US Park Police have disputed reports claiming “tear gas” was used on peaceful protestors in Lafayette Square on the basis that they used “oleoresins capsicum” (OC), rather than 2-chlorobenzalmalononitrile (CS) or chloroacetophenone (CN). Even this much appears to have been a lie, but nonetheless this is their story and as of yet they’re sticking to it.1
In effect, the argument of Park Police was that OC doesn’t count as “tear gas,” so claims that “tear gas” was used are incorrect. As established in another Q&A, that definition of “tear gas” doesn’t match the CDC’s, or for that matter, Wikipedia’s, which lists OC in the lede for “tear gas” (and has done so for a decade).
Sgt. Eduardo Delgado, a spokeman for US Park Police, addressed this discrepancy. As Vox reports,
A US Park Police spokesperson said Friday in an interview it was a “mistake” to insist in a statement on Tuesday that the agency didn’t use tear gas the day before in a Washington, DC, park to disperse a crowd ahead of President Donald Trump’s photo op, explicitly noting that pepper balls shot by officials irritate the eyes and cause tears.
“The point is we admitted to using what we used,” Sgt. Eduardo Delgado said. “I think the term ‘tear gas’ doesn’t even matter anymore. It was a mistake on our part for using ‘tear gas’ because we just assumed people would think CS or CN,” two common forms of tear gas.
My question is, do we have any statements or publications by the US Park Police prior to this incident that define “tear gas” in this manner? (For that matter, do we have any prior statements by US Park Police that contradict this definition?) I am trying to gauge whether or not this is a consistent usage of “tear gas” by the US Park Police, if it is plausible that they could have “assumed” this is how the term would be understood, as claimed by Sgt. Delgado, or if instead this definition was chosen after the fact to conveniently explain this particular incident. (Of course, absence of evidence is not inherently evidence of absence, so a negative answer to this question doesn’t necessarily answer my broader curiosity, but a positive answer would.)
WUSA9 reporters literally found CS canisters still warm from being fired by federal officers after police had cleared one street (see WUSA9’s report), so even if OC doesn’t count as “tear gas,” CS definitely does. Vox reports that Sgt. Delgado denied that the Park Police were the ones launching these CS canisters, which is unlikely given eye-witness accounts but just barely plausible because federal law enforcement has been obfuscating their identities and affiliation during their actions in DC this week (widely reported, e.g. Politico).
Vox also reports that all of Sgt. Delgado’s statements were contradicted hours later by acting chief of the Park Police, Gregory Monahan, who claimed that Park Police didn’t use tear gas or OC. Acting Chief Monahan’s statement directly conflicts with eyewitness reports, observations by reporters who were present at the time, photographs and video taken of the incident, and physical evidence found at the scene, and is therefore being disregarded for the sake of this question.