The Department of Defense says that the Army's Dugway Proving Ground in Utah failed to completely kill samples of anthrax in May before it shipped them to dozens of other labs around the world.
NPR's Geoff Brumfiel reports that the samples of anthrax the Pentagon thought were dead, were still alive:
"It appears Dugway's procedures for killing anthrax weren't effective. Neither were its tests to make sure the spores were dead. Despite these problems, individual shipments contained very little live anthrax. And to date, [Deputy Defense Secretary Robert Work] says nobody's gotten sick."
The Pentagon says the public was never at risk.
Geoff says the lab wasn't breaking any rules, but the procedure they used allowed them to overload the machine they used to kill anthrax with the samples. It's like overloading your dryer – if you put too much in, you'll end up with some wet clothes.
According to the DOD website, 86 labs and 21 personnel are being monitored and receiving post-exposure prophylaxis. Seven foreign countries (Japan, the U.K., Korea, Australia, Canada, Italy and Germany), and 20 U.S. states and the District of Columbia are also being monitored.
Geoff reports that tests with anthrax are usually conducted with dead samples, and that's what the DOD thought were shipped. He says, "Anthrax are highly infectious bacteria that can travel through the air and infect people."
You can read more about the anthrax shipments here.