Secondary aerosolization of viable Bacillus anthracis spores in a contaminated US Senate Office.

Context: Bioterrorist attacks involving letters and mail-handling systems in Washington, DC, resulted in Bacillus anthracis (anthrax) spore contamination in the Hart Senate Office Building and other facilities in the US Capitol's vicinity.

Objective: To provide information about the nature and extent of indoor secondary aerosolization of B anthracis spores.

Design: Stationary and personal air samples, surface dust, and swab samples were collected under semiquiescent (minimal activities) and then simulated active office conditions to estimate secondary aerosolization of B anthracis spores.