A Project of The Annenberg Public Policy Center

The Semantics of ‘Tear Gas’ Versus ‘Pepper Spray’


Democratic politicians have criticized President Donald Trump for the use of “tear gas” to disperse protesters near the White House on June 1 before Trump walked to St. John’s Episcopal Church to pose for photos with a Bible. The president countered, “They didn’t use tear gas.”

U.S. Park Police says officers used “pepper balls,” not “tear gas.” It’s true pepper balls, which contain a pepper spray-like irritant, have a different makeup than another chemical typical referred to as “tear gas” (and which USPP specifically says it didn’t use). But some sources consider pepper spray a type of tear gas, while others say both chemicals have the same effect on people.

According to the Scientific American and the Centers for Disease Control and Prevention, pepper spray is a type of “tear gas” or “riot control agent.”

Dr. Ranit Mishori, senior medical adviser for Physicians for Human Rights and a Georgetown University professor of family medicine, told us in an email: “Tear gas and pepper spray both belong to a class of crowd-control weapons known as chemical irritants.” The chemical makeup is different, but the impact on people is similar. “During a protest, it is impossible to tell what chemical is being used as the clinical manifestations are the same.”

Trump’s reelection campaign has claimed the media was “falsely reporting” that U.S. Park Police used “tear gas,” and in a Fox News Radio interview on June 3, Trump said the stories about clearing out the protesters with “tear gas” were “fake. They didn’t use tear gas. They didn’t use. They moved them out.”

Trump didn’t mention the “pepper balls.” Both chemical irritants cause, according to Mishori, “sometimes severe irritation to mucous membranes (e.g eyes, mouth, nasal passages, lungs), causing people to experience burning sensations on the skin and in the eyes, tearing, coughing, sneezing, difficulty breathing, nausea, vomiting, disorientation.”

The incident occurred June 1. Shortly before Trump delivered remarks in the Rose Garden, U.S. Park Police began clearing out protesters in Lafayette Square, just north of the White House.

The Park Police Acting Chief Gregory T. Monahan said in a statement: “At approximately 6:33 pm, violent protestors on H Street NW began throwing projectiles including bricks, frozen water bottles and caustic liquids,” which caused USPP to issue “three warnings over a loudspeaker” and then clear the area. Reporters who were on the ground have said they didn’t see projectiles being thrown, or described the crowd as “peaceful” or “largely peaceful.”

Regardless of the impetus, USPP used force to move the protesters, including, as can be seen in multiple videos, loud flashes, smoke and officers on horseback.

At about 6:50 p.m., Trump ended his speech, saying, “And now I’m going to pay my respects to a very, very special place.” He and other administration officials then walked to St. John’s Episcopal Church, across the street from Lafayette Square, where Trump posed for photos while holding up a Bible.

Trump has been criticized for the chain of events. “When peaceful protesters are dispersed by the order of the president from the doorstep of the people’s house, the White House — using tear gas and flash grenades — in order to stage a photo op at a noble church, we can be forgiven for believing that the president is more interested in power than in principle,” presumptive Democratic presidential nominee Joe Biden, said.

Democratic Sen. Kamala Harris also said in a June 2 press conference, “And then last night I watched as President Trump, having gassed peaceful protesters just so he could do this photo op, then he went on to teargas priests who were helping protesters in Lafayette Park.”

Trump has said he didn’t order the removal of the protesters. “Now, when I went, I didn’t say, ‘Oh, move them out.’ I didn’t know who was there. I figured I was going to walk over the church very nearby,” Trump told Fox News Radio. In a press briefing on June 3, White House Press Secretary Kayleigh McEnany said Attorney General William Barr ordered the clearing of the area the morning of June 1 “to expand the perimeter by one block on each side,” adding that Barr was “surprised” it hadn’t been done yet when he got to the White House and told officers in the “late afternoon” to do it.

In an interview with former White House Press Secretary Sean Spicer for Newsmax, Trump described the photo op as a spontaneous event and downplayed any use of force to remove protesters. “The military moved them back. I guess they just reported there were no, what would you call them, the rubber bullets or whatever. There was none of that used. They just moved them back,” he said. “They didn’t know until just shortly before that I was going there. Somebody suggested it, and I said, ‘Let’s go, let’s walk.’ We walked from the White House and I think everything was handled pretty well.”

There are many unanswered questions about the events. We’ll focus on the disagreement over whether “tear gas” was used, as many media outlets that covered the incident reported.

Chemical Irritants

In Monahan’s statement, he said: “No tear gas was used by USPP officers or other assisting law enforcement partners to close the area at Lafayette Park.” After a reporter with Washington, D.C.’s WUSA9 TV reported on the canisters he said he picked up off the street after they were launched on June 1, USPP updated its statement to say it and “and other assisting law enforcement partners” didn’t use those “OC Skat Shells,” either. Such shells contain Oleoresin Capsicum – an irritant derived from pepper plants.

But Monahan said USPP did use “smoke canisters and pepper balls.” USPP spokesman Sgt. Eduardo Delgado told us: “We did not use CS or chlorobenzalmalononitrile, commonly referred to as ‘tear gas’ which is often used as a non-lethal option in law enforcement. I am unaware of the brand of pepperball used.”

Thomas Kearney, associate dean and professor in the Department of Clinical Pharmacy at the University of California San Francisco and co-author of a 2014 study on pepper spray injuries, told us he didn’t have knowledge about these particular “pepper ball” devices, but that the USPP “was probably referring to an OC containing lacrimator. Oleoresin Capsicum (OC) is the active ingredient of peppers and activates the TRPV1 pain receptor. Whereas CS & CN have different receptors and were more toxic,” he said in an email, referring to chloroacetophenone.

He said he believed the terms were used “interchangeably- tear gas vs lacrimator.” A “lacrimator,” of course, is a substance that produces tears, and both CS and OC do that.

In a November 2018 article, titled “How Tear Gas Works: A Rundown of the Chemicals Used on Crowds,” the Scientific American said tear gas agents “can be classified into two broad categories” based on the pain receptors they activate. CS, the chemical Delgado said USPP didn’t use, is the first category of “TRPA1-activating agents,” which also include “CR gas (dibenzoxazepine) and CN gas (chloroacetophenone, also used in bear spray),” Scientific American said.

“The second category of tear gas agents are pepper sprays and activate the TRPV1 pain receptor,” the article said. “These are mostly derived from capsaicin, the spice compound in chili peppers. There are two compounds in common use in this category: OC gas, a concentrated solution of natural capsaicin, and PAVA, a mix of synthetic capsaicin also used by U.S. Customs and Border Protection.”

Dr. Rohini Haar, an emergency physician, epidemiology lecturer and research fellow at the Human Rights Center at the University of California Berkeley’s School of Law, echoed Kearney’s comment that the pepper sprays aren’t as toxic as the CS/CN chemicals. The pepper spray category “has fewer chemical or allergic reactions, but it’s also an oil so it’s much harder to get off and can last longer,” Haar, also an adviser for Physicians for Human Rights who has studied injuries caused by these agents, told Scientific American. “It can also cause corneal abrasions if you’re shooting it directly into someone’s eyes.”

The CDC calls these agents “riot control agents” in a fact sheet, saying they are “sometimes referred to as ‘tear gas'” and “are chemical compounds that temporarily make people unable to function by causing irritation to the eyes, mouth, throat, lungs, and skin.” The CDC mentions “pepper spray” as one of those agents. “Riot control agents are used by law enforcement officials for crowd control and by individuals and the general public for personal protection (for example, pepper spray).”

Mishori told us the difference between the pepper balls and CS “is in the chemical makeup, but the physiological effects are similar, in terms of the chemical irritation. Pepper balls are fired from rifles and can also cause severe harm due to traumatic projectile injuries when the ‘balls’ or canisters fired at protesters hit people in the head, neck, or face. Such injuries can cause blindness, for example, if the eyes are hit.”

She criticized the use of these agents, saying they are called “non-lethal” but severe injuries and even deaths have been documented. “Deploying chemical irritants against peaceful protestors in a public park to clear a path for President Trump to pose for photos was an egregious, dangerous, and excessive abuse of force,” Mishori said.

In a 2018 report, Physicians for Human Rights found: “A systematic review of medical literature documenting the health effects of chemical irritants identified 5,131 people who suffered injuries; two of these people died and 70 suffered permanent disabilities.” The canisters were the cause of one of the deaths and several injuries.

Kearney’s 2014 study reviewed 10 years of pepper spray exposures reported to a poison control system (from 2002 to 2011) and found “a low 1 in 15 potential risk for more severe adverse health effects in persons exposed to pepper spray that warranted a medical evaluation. The risk was highest when used for training of law enforcement personnel and involved severe ocular symptoms.”

Chemical irritants are actually banned from use in war by the Chemical Weapons Convention, Mishori and Kearney said, but the convention includes an exception for “[l]aw enforcement including domestic riot control purposes.” Trump signed legislation last year that banned the commercial exportation of certain riot-control devices to Hong Kong police. The list of “covered munitions” included “pepper balls.”

Trump may object to the term “tear gas” because it may connote a harsher tactic than using “pepper balls” or “pepper spray.” But Mishori said it would be “impossible” to discern which chemical was being used during the protest, since they cause the same health impacts. The president’s claim that law enforcement “didn’t use tear gas,” without mentioning the pepper balls, leaves the false impression that no chemical agents were used. The USPP has admitted they were.

It’s also unclear whether other law enforcement entities used chemical irritants. When we called the National Guard Bureau press office about this, a spokesman referred us to Defense Secretary Mark Esper’s statement that “National Guard forces did not fire rubber bullets or tear gas into the crowd.”

Nathan Baca, an investigative reporter with WUSA9 TV, reported that WUSA crews also picked up canisters that contained a “CS agent” on June 1, but USPP told the station it didn’t use those canisters, either. We don’t know if those canisters could have been used before the June 1 incident, as there were some type of chemical agents used on prior nights.