Port Authority Police evacuated the 9/11 Memorial Plaza for about fifteen minutes on Tuesday night after a man sprinkled a suspicious white powder on the plaza that turned out to be salt, according to the NYPD.

The incident took place around 5:30 p.m.. Port Authority spokesman Joe Pantangelo said no arrests were made.

The man "said this was his way of honoring the deceased," Pantangelo told the Daily News. The 9/11 Memorial did not immediately respond to a request for further comment.

The site weathered criticism last spring, after a video went viral of guards breaking up a group of middle school students singing the National Anthem near the reflecting pools. The students hadn't acquired a necessary $35 permit for their musical performance, though a spokeswoman told Gothamist at the time that the guards "did not respond appropriately."

For further clarification on prohibited activities at the 9/11 Memorial—bathing, sleeping, gambling, lighting candles, asking questions—see Section XV of the Memorial's Visitor Rules and Regulations.