Tear gas is an expected, normalized part of protests today. But its use in international war is banned. How can that be? That’s just one of the questions we investigate in this episode. First, we take you through the long history of tear gas and its emergence alongside deadlier chemical weapons before discussing how its use became routine, fueled by industry interests. Then we delve into what’s in tear gas that causes the painful physical reaction and consider whether claims of non-toxicity are backed up by research (spoilers: not really). This is an info-packed episode that will leave you with many questions answered, but not all of those answers will be satisfying.
| History | Biology |
| Feigenbaum, Anna. Tear gas: From the battlefields of World War I to the streets of today. Verso Books, 2017. | Rothenberg, C., Achanta, S., Svendsen, E.R. and Jordt, S.E., 2016. Tear gas: an epidemiological and mechanistic reassessment. Annals of the New York Academy of Sciences, 1378(1), pp.96-107. |
| Schultz, John. No One Was Killed: The Democratic National Convention, August 1968. University of Chicago Press, 2020. | Olajos, E.J. and Salem, H., 2001. Riot control agents: pharmacology, toxicology, biochemistry and chemistry. Journal of Applied Toxicology: An International Journal, 21(5), pp.355-391. |
| Fries, Amos Alfred. Chemical warfare. McGraw-Hill book Company, Incorporated, 1921. | Brown, J.L., Lyons, C.E., Toddes, C., Monko, T. and Tyshynsky, R., 2021. Reevaluating tear gas toxicity and safety. Inhalation toxicology, 33(6-8), pp.205-220. |
| Waitt, Alden Harry. Gas Warfare; the Chemical Weapon: Its Use, and Protection Against it. Duell, Sloan and Pearce, 1942. | Haar, R.J., Iacopino, V., Ranadive, N., Weiser, S.D. and Dandu, M., 2017. Health impacts of chemical irritants used for crowd control: a systematic review of the injuries and deaths caused by tear gas and pepper spray. BMC public health, 17(1), p.831. |
| Bunn, George. “Banning poison gas and germ warfare: should the United States agree.” Wis. L. Rev. (1969): 375. | Carron, P.N. and Yersin, B., 2009. Management of the effects of exposure to tear gas. Bmj, 338. |
| Bunn, George. “Gas and germ warfare: international legal history and present status.” Proceedings of the National Academy of Sciences 65.1 (1970): 253-260. | Hu, H., Fine, J., Epstein, P., Kelsey, K., Reynolds, P. and Walker, B., 1989. Tear gas—harassing agent or toxic chemical weapon?. Jama, 262(5), pp.660-663. |
| Cachelin, Shala. “The suppression and othering of Black Lives Matter protests through tear gas.” Journal of Black Studies 54.6 (2023): 513-533. | Schep, L.J., Slaughter, R.J. and McBride, D.I., 2015. Riot control agents: the tear gases CN, CS and OC—a medical review. BMJ Military Health, 161(2), pp.94-99. |
| Gibson, Colonel Adelno. “Chemical Warfare as Developed During the World War—Probable Future Development.” Bulletin of the New York Academy of Medicine 13.7 (1937): 397. | Physicians for Human Rights: Preparing for, Protecting Against, and Treating Tear Gas and Other Chemical Irritant Exposure: A Protestor’s Guide. Available from: https://phr.org/our-work/resources/preparing-for-protecting-against-and-treating-tear-gas-and-other-chemical-irritant-exposure-a-protesters-guide/ |
| Horowitz, B. Zane. “Tear gas in America: Cry the beloved country.” Toxicology Communications 4.1 (2020): 59-61. | DeLuca, M.A., Chai, P.R., Goralnick, E. and Erickson, T.B., 2021. Five decades of global chemical terror attacks: data analysis to inform training and preparedness. Disaster medicine and public health preparedness, 15(6), pp.750-761. |
| Hu, Howard, et al. “Tear gas—harassing agent or toxic chemical weapon?.” Jama 262.5 (1989): 660-663. | Torgrimson-Ojerio, B.N., Mularski, K.S., Peyton, M.R., Keast, E.M., Hassan, A. and Ivlev, I., 2021. Health issues and healthcare utilization among adults who reported exposure to tear gas during 2020 Portland (OR) protests: a cross-sectional survey. BMC Public Health, 21(1), p.803. |
| Jacobs, Daniel, and Anthony Kovac. “The introduction of gas warfare and its medical response in world war one.” Journal of anesthesia history 6.4 (2020): 8-11. | Arbak, P., Başer, İ., Kumbasar, Ö.O., Ülger, F., Kılıçaslan, Z. and Evyapan, F., 2014. Long term effects of tear gases on respiratory system: analysis of 93 cases. The Scientific World Journal, 2014(1), p.963638. |
| Jones, Edgar. “Terror weapons: The British experience of gas and its treatment in the First World War.” War in History 21.3 (2014): 355-375. | Chung, S., Baum, C.R., Nyquist, A.C., Disaster Preparedness Advisory Council, Council on Environmental Health, Committee on Infectious Diseases, Krug, S.E., Fagbuyi, D.B., Fisher, M.C., Needle, S., Schonfeld, D.J., Lowry, J.A. and Ahdoot, S., 2020. Chemical-biological terrorism and its impact on children. Pediatrics, 145(2), p.e20193750. |
| Leff, Jack Rance. “An Alchemy of Smoke and Flame: The Politics of Tear Gas Use Against Social Movements in the United States.” (2024). | Amnesty International USA Documents Police Violence Against Protesters for Black Lives. https://www.amnestyusa.org/aiusa-documents-police-violence-against-protestors-for-black-lives/ |
| Linstrum, Erik. “Domesticating chemical weapons: Tear gas and the militarization of policing in the British Imperial World, 1919–1981.” The Journal of Modern History 91.3 (2019): 557-585. | MPR. TGear gas causes health concerns for Twin Cities residents. Jan 28,2026. https://www.mprnews.org/story/2026/01/28/tear-gas-health-concerns-twin-cities-residents |
| Mankoo, Alexander Chanan. A Historical Sociology of Teargas in Britain and the Empire, 1925-1965. Diss. UCL (University College London), 2019. | CNN Federal agents must limit tear gas for now at protests outside ICE building in Portland, Oregon, judge says. Feb 4, 2026 https://www.cnn.com/2026/02/04/us/portland-ice-protest-tear-gas |
| Waitt, Alden H. “No Super War Gas!.” Scientific American 153.6 (1935): 293-297. | Al Jazeera. At least 21 people killed in stampede, suffocation at GHF site in Gaza. July 16, 2025 https://www.aljazeera.com/news/2025/7/16/at-least-21-people-killed-in-stampede-suffocation-at-ghf-site-in-gaza |
| https://acleddata.com/report/future-stop-steal-post-election-trajectories-right-wing-mobilization-united-states | Amnesty International Tear Gas Incident Map. https://teargas.amnesty.org/#incident-map |
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