Dear Attorney General Pepper Spray Is A Chemical Irritant

October 7, 2020

Despite Attorney General William Barr’s assertions to the contrary, pepper spray is a chemical.

On June 7, Margaret Brennan of CBS News interviewed Barr on Face the Nation to bring this Chemistry 101 lesson to life. In the interview, Brennan questioned Barr about the decision to actively remove peaceful protesters from Lafayette Park in Washington, D.C., before President Donald Trump took a photo walk in St. John’s Church.

In the interview, Barr denied that police used tear gas on the protesters in the park. Brennan went on to say, “The park police had [sic] said that there was a chemical irritant.” Barr interrupted and said, “No, there was no chemical irritant. The pepper spray is not a chemical irritant. It’s not a chemical.”

The word “chemical” has a very broad definition. It basically means anything that has a specific molecular composition and structure. Water is a chemical because no matter how you slice it, it’s made up of two hydrogen atoms and one oxygen atom arranged in a specific form. So yes, pepper spray is a chemical. The active ingredient is capsaicin, which is the chemical that gives heat to peppers. Its chemical formula is C18H27NO3 (that is, each molecule has 18 carbon atoms, 27 hydrogen atoms, one nitrogen atom, and three oxygen atoms).

With Trump about to speak in the Rose Garden, the protesters on H and 16th streets were suddenly and unusually aggressively dispersed. In the space of about 10 minutes, they had unleashed everything from tear gas to flash bang grenades, causing hundreds of people to make a frantic retreat to 16th Street.

Pepper spray is also, unmistakably, an irritant. As Live Science previously reported, capsaicin may have evolved as an antifungal agent, according to a 2008 study. But when capsaicin comes in contact with mucous membranes, it triggers pain receptors and produces a burning sensation. In response, the mucous membranes produce mucus and tears in an effort to wash away the irritant. It’s this physical response that makes pepper spray an effective but dangerous way to calm people down. People have trouble breathing, their vision becomes blurred as tear ducts overflow, and their eyelids swell.

In addition to the unscientific sound bites about the chemical, Barr tried to downplay the effectiveness of crowd control used in Washington, D.C. After talking about pepper spray, he immediately backtracked and said that it was pepper balls, not pepper spray, that were used on the protesters. Pepper balls, however, are also a chemical irritant. They’re essentially paint balls filled with capsaicin, a product containing capsaicin that’s also extracted from chili peppers The product is delivered differently than pepper spray (which comes out of a can), but the result is the same.

Barr also attempts to distinguish pepper spray from “tear gas,” which gets into a semantic argument about chemicals. According to the Centers for Disease Control and Prevention, the most common chemicals classified as “tear gas” are chloroacetophenone (CN) and chlorobenzylidene-propionitrile (CS), both of which can cause large amounts of tearing in the eyes and can damage tissue. However, these chemicals are not found in pepper spray. (CN is also deadly at high doses, according to a 2003 paper in the journal Toxicological Review.)On June 5, park police told Vox that denying the use of tear gas to clean up the park was a “mistake.”

“The point is that we admit to using what we used,” Sgt. Eduardo Delgado, a spokesman for the U.S. Park Police, told Vox.” I don’t think the term ‘tear gas’ is important anymore. It was a mistake for us to use ‘tear gas’ because we just assumed people would think of CS or CN.”

Delgado went on to say that the park police used smoke bombs and pepper balls on the protesters.” I’m not saying it wasn’t tear gas, but I’m just saying that we used a pepper ball that shoots powder…. Everyone got off topic and said, ‘Well, aren’t pepper balls tear gas?’ It’s like, ‘I don’t know.’ I’m just telling you what we used, we didn’t use.”