A hazardous materials investigation turned out to be a false alarm after authorities swarmed Los Angeles City Hall following the discovery of a mysterious white powder.

The Los Angeles Fire Department, Los Angeles Police and LAPD’s HazMat Units responded to the scene around 2 p.m. after the unknown substance was found in a first floor mailroom.

Two city hall workers were evaluated by paramedics and transported to a hospital for further evaluation as a precaution after opening a package containing the unidentified substance. The workers didn’t show any signs or symptoms of illness, authorities said.

Footage from Sky5 showed a large number of first responders at the scene.

The mailroom and a few nearby businesses were evacuated by LAPD personnel and the LAPD Bomb Squad was also on the scene assisting authorities.

Los Angeles Street between Temple and First streets was shut down due to the investigation.

Around 6:15 p.m., LAFD officials said the scene was being cleared after it was determined the powder was not hazardous.

Authorities did not say what the substance ended up being, but the LAPD is continuing to investigate.

Streets were expected to be reopened shortly after first responders cleared the area.