and the capital physician, i'll have more to say about our own circumstances in the office after dan nichols of the capital police and dr. john isold, our capital physician, speak to questions directly as to the letter itself. >> lieutenant dan nichols, spokesman of the united states capital police. approximately 10:30, a letter was received in the hart senate office building which contained a powdery substance. there was an exposure when the letter was opened. following protocols the staff who opened the letter immediately contacted u.s. capital police. the officers respond to the scene isolated these situations and according to our protocols we conducted field tests. the first field test became back as positive for anthrax. we did a second field test and that came back also as positive for anthrax. >> they hoped it could be contained in a small area but after a day they began to be concerned the anthrax could be contained so all of the senate staff who work in this building are required to come to this room to have themselves swabbed to test to see whether or not there was any chance they