The Wild Wild West of Tear Gas Regulation

Last summer, images of tear gas-laden protestors engulfed the news cycle amidst clashes with local police. When Paula Rogish attended a protest in May of 2020 in front of Austin City Hall, she was not surprised when she and her partner were sprayed with tear gas. She was surprised with how long her symptoms lasted: “I woke up with difficulty breathing almost every night for 2-3 weeks and had to use my rescue inhaler.” Paula, who for most of her life had moderate asthma, has since bought a nebulizer machine to alleviate her now-severe symptoms.

The outcomes of Paula’s exposure to tear gas are less shocking if you consider the historical roots: tear gas was initially designed for chemical warfare until its wartime use was internationally outlawed by the 1925 Geneva Convention – a stark contrast to its current use for “riot mitigation” on civilians. The use of tear gas as a crowd control device is often justified by its classification as a “sublethal” weapon – but is sublethal the same thing as safe?

We found that the notion that tear gas is safe doesn’t come from studies proving that it is – it comes from the fact that there isn’t much evidence that it’s unsafe, which comes from the fact there is hardly any research on tear gas at all. The few studies that do exist are largely outdated, and many of them were conducted in the U.S. armed forces – a primarily young, male, and healthy population that doesn’t represent the general population. (Not to mention, privacy rights of the military often complicate the evaluation of their methods and results.) The need for formal research is a dereliction that fits a pervasive pattern in clinical research of insufficient representation of women and nonwhite populations. Issues with representation are ongoing: after numerous reports that exposure to tear gas impacts reproductive health (i.e., menstrual dysregulation, miscarriages), the first study demonstrating associations between exposure to tear gas and menstrual irregularities was completed this past week.

“Without robust and representative studies, how can tear gas be reasonably considered safe for use on civilians when it was internationally deemed too hazardous for soldiers?”

How can we know so little about the effects of tear gas on the body? After going down a rabbit hole of government agencies, reports, and acts that all seemed to pass the buck to someone else, it quickly became clear that there is functionally zero accountability around tear gas production and use. In our recent policy memo published in the Journal of Science Policy and Governance, we argue that formally placing tear gas under the purview of the FDA would provide such accountability. The FDA approval process would require comprehensive research into how tear gas affects the health of our citizens – including women and those with preexisting conditions who have been excluded from previous research. Without robust and representative studies, how can tear gas be reasonably considered safe for use on civilians when it was internationally deemed too hazardous for soldiers?

Unrepresentative and Understudied

Whereas the name “tear gas” suggests a gaseous substance, the term usually refers to the powdery compounds OC (oleoresin capsicum) and CS (2-chlorobenzalmalonitrile) that are mixed with various liquid solvents in order to be aerosolized and carried through the air. When OC and CS enter your system, they primarily target the respiratory tract, gastrointestinal system, eyes, and skin to cause their characteristically painful effects.

“[…] the CDC’s website mentions that prolonged tear gas exposure can cause respiratory issues like asthma.”

What happens in your cells once tear gas enters your body? Here, there is actually a good amount of related molecular biology research that may explain why encounters with tear gas are so consequential. CS and OC bind to ion channels in the Transient Receptor Potential (TRP) family, which are found in pain-sensing nerve cells throughout the body. These same receptors play a role in animal models of several medical conditions, including asthma, dermatitis, cardiac arrhythmias, and diabetes. Certainly, these animal studies warrant some formal research into whether tear gas could be particularly harmful for people with these underlying conditions. In fact, the American Lung Association has said that people with preexisting respiratory conditions have a higher risk of severe reactions from tear gas, and the CDC’s website mentions that prolonged tear gas exposure can cause respiratory issues like asthma. 

While the environmental triggers for Paula’s asthma have not changed since she was sprayed with tear gas – she’s still sensitive to pollen and cold air – her asthma has since increased in severity: “It’s much easier for my asthma to get triggered and it happens much more often. Before I had pretty mild to moderate asthma, and now it is moderate to severe. I used to just be able to use one preventative inhaler, and one rescue inhaler, and now I have both of those as well as a nebulizer that I keep at home for when I have a really bad attack.”

The fact that the effects of tear gas are largely unknown is particularly worrisome since tear gas does not only impact those in the line of fire: in gaseous form, it can indiscriminately impact bystanders and residents of nearby neighborhoods. With a reported dispersion area of up to about the size of a tennis court (60 to 300 m2), these chemicals can easily waft into surrounding homes and apartments, with residue settling onto belongings, food, and exposed surfaces. In one report, tear gas from a nearby protest wafted into a Seattle family’s home, causing their 3-month-old infant to wake up in the night, “bright red and foaming at the mouth.”

Unrestricted and Unregulated

At this point, you may be wondering: what about the manufacturing of tear gas? Surely this must be tightly regulated, even if its deployment isn’t?

Well, the manufacturing of tear gas – the ingredients, chemical composition, concentrations, etc. – is in fact not regulated by any federal agency in the United States. A stunning article by the Associated Press details their search for a governing body that resulted in a game of “hot potato” where several federal regulatory health agencies directed journalists back and forth until it was clear that no agency claimed oversight.

The closest thing to a regulatory body or document is likely the 1972 Federal Advisory Committee Act, which formed a national committee (the NAC/AEGL) to determine what concentrations of toxic chemicals, like CS, would be safe for use. The report – which didn’t come out until 2014 – could not determine a minimum concentration of CS gas that would have no guaranteed irreversible health effects. This means that, according to this report, any exposure to CS gas, however small, is potentially harmful. The report did not name an agency that would be responsible for regulation of manufacturing, deployment, or accountability in cases of abuse. The lack of comprehensive research on the public health impacts of tear gas can presumably be connected back to this fact that no government agency is directly responsible for its regulation.

Many agencies exist to regulate and maintain health and safety standards, whether relating to the environment (Environmental Protection Agency, EPA), the workplace (Occupational Safety and Health Administration, OSHA), or consumable products (Food and Drug Administration, FDA). Through a comprehensive research and review process, these entities decide how much and what kinds of chemicals (e.g., in medicines, cosmetics, pesticides, tobacco products) and what kinds of workplace practices (e.g., proper storage of chemicals in research labs) are safe.

When it comes to tear gas, proper regulation would not only require a formal and comprehensive analysis of its effects on the health of our citizens, but it would also institute oversight over both the manufacturing and deployment of tear gas. Unsafe working conditions have been documented at several factories in the US, the world’s primary manufacturer of tear gas. Additionally, close-range projectile deployment of tear gas is prohibited, but its occurrence has resulted in broken cartilage and bones, blindness, and traumatic brain injury.

“The exclusion of women, children, the elderly, and those with underlying health conditions is especially striking when you consider that these are the very people for whom tear gas may pose the biggest risks.

Time to bring in the Feds

In our policy memo, we argue that one solution to the lack of regulation and oversight is to place tear gas under the jurisdiction of the FDA, which would require federal legislation to expand their authority. Luckily, this has been done before when Congress passed the Family Smoking Prevention and Tobacco Control Act of 2009, which allowed the FDA to begin regulating the tobacco industry. Placing tear gas under the jurisdiction of the FDA would provide a mechanism for comprehensive and representative research. Simultaneously, expanding the FDA’s role would send the message that the U.S. federal government prioritizes the safety of its citizens as they exercise their First Amendment right to peaceful assembly.

Our job as scientists is not to draw up regulations to dictate how chemical substances like tear gas are used or manufactured. But, we do think that the lack of scientific research on tear gas – a potent chemical weapon banned internationally for use in war – is an alarming oversight and poses tangible risks to society. The exclusion of women, children, the elderly, and those with underlying health conditions is especially striking when you consider that these are the very people for whom tear gas may pose the biggest risks. We find it unacceptable to assume that tear gas is safe to be used on the general public without a formal analysis.


Written by Yuki Hebner, Zoe Guttman, and Lauren Wagner.
Edited by Holly Hake.


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Yuki Hebner

Yuki Hebner

Yuki earned her BA and MA in Molecular Biology and Biochemistry at Wesleyan University before starting her PhD in Gene Regulation, Epigenomics, and Transcriptomics at UCLA. In the lab of Dr. de la Torre-Ubieta, she studies chromatin remodeling during human cortical development to understand the epigenetic mechanisms underlying psychiatric disease. She is passionate about exploring chromatin biology and neurodevelopment, and is also motivated to advocate for the incorporation of the existing science to help guide problem solving in society. Yuki is the VP of the Science Policy Group at UCLA.