Four days after the Centers for Disease Control and Prevention concluded its investigation into June 's accidental anthrax exposure , more details are being released about the government health agency 's mishandling of potentially dangerous pathogens . The CDC concluded its investigation into the anthrax incident last week , saying that no lab workers had been infected with the disease . But the public health agency 's report also detailed other instances in which lab workers had not followed protocol . The U.S. Department of Agriculture has also been investigating the anthrax incident . In a memo prepared for a congressional hearing this week , the USDA says it had to track down missing anthrax containers and found the infectious bacteria `` stored in unlocked refrigerators in an unregistered hallway '' where workers were freely passing through . USDA inspectors also found that `` select agent materials '' were transferred using Ziploc bags , which do not meet CDC requirements for carrying these materials . The problems date to 2011 , according to the USDA memo . A report from the U.S. Department of Health and Human Services `` found weaknesses in inventory records and expressed concerns about the lack of biosafety and security training for workers with access to these labs . '' In March 2014 , a USDA inspector again expressed concerns about the CDC 's bioterrorism lab , including incomplete inventory records for select agents , such as botulinum and anthrax . The anthrax incident was discovered June 13 . The CDC report says the potential exposure happened between June 6 and June 13 . A lab that had been preparing the anthrax samples for use in two other labs on the CDC 's Atlanta campus `` may not have adequately inactivated the samples . '' That means the other labs were working with samples thought to be harmless ; therefore , workers did n't wear protective equipment they would otherwise have been using when handling such infectious material . Procedures in two of the three labs may have exposed workers to the anthrax , the CDC said . Hallway and lab areas have since been decontaminated . The leader of one of the labs was reassigned shortly after the incident was revealed . CDC spokesman Tom Skinner would not confirm the name of the person who was reassigned . There are three types of anthrax infection : cutaneous ( through the skin ) , inhalation ( through the lungs ) and gastrointestinal ( through digestion ) . According to the report , the exposure happened because the lab that was handling the dangerous material initially did n't use an approved sterilization technique . It did n't have a written plan reviewed by senior staff to make sure all safety protocols were followed , and there was a limited knowledge of peer-reviewed literature about the process that would make it less dangerous . The lab also did not have a standard operating procedure that would make sure the transfer of the material would be safe . Bottom line , `` the scientists failed to follow a scientifically derived and reviewed protocol that would have assured the anthrax was deactivated , '' CDC Director Tom Frieden said Friday . It `` should have happened , and it did n't . '' The lab involved in the anthrax incident will remain closed for such dangerous microbes until Frieden personally approves its reopening under conditions that prevent any such mishap from happening again , Frieden said . The CDC has also stopped moving any biological material out of its two highest-level labs while their procedures are being reevaluated . As a result of these problems , the CDC has created a high-level group of leaders who will work on lab safety issues . It has also started putting together an external advisory group to take a closer look at lab safety . And the CDC is carefully reviewing all the other procedures for labs working with dangerous pathogens , and it has put together a rapid-response command structure to hopefully help the labs avoid future incidents . `` I will say that I 'm just astonished that this could have happened here , '' Frieden said . He stands by his labs , which are considered some of the best in the world , and he stands by his scientists . But he added that he is `` upset '' and `` angry '' and has lost sleep over the incidents , and he is `` working around the clock '' to make sure it never happens again . CDC lab leader reassigned during anthrax investigation .
USDA investigation into anthrax exposure at CDC finds other lab safety problems . The Centers for Disease Control and Prevention has been investigating the 2001 anthrax attacks on U.S. biodefense labs in Fort Detrick, Maryland, since late last year. The CDC director is `` upset '' and `` angry '' that it happened .