The Ramsey County Courthouse in St. Paul was closed Wednesday after employees discovered a powdery substance in an envelope.
Employees had to stay in the building until the Minnesota Department of Health determined there was no threat to the public. Visitors were barred.
No one was injured in the incident and there was no imminent threat to employee or public safety, according to the Ramsey County Sheriff's office.
The Courthouse reopens as usual Thursday morning, with the exception of the Violations Bureau, which will be closed until health department concludes its tests on the substance.