A building in Dubuque was evacuated early this morning because of an anthrax scare.The Dubuque Postal Annex was evacuated for over three hours after a “strange, powdery substance” was found on a box. Between six and 12 employees were hustled out of the building at about 4:50 this morning as part of the new protocol for post offices. Law enforcement sealed off access to the entire building, which also houses some private businesses. The building and an adjacent parking lot were reopened about eight a.m.