Approximately 75 CDC staff members potentially exposed to anthrax

The U.S. Centers for Disease Control and Prevention announced on Thursday that approximately 75 members of its Atlanta-based staff have been monitored or provided antibiotics after potentially being exposed to live anthrax.

While the investigation is ongoing, early reports found that the CDC's Roybal campus biosafety level 3 facility tried to prepare anthrax-causing Bacillus anthracis samples for research in other CDC labs at lower biosafety levels. The lab purportedly used a procedure that did not adequately inactivate the samples.

The potentially infectious samples were moved and used for experimentation in laboratories that were not equipped to handle the live pathogen. Workers thought the samples were inactivated and did not wear adequate personal protective equipment when handling the materials. Procedures used in two of the three labs may have also aerosolized the spores.

The unintentional exposure was discovered on June 13 and a review began immediately to assess the health risk. Workers handling the samples were notified immediately, and lab and hallway areas were decontaminated.

Even though potential exposure scenarios found the risk of infection was very low, the CDC took aggressive steps to protect the health of all involved, providing protective courses of antibiotics for potentially exposed staff.

The CDC will internally review why validated procedures were not used by the lab. The CDC will also review the safety protocol again with all employees working with anthrax.