Updated: 4:50 p.m.

At about 2 p.m. D.C. police closed a couple of blocks of First Street Northeast near Union Station after a report of a suspicious package in the mail room at the American Psychological Association.

D.C. police arrived first, and D.C. Fire and Emergency Medical Services arrived soon after. Three people taken to the hospital did not show symptoms, according to D.C. Fire Public Information Officer Pete Piringer, and the building was partially evacuated. A hazardous materials team was still investigating shortly before 4 p.m.

“Initially police said it was a white, powdery substance,” Piringer said. “I’m not sure if that was actually the case.”

Sections of some nearby streets were closed, but North Capitol Street was still open, Piringer said. The American Psychological Association is at 750 First St. NE.

At 4:40 p.m., D.C. Fire tweeted that it was “clearing from 1st St NE” and the FBI would investigate the incident.