ReAwaken America tour attendee said of one person who had become sick: "He has all the signs of some sort of anthrax or derivative."
"It is a conservation disaster—but it also has the potential to be a public health crisis," said conservationist Niall McCann.
Researchers have detected novel viruses in samples of glacial ice, suggesting global heating could lead to the re-emergence of historic pathogens. But the science is uncertain.
Two doses of the vaccine protected mice, rats and rabbits against inhalational anthrax and pneumonic plague.
Musicians from Black Sabbath, Kiss, Blink 182, Megadeth, Anthrax and others honored the ex-Pantera drummer.
The substance contained in the letter has been tested and has been found to be harmless.
The discovery raises concerns over North Korea's biological weapons production.
The algorithm they created can analyze if bacterial spores are anthrax in less than a second.
The lab at Dugway Proving Ground, an Army facility near Salt Lake City, is responsible for neutralizing anthrax spores.
A military facility inadvertently sent the live bacteria to nearly 200 research centers in the U.S. and beyond.
The Pentagon said there was no known suspected infection or risk to the public.
The technician was working on Monday with Ebola specimens that were supposed to have been inactivated but which may instead have contained live virus.
A recent congressional hearing laid bare numerous safety problems within the U.S.'s federal laboratories.