Hillary Clinton’s Downtown Brooklyn campaign headquarters were evacuated Friday amid a scare over a suspicious white powder, sources said.

The substance was first discovered when two interns opened the letter in Clinton’s midtown Manhattan office on 45th Street at 5 p.m., according to police sources.

The interns then took the letter to the 11th floor of Clinton’s campaign office in Downtown Brooklyn around 5:30 p.m., the sources said.

Four people were exposed to the substance and emergency services ordered the entire floor to be evacuated, the sources said.

The Secret Service and Office of Emergency Management were also on hand. It was unclear Friday night if the substance was dangerous.

Clinton campaign spokesman Glen Caplin said in a statement, “Preliminary testing by federal and local officials has found the substance to be non-hazardous.

The four individuals involved have reported no health issues and, following a full examination by medical personnel, were each released to go home.

Our office remained open throughout this period and will remain open without interruption tomorrow morning.”