The white powder that was in a letter at a Baltimore courthouse yesterday did not contain biological toxins, according to the Baltimore City Sheriff’s Office.

The room with the powder will be decontaminated and then reopened, according to the sheriff’s office.

Hazmat crews responded to the Cummings Courthouse at about 2:30 yesterday afternoon after a courthouse employee opened an envelope from a Maryland inmate. A white powder was inside, according to the sheriff’s office.

Three workers near the envelope when it was opened were isolated and taken to a hospital for testing, according to the sheriff’s office.

The sheriff’s office said it is leading a criminal investigation into the incident, and it’s working with the Baltimore City Police Department, The United States Postal Police, the ATF, the FBI, The Maryland Coordination and Analysis Center, and Department of Public Safety and Correctional Services.