CS gas is one particular type of tear gas.

The Washington Times claims today:

Tear gas used once a month at border under Obama

The same tear-gas agent that the Trump administration is taking heat for deploying against a border mob this weekend is actually used fairly frequently — including more than once a month during the later years of President Barack Obama’s administration, according to Homeland Security data.

U.S. Customs and Border Protection has used 2-chlorobenzylidene malononitrile, or CS, since 2010, and deployed it 26 times in fiscal 2012 and 27 times in 2013. The use dropped after that, but was still deployed three times in 2016, Mr. Obama’s final full year in office.

However, there is no link in the article to any official government data supporting this.

Has the USA used CS gas at the Mexican border since at least 2010?

  • 2
    In 2013 the San Diego Union-Tribune reported the use of pepper spray
    – user11643
    Nov 27, 2018 at 16:42
  • 2
    @fredsbend pepper spray is different from CS tear gas. CS tear gas is what Clinton used against the Texas children in 1993 csmonitor.com/1995/0726/26141.html
    – DavePhD
    Nov 27, 2018 at 16:45
  • 2
    @Dave I believe you're right, which is why it's a comment (of interest). This exact article was also cited by a border official to justify the recent use of the tear gas. Oddthinking's answer below calls it the same thing, which I've already challenged in the comments there.
    – user11643
    Nov 27, 2018 at 16:52
  • 1
    I have deleted my answer which referred to all types of tear gas AND edited the question to be clearer that only CS gas is relevant. (Hat-tip to @fredsbend for the feedback.)
    – Oddthinking
    Nov 28, 2018 at 0:36
  • 2
    @RonBeau: Your nomenclature is wrong. "Tear gas" is a collective term for all kinds of eye irritants, including but not limited to OC (oleoresin capsicum a.k.a. pepper spray), CS, CN etc.. As for persistency, capsaicin doesn't magically "break down" within an hour. If it did, your chili powder would likewise lose its "sting" in an hour as well. Bottom line, use "tear gas" only when unspecific, and use the more precise nomenclature (OC, CS, CN, ...) when referring to specific chemicals within the category.
    – DevSolar
    Nov 28, 2018 at 7:47

1 Answer 1


It appears to have been used before 2010.

I can't find sources for the "once a month" claim but there seems to be no lack of incidents involving US border forces firing tear gas into mexico.

This article, Dec 14, 2007


Mexico Says Border Patrol Assaulting Tijuana With Tear Gas


Mexican authorities and human rights groups said U.S. Border Patrol agents have begun launching pepper spray and tear gas from San Diego into densely populated Tijuana neighborhoods in response to escalating clashes with smugglers, it was reported Friday.

Border Patrol agents told the Los Angeles Times they have had to counter human traffickers' increasingly aggressive tactics -- especially near Tijuana's most notorious smuggling neighborhood of Colonia Libertad -- by ramping up their own use of force.

Agents have used pepper spray in the past, but usually aimed directly at the smugglers, according to the Times. The new tactics, which saturate large areas, have forced dozens of temporary evacuations and sent some residents to hospitals, witnesses told the newspaper.



Now the agency is responding with tear gas and powerful, pepper-spray weapons, including firing into Mexico.

The counteroffensive has drawn complaints that innocent families are being caught in the crossfire.

"A neighbor shouted, 'Stop it! There are children living here," said Esther Arias Medina, 41, who on Wednesday fled her Tijuana, Mexico, shanty with her 3-week-old grandson after the infant began coughing from smoke that seeped through the walls.

Jul 14, 2013


Texas DPS fires shots, launches tear gas across border


The Border Patrol agents then motioned toward Mexico, and Texas Rangers fired tear gas in that direction;


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