Inadvertent laboratory exposure to Bacillus anthracis--California, 2004

On June 9, 2004, the California Department of Health Services (CDHS) was notified of possible inadvertent exposure to Bacillus anthracis spores at Children's Hospital Oakland Research Institute (CHORI), where workers were evaluating the immune response of mice to B. anthracis. This report summarizes the subsequent investigation by CDHS and CDC, including assessment of exposures, administration of postexposure chemoprophylaxis, and serologic testing of potentially exposed workers. The findings underscore the importance of using appropriate biosafety practices and performing adequate sterility testing when working with material believed to contain inactivated B. anthracis organisms.