Oregon State Police say that the substance found at the state Department of Revenue early this morning is not dangerous.
The Salem Statesman-Journal reports that Lt. Michael Peterson says the area will soon open up to traffic.
The suspicious substance was deemed a non-threat and its consistency resembles that of a protein shake.
Officials have not yet confirmed what the substance is. Revenue employees are being let back into the building.
Early this morning, most of the building was cleared, after an employee opened an envelope in the mail room, and powder flew out.