Citing an anthrax scare and other safety concerns, the Centers for Disease Control and Prevention has temporarily shut down two of its laboratories.

The announcement on Friday follows incidents in the past month that involved the possible exposure of dozens of lab workers to anthrax at facilities in Atlanta.

In the second such incident, NPR's Richard Harris reports that "In the course of trying to understand a laboratory accident involving anthrax, officials at the Centers for Disease Control and Prevention stumbled upon another major blunder — involving a deadly flu virus."

The Associated Press reports:

"The CDC also released a report that detailed three other incidents in the past decade in which mistakes or other problems caused potentially dangerous germs to be sent out. No lab worker or member of the public was sickened in any of the incidents, the CDC said."The federal agency operates some of the world's most advanced and most secure laboratories for the handling of deadly germs, and has enjoyed a reputation as a role model for that kind of work. During a press conference Friday, CDC director Dr. Tom Frieden said he was upset by the carelessness."'I'm just astonished that this could have happened here,' he said."Frieden said internal and outside panels will investigate both recent problems and review safety procedures for handling dangerous germs."

The Washington Post says:

"Federal government laboratories in Atlanta improperly sent potentially deadly pathogens, including anthrax, botulism bacteria and a virulent bird flu virus, to other laboratories in five separate incidents over the past decade, officials said Friday.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.