A US military laboratory based in Utah is under investigation after mistakenly sending live anthrax bacteria to nine commercial labs and an air base in South Korea.
The shipments which were part of a military research project continued for a full year before the error was noticed.
The US Centers for Disease Control and Prevention claims no one was at risk although four people have been started on preventative measures.
When anthrax becomes airborne, it can cause a deadly illness.That occurred in 2001, when anthrax sent through the US mail to government and media targets killed five people.
The mishap comes 11 months after scores of CDC employees were potentially exposed to live anthrax spores when the Center similarly mishandled samples..