anthrax scare dc house speaker hastert decided close entire capitol complex including office buildings house side end working day today monday precautionary move allow special agents germ experts conduct sweep ventilation systems remaining unopened mail senate side expected also confirmed anthrax laden letter sent senate majority leader daschle office particularly potent high grade military quality anthrax quickly spread opened 29 staff dachle office mail room tested positive anthrax spores found ventilation system hart building daschle office located one tunnels leading capitol even hint military grade anthrax came iraq strike u iraq another possibility anthrax russian origin somehow illicitly acquired al qaeda taliban second anthrax letter new outbreak anthrax evidence anthrax spores spreading committee rooms located senate house buildings pre cautionary move house speaker hastert though way diminishes ugly situation