The Bureau of Alcohol, Tobacco, Firearms and Explosives was evacuated Thursday afternoon due to a suspicious package left outside the agency's headquarters in Washington, D.C.

Several Metropolitan Police Department vehicles and emergency response officials were on the scene at 99 New York Avenue NW.

ATF HQ is evacuated due to a suspicious package & more information will be released at the appropriate time. pic.twitter.com/OqBruZg8kZ — ATF HQ (@ATFHQ) May 16, 2019

It has been determined that an employee opened an envelope w/ a suspicious liquid substance & Hazmat is responding accordingly. pic.twitter.com/xUsdBzQWXg — ATF HQ (@ATFHQ) May 16, 2019

"Update on ATF HQ evacuation: Hazmat is out, substance tested clear, will send to lab for further analysis," the agency wrote on Twitter 4:30 p.m. ET Thursday.

The ATF headquarters are located one block from one of the two entrances to the NoMa Metro stop, just north of Union Station.

Earlier this month, a suspicious package near Union Station prompted law enforcement to evacuate the Thurgood Marshall Federal Judiciary Building, a federal building directly next door to the transportation station.

NoMa metro station entrance is closed (near ATF) and looks like our buildings main in entrance is closed. Not #WorkingInDC pic.twitter.com/vRaK2lzvUE — Kevin Smith (@gokkgo1) May 16, 2019

ATF was formed in 1972. The federal law enforcement organization is part of the Justice Department. The agency's employees investigate federal offenses where guns, explosives, arson, bombings, alcohol, tobacco, and other related items have been used, sold, or transported across state lines.

The 4,700-person agency is led by acting Director Thomas Brandon.