Here’s why tear gas could worsen symptoms of coronavirus — and prompt more spread

·6 min read
Some protesters move away as police shoot tear gas and flash grenades to disperse the crowd on Broadway near the Oakland Police Department during the fourth day of protests over George Floyd's death by the Minneapolis police in Oakland, CA (Ray Chavez/Digital First Media/East Bay Times via Getty Images)
Protesters move away as police shoot tear gas near the Oakland Police Department on June 1. Pulmonologists say the chemical may be putting people more at risk during COVID-19. (Photo: Ray Chavez/Digital First Media/East Bay Times via Getty Images)

As protests over police killings of black people continue to erupt nationwide, New Orleans has become the latest city to use tear gas, a powerful chemical irritant, to break up crowds. "The [New Orleans Police Department] deployed tear gas tonight to disperse protesters...” NOPD tweeted Wednesday night. The move comes on the heels of similar incidents in Oakland, Calif.; Minneapolis; and Washington D.C. — where protestors were seen “coughing and limping, their eyes burning amid clouds of smoke.”

While some departments have confirmed using tear gas, others are pushing back on the characterization, including the U.S. Park Police in D.C., which wrote in an email to Yahoo Life saying that the department “did not use tear gas” on protestors and that “the only things deployed were smoke canisters and pepper balls which contain a powder.”

“Tear gas” according to the Centers for Disease Control and Prevention, is not one single product, but a term used to describe riot-control agents. The CDC defines these as “chemical compounds that temporarily make people unable to function by causing irritation to the eyes, mouth, throat, lungs, and skin.” The most widely used chemical in tear gas is 2-Chlorobenzalmalononitrile or CS, which was confirmed to be a method used by police in Ferguson, Mo. following the killing of Michael Brown.

Whether or not police departments are now using CS or another one of the more than 15 chemicals that qualify as riot control agents, multiple doctors tell Yahoo Life that the symptoms being described by protestors (“burning eyes and throats”) signal the use of a chemical irritant that could make the COVID-19 pandemic worse.

Dr. Jonathan Parsons, a pulmonologist at the Ohio State University Wexner Medical Center, describes tear gas as an aerosol, formed by mixing a powder with liquid then releasing it through canisters. The chemical agent, he says, sets off a chain reaction in the body that causes immediate, excruciating discomfort. “Tear gas activates pain receptors leading to intense and burning pain,” Parsons tells Yahoo Life. “It can cause pain and burning in the eyes, mucous membranes, throat, lungs and skin.”

While Parsons notes that there are no studies yet on whether tear gas may have an effect on COVID-19 patients, previous research suggests it might. Satya Achanta, an assistant professor of anesthesiology at Duke University School of Medicine, has been studying tear gas for nearly a decade. He’s been concerned watching the events unfold nationwide, given what he’s seen in earlier reports.

“Published studies show that when people are having underlying respiratory issues, they're more prone to get more toxic effects of tear gas or any toxic inhalation hazardous agents,” Achanta tells Yahoo Life. “So, in my opinion, and the best scientific literature, when the tear gets is [deployed] on COVID-19 patients, or even asymptomatic carriers, they may experience exacerbated symptoms.”

Achanta elaborates on what could potentially happen. “There may be some COVID-19 patients among the protesters who may be early on in their symptoms ...but if they have it, their respiratory system might already be partially inflamed and they may experience more serious effects,” he says. “If there is an asymptomatic carrier — so he's infected, but he's not showing any symptoms — when he's exposed to tear gas it causes inflammation to the airways. So, in that situation, there will be some stress and immunity compromise ... in that case, the asymptomatic carrier may become a symptomatic patient.”

Previous studies, he adds, have shown increased susceptibility of healthy military personnel to airway infections following tear gas exposure during chemical, biological, radiological, and nuclear (CBRN) defense mask confidence training sessions.

Nina Shapiro, MD, director of Pediatric Ear, Nose and Throat at the UCLA Mattel Children’s Hospital and a professor at the David Geffen School of Medicine, echoes Achanta’s concerns. “If an individual develops coronavirus infection and already has inflammation of their airways, they are more likely to suffer more severe complications from the illness [from exposure to tear gas],” says Shapiro. “One study showed that it can cause acute lung symptoms, such as coughing, chest tightness, wheezing, and respiratory difficulties. Especially if inhaled more significantly, it can cause prolonged inflammation in the respiratory tract, and act as a set-up for lung and other respiratory illnesses.”

On top of the potential to worsen symptoms, she also worries about the potential that the symptoms may cause the virus to spread more easily. “Even after exposure to CS, many individuals continue to cough for days to weeks. If they are already an asymptomatic or presymptomatic carrier of COVID-19, they are more likely to spread it,” she says. “Those exposed will be coughing, sneezing, and tearing, all of which are potential means of spreading coronavirus to others in proximity.”

Both Achanta and Shapiro believe that the use of tear gas may also increase the risk of contraction for protestors who do not already have COVID-19. “Any inflammation in the airway, including the eyes, nose, mouth, and windpipe/lungs makes it easier for viruses and bacteria to replicate,” says Shapiro. Achanta explains that our airways contain cilia, hair-like structures that work by removing excessive mucus and other debris. Tear gas interferes with this. “When they're exposed to tear gas, the airway mucus clearance is hampered,” says Achanta. “So in that situation, the virus can have better access to get into the system.”

As protests continue nationwide, he urges those joining to take further precautionary measures. “Everybody should wear minimum mask and safety goggles because we’ve seen that police are also using rubber pellets,” Achanta advises. “People should cover themselves as completely as possible by wearing full sleeve shirts and full pants. And then they should move to higher ground ... because tear gas, although it is called a gas, these are the fine solid particles. They settle close to ground; they are heavier than air.”

For the latest coronavirus news and updates, follow along at According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.

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