Tear gas and pepper spray are designed to cause an immediate and intense reaction, but health experts have voiced that they can have lasting negative health effects.
“These are chemical weapons that are harmful to the human body and harmful to particularly vulnerable folks, like children,” says Asha Hassan, an epidemiologist at the University of Minnesota. “We know that tear gas causes tears, but it also causes other things that are a lot more severe,” she says.
However, the long-term effects are poorly understood. There have not been any large, systematic studies that focused on the lasting health effects caused by the exposure, says Anthony Szema, chair of the American Thoracic Society’s Section on Terrorism and Inhalation Disasters. However, there is known information about the components of tear gas and pepper spray, as well as their immediate effects.
The most common tear gas irritant used today is the compound 2-chlorobenzalmalononitrile, or CS. It is commonly used via exploding gas canisters and sometimes mixed into jets shot from water cannons. After one exposure, tear gas agents can trigger coughing, airway inflammation, and even lung collapse. Even minimal tear gas exposure can weaken respiratory functions, making people more susceptible to conditions such as bronchitis and pneumonia. Pepper spray typically contains oleoresin capsicum, or OC, which is a mixture of chili pepper extracts, such as capsaicin. It can be particularly harmful to people with allergies to peppers, says Szema, a pulmonologist at Hofstra University in Hempstead, N.Y.
Tear gas and pepper spray activate pain-sensing nerves on the skin, on the surface of the eye, and in our airways, says Sven Jordt, a pain and sensation researcher at Duke University. That triggers protective reflexes, such as coughing and tears, which can help wash away the chemicals. “But these agents are so potent that these reflexes become overwhelming, and [they] incapacitate you if you don’t remove yourself from the situation,” Jordt says. If a person is exposed to these chemicals, it is important for them to go to a well-ventilated area, away from the source. To lessen the pain, rinse their skin with soap and water and their eyes until clear of chemicals. Vulnerable populations to these chemicals include children, the elderly, people with asthma or COPD, and people in enclosed environments.
Much of what is known of the long-term respiratory risks of these chemicals is based on anecdotal evidence and studies conducted on healthy populations like military recruits. For example, a 2014 study of more than 6,000 army recruits found the odds of being diagnosed with an acute respiratory illness more than doubled when exposed to such chemicals during basic training. The study also found that higher amounts of exposure led to greater chances of illness. These chemicals, especially the CS agent, can damage the lining of the respiratory system, leading to fluids leaking into the lungs. Long-term and repeated exposure to these chemicals can cause lasting damage to the lungs. Furthermore, Hassan and her colleagues analyzed survey responses of around 1,200 people who had been exposed to chemical agents between 2020 and 2021. They reported that 83 percent of those exposed experience uterine cramping, breast tenderness, or early or late menstrual bleeding. As well as that, 10 of the 19 individuals who reported that they were pregnant when exposed reported a subsequent miscarriage. Even though this sample size is relatively small, it does raise questions about the effects such chemicals have on fertility.
Overall, even though there are not many studies focusing on the long term effects of tear gas and pepper spray, current research provides a broad understanding of what future issues could arise due to this exposure.
