For the information of people from out of state, Marietta is just north of Atlanta. This is happening at the Senator's main offices -- which for all essential purposes is right near Atlanta.
According to the radio, they're sending in some sophisticated testing equipment at this moment, and should know shortly what the stuff is. It sounds like it's going to turn out to be another hoax. But better safe than sorry.
BTW, Chambliss's office is NOT in Marietta but south of Smyrna in the Galleria area, inside the Perimeter. Less than a mile from my house.