Via the Centers for Disease Control: CDC Lab Determines Possible Anthrax Exposures: Staff Provided Antibiotics/Monitoring. Excerpt:
CDC announced today that approximately 75 Atlanta-based staff are being monitored or provided antibiotics because they may have been unintentionally exposed to live Bacillus anthracis (anthrax) after established safety practices were not followed.
Out of an abundance of caution, CDC is taking aggressive steps to protect the health of all involved, including providing protective courses of antibiotics for potentially exposed staff. Based on most of the potential exposure scenarios, the risk of infection is very low. Based on the review to date, CDC believes that other CDC staff, family members, and the general public are not at risk of exposure and do not need to take any protective action.
Although the investigation continues, early reports show that one of its Roybal campus biosafety level 3 (BSL3) labs was preparing B. anthracis samples for research in other CDC labs at lower biosafety levels to yield new means of detecting dangerous pathogens in environmental samples. However, the lab used a procedure that did not adequately inactivate the samples.
The potentially infectious samples were moved and used for experimentation in three CDC Roybal campus laboratories not equipped to handle live B. anthracis. Workers, believing the samples were inactivated, were not wearing adequate personal protective equipment while handling the material.
Lab safety investigators also determined that, sometime between June 6 and June 13, procedures used in two of the three labs may have aerosolized the spores. Environmental sampling was done, lab and hallway areas were decontaminated and laboratories will be re-opened when safe to operate.
The unintentional exposure was discovered June 13 when the original bacterial plates were gathered for disposal and B. anthracis colonies (live bacteria) were found on the plates. These plates had appeared negative for B. anthracis at the time samples were distributed to the other CDC laboratories. The review began immediately to assess the health risk, and those workers handling the plates were immediately notified.