Acute mass burns caused by o-chlorobenzylidene malononitrile (CS) tear gas

Reduction of Oxygen Production by Algal Cells in the Presence of O-Chlorobenzylidene Malononitrile

Chemical compounds, such as the CS gas employed in military operations, have a number of characteristics that impact the ecosystem by upsetting its natural balance. In this work, the toxicity limit and microorganism's reaction to the oxidative stress induced by O-chlorobenzylidenemalonitrile, a chemical found in CS gas, were assessed in relation to the green algae Chlorella pyrenoidosa. A number of parameters, including the cell growth curve, the percent inhibition in yield, the dry cell weight, the percentage viability and productivity of algal biomass flocculation activity, and the change in oxygen production, were analyzed in order to comprehend the toxicological mechanisms of O-chlorobenzylidenemalonitrile on algal culture. Using fluorescence and Fourier transform infrared spectroscopy (FTIR), the content of chlorophyll pigments was determined. The values obtained for pH during the adaptation period of the C. pyrenoidosa culture were between 6.0 and 6.8, O2 had values between 6.5 and 7.0 mg/L, and the conductivity was 165-210 µS/cm. For the 20 µg/mL O-chlorobenzylidenemalonitrile concentration, the cell viability percentage was over 97.4%, and for the 150 µg/mL O-chlorobenzylidenemalonitrile concentration was 74%. The ECb50 value for C. pyrenoidosa was determined from the slope of the calibration curve; it was estimated by extrapolation to the value of 298.24 µg/mL. With the help of this study, basic information on the toxicity of O-chlorobenzylidenemalonitrile to aquatic creatures will be available, which will serve as a foundation for evaluating the possible effects on aquatic ecosystems. The management of the decontamination of the impacted areas could take the results into consideration.

Synthesis, Purity Check, Hydrolysis and Removal of o-Chlorobenzyliden Malononitrile (CBM) by Biological Selective Media

The removal yield of organic substances present in water depends on the environmental conditions, on the chemical composition of the water and on the chemical substance dissolved in the water, which constitutes the substrate of the metabolic activities of the microalgae that use these substances in the biochemical reactions of cellular enzyme complexes. o-Chlorobenzylidene malononitrile (CS, to use its military designation) was synthesized in-house, for research purposes, by a condensing reaction between o-chlorobenzaldehide and malononitrilein the presence of diethylamine. The detection, identification and confirmation of o-chlorobenzylidenemalononitrile (coded CBM in this experimental study) was performed using gas chromatography-mass spectrometry (GC-MS) and the purity of CBM was 99%. The biodegradation capacity in the samples that contained the biological suspension, after 24 h and 96 h of incubation, was determined via GC-MS analysis, and no evidence of the presence of CBM or some metabolites of CBM was detected. In the parallel samples, a hydrolysis process of CBM at room temperature, without biological treatment, revealed two main metabolites, malononitrile and o-chlorobenzaldehyde, respectively. This study is focused on evaluating the biodegradation capacity of o-chlorobenzylidene malononitrile in the presence of a biological material, culture of Chlorella sp., in comparison with a classical hydrolysis process. The tests performed indicate that the suspension of Chlorella sp. consumed the entire amount of CBM and metabolites from the analyzed samples. The tests prove that the biological material can be used to decontaminate the affected areas.

The language of less-lethal weapons

It has been over 1 year since we observed the policing of the George Floyd protests in the United States [R. R. Hardeman, E. M. Medina, R. W. Boyd, N. Engl. J. Med. 383, 197-199 (2020)]. Multiple injury reports emerged in medical journals, and the scientific community called for law enforcement to discontinue the use of less-lethal weapons [E. A. Kaske et al., N. Engl. J. Med. 384, 774-775 (2021) and K. A. Olson et al., N. Engl. J. Med. 383, 1081-1083 (2020)]. Despite progress in research, policy change has not followed a similar pace. Although the reasoning for this discrepancy is multifactorial, failure to use appropriate language may be one contributing factor to the challenges faced in updating policies and practices. Here, we detail how language has the potential to influence thinking and decision-making, we discuss how the language of less-lethal weapons minimizes harm, and we provide a framework for naming conventions that acknowledges harm.

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.

Riot-related injuries managed at a hospital in Beirut, Lebanon

BACKGROUND

Between October 2019 and February 2020, massive crowds protested in Lebanon against economic collapse. Various less than lethal weapons including riot control agents and rubber bullets were used by law enforcement, which led to several traumatic and chemical injuries among victims. This study describes the clinical presentation, management, outcome, and healthcare costs of injuries.

METHODS

A retrospective review of the hospital records of all the casualties presenting to the Emergency Department of the American University of Beirut Medical Center between October 17th, 2019, and February 29th, 2020, was conducted.

RESULTS

A total of 313 casualties were evaluated in the ED, with a mean age of 30.2 +/- 9.6 years and a predominance of males (91.1%). Most were protestors (71.9%) and arrived through EMS (43.5%) at an influx rate of one patient presenting every 2.7-8 min. Most patients (91.1%) presented with an Emergency Severity Index of 3. Most patients (77.6%) required imaging with 10% having major findings including fractures and hemorrhages. Stones, rocks, and tear gas canisters (30.7%) were the most common mechanism of injury. Musculoskeletal injuries were most common (62.6%), followed by lacerations (44.7%). The majority (93.3%) were treated and discharged home and 3.2% required hospital admission, with 2.6% requiring surgery.

CONCLUSION

Less-than-lethal weapons can cause severe injuries and permanent morbidity. The use of riot control agents needs to be better controlled, and users need to be well trained in order to avoid misuse and to lessen the morbidity, mortality, and financial burden.

Direct head injury caused by a tear gas cartridge. Questions on safety: A case report from Iraq and review of the literature

INTRODUCTION AND BACKGROUND

Primary injuries from tear gas weapons include injuries to the visual and respiratory systems and skin. However, few studies have reported direct mechanical brain injuries from tear gas weapons.

CASE REPORT

A 27-year-old male presented to the emergency department of a neurosurgery teaching hospital in Baghdad, Iraq, with a penetrating head injury of unknown source.

DISCUSSION

Tear gas weapons are considered safe, but tear gas exposure causes severe complications. Traumatic brain injuries as a direct effect of tear gas bombs are rarely reported in the literature. Tear gas cartridge injuries should be managed in the same manner as any penetrating brain injury, with appropriate neuromonitoring. This monitoring is crucial for the detection and prevention of secondary brain insults.

CONCLUSION

Emergency medicine specialists and neurosurgeons should be aware that tear gas weapons are not always safe, and they should anticipate chemical, thermal and mechanical side effects of tear gas weapons. The literature and our results suggest that these weapons should not be considered civil and harmless.

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.

Medical care in civil disorder

Civil disorder may be defined in widely differing terms, depending largely on the political and legal system prevailing in a given country. The way in which the authorities manage disorder has important implications for both internal stability and the country’s international image, and to a great extent the number of injuries will also depend on the effectiveness of this management.

For the police, ambulance service and hospitals, civil disorder will often necessitate the invocation of their respective major incident plans. Since the response requirements may be very different from other disasters, such plans need to address civil disorder specifically.

This paper reviews the various wounding agents that may be used by participants in civil disorder, and by security forces in their response. The issues of personal safety for emergency service staff are reviewed, and the organizational aspects of medical care emphasized.

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.

The pathology of lethal exposure to the Riot Control Agents: towards a forensics-based methodology for determining misuse

The aim of this is to review deaths associated with the use of Riot Control Agents (RCAs) and to assess how the presenting pathologies is such cases may better inform cause of death conclusions upon autopsy. We also sought to present which additional steps should be added to the Minnesota protocol and the European harmonization of medico-legal autopsy rules in suspected cases of deaths associated with the use of RCAs. We included 10 lethal cases in our study. In three cases, RCAs were found to be the sole cause of death, in three cases RCAs were ruled a secondary cause of death due asphyxia or asthma subsequent to exposure to RCAs and in four cases RCAs were contributory factors to death. In three cases the responsible agents were identified as Chloroacetophenone (CN), Chlorobenzylidene malononitrile (CS) and Oleoresin capsicum (OC) and in the remaining 7 cases, the agent was OC alone. As there are no specific findings in suspected cases of death associated with RCA use, establishing cause of death and whether RCAs are the sole cause or only a contributory factor will be based on the elimination of other possible causes of death. For this reason, a specifically structured autopsy is essential. This specifically structured autopsy should contain basic principles of the Minnesota Protocol and the European harmonization of medico-legal autopsy rules with the following additional steps taken: examination of clothing, eyes, and skin; examination of pharyngeal, tracheobronchial, and eusophegeal mucosas; and a thorough recording of the steps taken by the party conducting the arrest, including other possible causes of in-custody death, as well as a detailed medical history of the deceased.

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.

A Study for Health Hazard Evaluation of Methylene Chloride Evaporated from the Tear Gas Mixture

This study explored the health hazard of those exposed to methylene chloride by assessing its atmospheric concentration when a tear gas mixture was aerially dispersed. The concentration of methylene chloride ranged from 311.1-980.3 ppm (geometric mean, 555.8 ppm), 30 seconds after the dispersion started. However, the concentration fell rapidly to below 10 ppm after dispersion was completed. The concentration during the dispersion did not surpass the National Institute for Occupational Safety and Health 'immediately dangerous to life or health' value of 2,300 ppm, but did exceed the American Conference of Governmental Industrial Hygienists excursion limit of 250 ppm. Since methylene chloride is highly volatile (vapor pressure, 349 mmHg at 20℃), the postdispersion atmospheric concentration can rise instantaneously. Moreover, the o-chlorobenzylidenemalononitrile formulation of tear gas (CS gas) is an acute upper respiratory tract irritant. Therefore, tear gas mixtures should be handled with delicate care.

Mass chemical burn casualty: Emergency management of 118 patients with alkali burn during a Matsa typhoon attack in Shanghai, China in 2005

BACKGROUND

This article reports a chemical burn incident that occurred on August 7th, 2005, when a Matsa typhoon hit Shanghai, China. This is the largest chemical burn incident reported in the literature for 20 years in China, involving 118 alkali burn patients who were rescued by the Burn Department of Shanghai Changhai Hospital independently.

METHODS

The scene of the incident was investigated, and the clinical, emergency and hospitalized data of the patients were summarized.

RESULTS

The main injurious chemical was a water solution of sodium hydroxide and ammonium chloride. The 118 victims were mostly young men with 5%TBSA deep thickness burn of both lower extremities, including 31 patients who had additional light coughing. Of 58 patients who were finally hospitalized, 42 patients received surgical treatment. Most of these patients recovered within 1 month. There were no deaths.

DISCUSSION

Retrospective analysis of the therapeutic data of the incident demonstrates that pre-designed disaster planning for emergency management of mass burn patients, an effective command group, accurate assessment of pathological conditions, and correct allocation of different casualties are key elements in successful management in a mass casualty even involving burn patients. In addition, it is essential for specialized personnel to take part in emergency treatment of chemical burns.

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.

Respiratory agents: irritant gases, riot control agents, incapacitants, and caustics

There are many chemical respiratory agents suitable for use by terrorists. They are the oldest chemical agents used and have caused the most casualties throughout the 20th century. Many are available in large quantities for industrial use and are susceptible to potential sabotage. This paper will concentrate on respiratory agents that are readily available and have the potential to cause a large number of casualties and panic. These agents have a lower rate of lethality when compared to other chemical agents but could produce many casualties that may overwhelm the emergency medical system.

Prevention of CS “tear gas” eye and skin effects and active decontamination with Diphoterine: Preliminary studies in 5 French Gendarmes

Ortho-chlorobenzylidene malononitrile (CS) "tear gas" is a lacrimating riot control agent causing eye irritation, excessive lacrimation, and blepharospasm. Diphoterine has been efficacious for decontamination of a wide variety of eye and skin chemical splashes and was tested in CS exposure. Five French Gendarmes either entered a standard training CS exposure chamber, developed eye or skin signs and symptoms, and were post-exposure decontaminated with Diphoterine or used Diphoterine as pre-CS exposure prophylaxis in the eyes and on the face before entering the chamber. Gendarmes who entered the CS chamber without prior application of Diphoterine developed expected effects of excessive lacrimation, eye irritation, and blepharospasm. After post-exposure Diphoterine decontamination, in four Gendarmes these effects rapidly resolved and they were fully operational. When Diphoterine was applied to the eyes and face before entering the CS chamber, the expected effects did not occur and the single Gendarme remained fully operational on exiting the chamber. These results suggest that Diphoterine can prevent or rapidly ameliorate the ocular and dermal effects of CS and allow law enforcement personnel to remain fully operational or rapidly regain operational status after decontamination.

Cutaneous burns from CS incapacitant spray

A case of a superficial burn following exposure to CS incapacitant spray is reported. This is followed by a summary of the properties and effects of CS and the other agents which occur in the incapacitant spray. CS is relatively safe, but it does have unwanted effects, especially on skin exposure. Possible contributing factors to the production of a skin burn are discussed.

Pediatric burn patients from Vietnamese camps in Hong Kong from 1989 to 1997

Over the 9 years from 1989 to 1997, many children who suffered from scald burns in the Vietnamese camps in the New Territories of Hong Kong were treated. The profile of these children was examined and analyzed.

Victims of the Palestinian uprising (Intifada): a retrospective review of 220 cases

The purpose of this study was to review the cases of the victims of the Palestinian uprising (Intifada) and to describe the clinical presentations, the types of weapons used, and the different sites of injuries. This is a retrospective chart review study of the patients who were injured during the Palestinian uprising in the period April 1993-April 1994 and treated in the emergency department of the Barzilai Medical Center, Ashkelon, Israel. The Barzilai Medical Center is a regional level II trauma referral general hospital. Two hundred and twenty patients were injured during the Palestinian uprising and referred to our emergency department. Forty-one patients were citizens of the Gaza area, 26 patients were Israeli civilians, and 153 were Israeli soldiers. There were 55 patients (25%) injured by firearms, 10 patients (4.5%) by explosives, and 120 (54.5%) by striking stones. Seventy-three patients (33.2%) were hospitalized, and 22 patients needed surgery. The most commonly injured part of the body was the lower limb among the Gaza citizens and the head and neck among the Israeli soldiers and civilians. Striking stones was the most common means of injury used by the Palestinians, and stab wounds by knives and other sharp objects were the most common injuries among Israeli civilians. None of the patients suffered direct blast injuries. The Palestinian uprising resulted in many victims and disabled people in both nations. Terrorism did not cease after the peace treaty. It changed its face and moved from Gaza to the center of Israel. Suicidal terrorist bombing in public spaces and public buses carries more danger and more victims with much more severe injuries. We hope that the future will be brighter, and both nations will eventually be able to live in peace.