The Future of Tear Gas


By MGySgt Gary Beals

Most of the world separates the use of the riot control agent tear gas from banned chemical warfare agents. The United States uses this separation to justify tear gas employment by the U.S. Departments of Defense and State, and domestic law enforcement. U.S. policy on tear gas is rooted in tradition rather than current data and tear gas use of any kind today is at least ineffective, and at its worst counterproductive. Tear gas use of any kind by the United States threatens to normalize the use of gas as a weapon globally; but domestic law enforcements’ indiscriminate use of tear gas increases the possibility of transmission and more severe effects from COVID-19. With numerous alternatives for crowd control and dispersal available, it is time the United States change its policy on tear gas and take the lead internationally in adapting to changing health and security dynamics.

The chemical name for tear gas is 2-Chlorobenzylidenemalononitrile, and it is not truly a gas. The moniker tear gas refers to one of the symptoms closely associated to exposure. Tear gas is actually composed of fine crystalline particles of 2-Chlorobenzylidenemalononitrile that are aerosolized. The wide-spread use of toxic gasses became prevalent during and directly after World War I. Gas weapons proved tremendously effective at causing casualties and striking fear into the hearts of combatants and non-combatants alike. During World War I, both the Allied and Central powers weaponized tear gas initially before gradually switching to deadlier chlorine and mustard gasses. By 1915, chemical companies that previously manufactured tear gas for the military were seeking new clients. At this time, civil unrest dominated post-war America. High unemployment levels inflamed existing social tensions and led to riots across the country, partially spurred-on by the number of women and minorities occupying jobs usually forbidden to them. Law enforcement agencies sought new ways to control and disperse crowds, and the chemical companies were ready to provide a new tool for the job.


U.S. policy on tear gas has evolved over time. After World War I, the text of the Geneva protocol stated that “the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices, has been justly condemned by the general opinion of the civilized world.” Though the United States agreed with the overall purpose of the Geneva Protocol, the United States was one of the few major powers that did not originally ratify it, seeing no reason to agree not to use a weapon on other countries who might use them first. By 1919, America began to use tear gas for domestic law enforcement. Tear gas use in controlling domestic issues was not viewed as warfare, and therefore was not in violation of Geneva. In fact, U.S. policy retained the right to employ all types of chemicals as weapons for retaliation in kind until the Chemical Weapons Convention went into effect in 1997.

In Vietnam, the United States fully embraced the use of non-lethal agents in order to accomplish certain missions and reduce collateral damage. The United States used tear gas extensively during the period of the Vietnam War both abroad and domestically. As the Cold War raged on, communist countries, such as Hungary, expressed their open disapproval of the U.S. predilection to employ gas weapons in war, which they interpreted as inconsistent with the Geneva Protocol. The United States found no reason to involve itself in further negotiations of any treaty when the Soviet Union had potential leverage.

The Cold War was arguably a leading factor slowing the forward movement of the new Chemical Weapons Convention which began in 1980. The Chemical Weapons Convention entered into force in 1997 and was far more specific than the Geneva Protocol of 1925. The United States withdrew its reservation to use chemical weapons in retaliation for enemy use but stood firm on the need to use riot control agents, such as tear gas, in certain situations, and only with Presidential approval. The Chemical Weapons Convention plainly states that “Each State Party undertakes not to use riot control agents as a method of warfare.” Although many countries use tear gas for domestic law enforcement, no other nation that is a signatory to the Chemicals Weapons Convention reserves the right to use tear gas in war except for the United States. The unique American relationship with tear gas, makes the United States a likely advocate for significant change in global policy. But why would the United States change its stance now? Continued tear gas use is ineffective, counterproductive, and dangerous when paired with COVID-19.

Istanbul, Turkey – June 11, 2013: Hundreds of protesters clashed with police in Taksim Square. A wave of demonstrations and civil unrest in Turkey began on 28 May 2013, initially to contest the urban development plan for Istanbul’s Taksim Gezi Park. The protests were sparked by outrage at the violent eviction of a sit-in at the park protesting the plan.

Ineffective and Counterproductive

The United States military uses a case study of employing tear gas in order to help teach the value of effective communication and the operational risks inherent in tear gas use. The case study centers on the freighter Mayaguez that Cambodian forces seized in 1975. This event took place on the heels of the extensive operational tear gas use in the Vietnam War, and involved a boarding party of U.S. Marines and Cambodian military. The Marines saturated the ship with tear gas in an attempt to off-balance the hijackers and make it easier to take back the vessel. The tactic was so counterproductive that the Marine Corps includes it as a vignette of what not to do in its Leading Marines warfighting publication. The after-action report from the Mayaguez incident notes that tear gas adds friction and complicates operations by reducing visibility and the ability to communicate. The after actions and lessons learned are captured in the Marine Corps Warfighting Publication 6-11, or Leading Marines, and is a mandatory reading for all new enlisted Marines upon graduation from boot camp and all officers while in The Basic School in Quantico, Virginia.

The primary focus of less-than-lethal devices is to disrupt specific hostiles in a mob in order to deescalate the situation. Although tear gas is not a true gas, it does have many of the same characteristics and properties of a gas. Tear gas is heavier than air and travels along the contours of the ground until it eventually settles into a fine powder on whatever surface it contacts. It is impossible to control once released, but more importantly; the fine tear gas particles settle onto surfaces and can persist for days or weeks, depending on rainfall, and become aerosolized again if that surface is disturbed. Specific targeting is not possible with tear gas and escalation of the incident is more likely than de-escalation.

Large protests are often held to draw attention to social concerns and in the United States, most protestors’ intentions are peaceful. The center of metropolitan areas often play host to these events because they offer the best opportunity for the widest dissemination of the message. When police use tear gas to disperse these events, it is impossible to avoid exposure to adjacent residences, businesses, and other nonparticipating parties. Businesses are often huddled close together in urban areas, and apartments and condominiums in the inner city often have shared entrances at the street level. Tear gas is already difficult to predict, but the variables in a densely populated urban area are incalculable.

Tear gas use is completely unpredictable; this is also evidenced by cases of determined protesters redirecting tear gas canisters by throwing or kicking them, which drastically alters the intended effects. Trained employers of tear gas are taught to observe wind direction and employ tear gas canisters when the environment favors the intent. However, determined rioters who bring their own personal protective equipment, do not receive the intended effect; instead, the effects are often experienced by peaceful protesters and bystanders. In Dallas, in the summer of 2020, burning canisters were kicked and thrown by protesters, starting fires in the city and changing the intended direction of the gas. There is no way to prevent this from occurring, except to not use the tear gas canisters.

Law enforcement, like the Department of State, employs tear gas to disperse a crowd or move people away from a specific location; but again, tear gas does not always produce the desired effect. People react differently in crowds than they do as individuals. The path of gas, once released, is subject to meteorological interference as well as human interference. Although training is conducted with law enforcement at all levels, the experiences of the U.S. military demonstrates that communication breaks down at all levels when tear gas is used. Communication is particularly important in the domestic United States where the right to assemble is constitutionally protected. Law enforcement training should stress the need to exhaust all potential for communication before, during, and after employing compliance measures in a persistent effort to deescalate a dangerous situation. Once tear gas is employed, it all but destroys any opportunity for communication between law enforcement and the population.

A cause-and-effect relationship potentially exist between the use of tear gas, and the escalation not de-escalation of rioters. Mobs are not made up of all bad people. For years scientists have studied crowd mentality, and consistently determined that normal everyday people can be whipped into actions they would never undertake otherwise by an emotional crowd. These same people then return to their previous unemotional state after the time with the crowd ends and there is no longer an influential and aggressive leader. We can learn a lot by looking at international events and analyzing tear gas’s effectiveness there. Hong Kong security elements saturated the streets with tear gas. According to journalists on scene, the extensive use of gas seemed to galvanize the people, who all had a new suffering in common. Citizens who had not taken an active position, now found themselves under the same treatment as those actively protesting. The tear gas is potentially turning otherwise peaceful people into part of the mob by indiscriminately targeting them. The riots in Hong Kong are by any standard, very large; tear gas was ineffective at dispersing them and have by some accounts, made them worse.

Communication is also crucial between law enforcement and large groups of people as well as within the law enforcement itself. Communication becomes potentially irreconcilable after tear gas is employed. The Departments of Defense and State have problems communicating while wearing masks and employing tear gas while the law enforcement community is no different. Voice projection attachments are available for almost every model of protective mask, but there are limits to their use. Communication between law enforcement personnel while wearing masks is complicated, and this complication places unnecessary stress on the officers. Officers under stress are more likely to have impaired judgment which can lead to missteps in normally routine procedures.

More important than the communication from officer to officer, is the communication from officer to protesters. Tear gas makes it difficult for the officers to speak to the protesters, and for the protesters to speak to the officers. Tear gas use all but ends the opportunity for peaceful reconciliation or discourse, by eliminating the ability of the two sides to communicate. Instructions from the officers become impossible to hear or understand by the protesters, and the officers can see this as noncompliance. It is not difficult to interpret how a situation like this can quickly escalate, yet tear gas is still employed by U.S. law enforcement.

Seattle, USA – May 1, 2015: Masked protestors and Photographers being pushed back by the Seattle Police late in the day on Denny Way by deployed flash bangs during an intense Anti Capitalist March. The march quickly turned violent on Capitol Hill and several police officers were injured by rocks being thrown by protestors.

New Dangers from COVID-19

The long-term effects of the COVID-19 virus are as yet undetermined, and the symptoms are variable and inconsistent. Changes will have to be made to many areas of everyday life in the United States, many of which are already occurring. The unknown long-term impacts of the COVID-19 pandemic coupled with the known effects of tear gas make continued employment by the United States dangerous and possibly inhumane.

Tear gas exposure has long been associated with an increase in susceptibility to respiratory infections. Controlled tear gas exposure occurs every day at U.S. military basic training locations around the country. New recruits are often young, healthy, and in above- average physical condition. Medical studies from basic training show increases in the occurrence of influenza directly following tear gas exposure. The conclusion is that tear gas exposure makes even healthy people more susceptible to viruses that use the respiratory tract as the primary route of entry. This susceptibility is likely due to the fine particulates that constitute tear gas damaging the airway and the lungs, making it easier for viruses to enter the body. With lungs damaged from tear gas, individuals would be more susceptible to viruses who use the respiratory system as a primary route of entry like COVID-19.

Basic military recruits are issued protective masks and their exposure, though often concentrated, is for a very limited time. The event is also very controlled and supervised in order to observe and identify individuals that have significant adverse reactions to the irritant. The military makes it very clear that individuals who have open sores and existing respiratory issues do not participate in the training event, for fear of further injury. Contact lenses are also prohibited during the training, as the tear gas crystals are known to attach to the lenses and scratch the cornea, potentially causing permanent damage. Pregnant service members, and those who believe they might be pregnant, are also removed from the training event in order to avoid harm to the unborn child. With all of these safety precautions taken by the military, it is a wonder how the law enforcement community can determine when it is safe to employ tear gas in a crowd of unknown and unidentified individuals.

One suspected symptom of COVID-19 is a significant reduction, or complete loss, of the sense of smell. A reduced ability to smell will reduce sensitivity to tear gas and could lead to a much higher exposure before effects are felt. Higher exposure to the particulates inside tear gas have been proven to have negative physiological effects. This is one of the reasons the U.S. military limits and controls the exposure to service members. If an individual’s sensory warning system was already compromised due to COVID-19, then that person would not be fully aware of tear gas, until they had potentially already received a much higher-than-normal dose.

What is known about COVID-19 infections, is that it causes irritations of the lungs and is fatal in some cases. The extent of the lung damage, and the extent to which the patient recovers is unknown at this time. If COVID-19 does cause permanent damage to the lungs, as some studies suggest, then tear gas’s label as a non-lethal substance needs to be reevaluated. The last severe pandemic was in 1918; World War I was underway and chemical warfare had begun in earnest. The first known U.S. cases of the 1918 pandemic occurred on a military base in Kansas. World War I ended in November of 1918, and troops had begun to return home earlier that year. Service members returned to their homes around the world with aggravated lungs from the largest known use of chemical weapons in war. We will never know for sure, but it is not a stretch to postulate that soldiers returning home had compromised respiratory systems and were easy targets for the spread and multiplication of the new virus and the increased severity of its effects. Keeping in mind, in the United States in 1918 tear gas was just beginning to be used by law enforcement. Law enforcement use of tear gas likely helped to create a ripe physiological environment for respiratory virus transmission in America’s population, by damaging the lungs of protesting citizens with early forms of tear gas. Continued tear gas employment is both more dangerous, because it could be fatal to people with compromised respiratory systems, and inhumane, because it makes those exposed more susceptible to infection from COVID-19.

Tear gas use has never produced significant long-term casualties, regardless of the amount used or the population it was used on, but COVID-19 potentially changed the characteristics of the population that data was obtained from. By conservative accounts, the number of Americans that have had COVID-19 exceeds 30 million, with other data making that number twice as high to account for asymptomatic cases. The people who survive the virus could have long term, if not permanent, damage to their respiratory systems. Serious incidents resulting from the combination of COVID-19 and tear gas are likely and could alter the fatality statistics of tear gas use. The United States, and many other nations, hold true to the idea that tear gas is safe and effective to consistently use in domestic situations. When other alternatives did not exist, and before there was a new pandemic to contend with, this statement had higher validity than it does now in the wake of COVID-19. Today there is no benefit to the continued use of tear gas by domestic law enforcement and its continued use adds unnecessary risk to public health.

The Next Step

Almost 25 years have passed since the United States solidified its position regarding chemical weapons and deposited its instrument of ratification to the Chemical Weapons Convention. At that time, the United States and all original signatories entered into an agreement with the long title of “The Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction.” The regular use of tear gas by anyone dulls general sensitivity to the employment of gases and increases the risk of lethal chemical warfare agent use around the world. In using tear gas to repel protesters, the United States is potentially reversing the revulsion for gas use developed after the First World War. Gas use is often seen today as a nuisance, and the never-ending stream of media coverage confirms the inability of tear gas to prevent or end large protests and riots. The process of ridding the world of chemical weapons is an incremental one, and each major step, as suggested by the long title above, requires a strong country to take the lead for the benefit of all. The United States’ next step in its commitment to the spirit of that document is to reevaluate its position on tear gas and to ban its use across all areas of operation.

About the Author

Master Gunnery Sergeant Gary Beals – MGySgt Beals joined the Marine Corps in 1999 as a nuclear, biological, and chemical defense specialist. He has been responsible for the training of U.S. Marines to operate in CBRN environments his entire career. He has also been instrumental in the managing and execution of the Marine Corps’ domestic response mission through the Chemical Biological Incident Response Force (CBIRF) out of Indian Head, MD. MGySgt Beals deployed in support of various missions from humanitarian aid support to Haiti to combat missions with Marine Special Operations Command in Afghanistan. He has a BA in History from American Military University and a MS in Countering Weapons of Mass Destruction from Missouri State University. MGySgt Beals has worked closely throughout his career with both U.S. and foreign federal agencies to increase interoperability between local and federal assets when responding to WMD incidents. In 2018, he became the first U.S. enlisted service member to be selected for the National Defense University’s Countering Weapons of Mass Destruction Graduate Fellowship. He is currently assigned as the CBRN operations coordinator for the First Marine Expeditionary Force out of Camp Pendleton, CA.

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