• Cassandra He

How the Virus Benefitted From Tear Gas Tactics

Banned by the Geneva Accords, tear gas is still used by American police on protestors. How it ravages to body is not fully understood.

Tear gas is a common dispersal tactic used by U.S. police despite its dangers being understudied (PBS).

The words “I can’t breathe!” ring out from among a throng of protesters in a Philadelphia Black Lives Matter protest on June 1, 2020. But this time it’s not a cry of protest — it’s a cry for help as thousands of peaceful protesters face the thick plumes of tear gas.


Unfortunately, the scene witnessed in Philadelphia is a familiar one for Americans. Over the past year, tear gas has been used in over 100 U.S. cities. Protesters all over the country have all faced similar fates as the ones seen in Philadelphia. While some proponents push tear gas as a less dangerous method of suppressing a protest, there are many consequences to using this chemical weapon, especially in the midst of the COVID-19 pandemic.


Tear gas, scientifically referred to as 2-chlorobenzalmalononitrile (CS gas), was first synthesized in 1928 by U.S. scientists Ben Corson and Roger Stoughton for military use in World War I.

The United Nations later banned tear gas from warfare in the Geneva Accords, which prohibited the use of chemical weapons in warfare signed by 38 countries, including the U.S.

Despite this, CS gas continues to be one of the primary riot control agents used by police forces all over the world. In recent years, tear gas usage has seen a surge in many countries, including Turkey, the U.S., Greece, Brazil, Egypt, and Bahrain.

Tear gas, despite its name, is not a gas but a fine powder that is released into the air as a mist. It primarily causes irritation in the tear ducts and respiratory tracts by reacting with water and binding to pain receptors in these areas. Immediate reactions include tearing up, coughing, and even vomiting. While CS gas has been labeled as a nonlethal agent, its effects can be more extreme for the elderly, children, those who are pregnant, and especially those with underlying health conditions. Effects generally wear off 15-30 minutes after exposure.


For the most part, there does not seem to be any long-term effects of CS gas on the general population, though research on this topic is rather limited. Additionally, many of the studies that are often used to affirm the safety of riot control agents are outdated, going back to the 1950s and 1960s. It should also be noted that most of the data available on the effects of tear gas come primarily from studies conducted on healthy, young male populations, and less is known on the extent of CS gas exposure on pregnant women, children, and the elderly.


More recent studies by the U.S. Army and other research institutions are beginning to find a connection to repeated CS gas exposure and long-term respiratory issues. In a 2014 study conducted by the U.S. Army, it was found that recruits who had prolonged and repeated exposure to CS gas experienced increased risks of contracting common illnesses like the cold or the flu. In the age of COVID-19, these risks have only increased.

As Dr. Sven Jordt, a researcher from Duke University who studies the effects of riot control agents on the respiratory system explains, “We have a lot of antiviral defenses that can inactivate viruses and prevent them from entering cells. These are depleted by inhalation of tear gas and also compromised.”

Newer research has found that the effects of tear gas may go beyond the respiratory system, with a recent study reporting disruptions and abnormalities in menstrual cycles linked to CS gas exposure. Cases of severe epidermal reactions and serious ocular injuries have also been cited.

The combination of intense coughing and large crowds likely helped spread the virus last summer experts say (AP).

The use of tear gas amidst the ongoing COVID-19 pandemic is thus a concern many have started voicing. While it is still unknown if COVID-19 is among the group of diseases an individual exposed to teargas may be more susceptible to, other research has linked CS gas and many of the products produced through combustion of the canisters to a worsened antiviral defense in the lungs. And there is ample research to suggest that the use of CS gas can exacerbate the symptoms of those who have already contracted COVID-19. “These exposures to tear gas would increase the risk of progression from the asymptomatic infection, to a symptomatic disease,” Dr. John Balmes, a pulmonologist at the University of California at San Francisco and an expert with the American Thoracic Society, explains. High concentrations of CS gas can lead to pulmonary edema (excess fluid in the lungs) and apnea (interruption or cessation of breathing), as a result of the CS gas killing lung tissue. The effects are similar to severe symptoms of COVID-19.


Beyond just exacerbating the symptoms of COVID-19, however, the use of tear gas and other similar riot control agents may increase the spread risk of airborne diseases. Those who are affected by tear gas are likely to cough more, pull down their masks, or touch their faces in response to the irritation caused by the chemicals.

And since riot control agents are typically used on large crowds, this combination provides the perfect conditions for spreading an airborne virus.

Because of the abundance of research that indicates the dangers of riot control agents, many professionals, including the American Thoracic Society, have requested police stop using tear gas. While some areas like Columbus, Ohio, have enforced bans on tear gas usage by the police, the situation varies for different cities across the U.S. But as we develop a greater understanding of the effects of tear gas through continued research, it is entirely possible that tear gas could eventually become a thing of the past.


If you are planning to protest or have been exposed to tear gas, you may visit https://emergency.cdc.gov/agent/riotcontrol/factsheet.asp for information on how to treat tear gas exposure.

Cassandra He is a freshman at MIT studying biomedical engineering. She writes about computing, biology, and innovation.


This piece was edited by Will Cover, a sophomore at Rice University studying public policy originally from Columbia, Missouri.


Cover: PBS

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