for disease control and prevention in atlanta. analysts say this could be the largest case of anthrax exposure in more than a decade. but agency officials say the risk of infection is quite low. the cdc reports workers at a high-level biosecurity lab in atlanta did not kill the bacteria before sending the samples to a lower security lab. it was not equipped to hasn't live anthrax. the cdcs deputy director tells john roberts in atlanta that the incident is incredibly troubling. >> we are very, very concerned about this happening, and we're very, very committed to ensuring it does not happen again. >> agency officials say they're still monitoring staffers and giving them antibiotics. we have the president of the national foundation for infectious diseases and a member of the cdc advisory committee. good to see you. big deal here? concerning? >> sure, it's concerning, and must be terribly disheartening