with reactive airways dysfunction syndrome, and eosinophilia. These abnormalities responded to brief courses of systemic corticosteroid but recurred off therapy. The dermatitis resolved gradually over 6-7 months, but the patient still had asthma-like symptoms a year following exposure. Patch testing confirmed sensitization to CS. The mechanism of the patient's prolonged reaction is unknown but may involve cell-mediated hypersensitivity, perhaps to adducts of CS (or a metabolite) and tissue proteins. This is the first documented case in which CS apparently caused a severe, multisystem illness by hypersensitivity rather than direct tissue toxicity. Both the ethics and safety of CS use remain controversial, in part because of the difficulty documenting sporadic injuries received in the field, and also because the charged circumstances surrounding CS use may lead to both underreporting and exaggerated claims of medical harm. The medical literature on CS focuses mainly on its immediate irritant effects and on transient dermal and ocular injuries, with only 2 prior case reports of acute lung injury related to CS exposure. Given the paucity of documented lasting effects despite its widespread use for more than 3 decades, CS appears to be safe when deployed (outdoors) in a controlled manner, but it can cause important injuries if misused or if applied to a sensitized individual.

CS exposure--clinical effects and management

The number of people exposed to CS spray presenting to accident and emergency departments is on the increase. Its effects, though usually minor and short lived, involve several systems and can occasionally be life threatening. It is therefore important that staff are able to manage these patients and know when and how to protect themselves and others from further contamination.