The Pentagon said on Wednesday a United States military facility in Utah has mistakenly sent live anthrax bacteria to private laboratories in nine different US states and also a US military base in South Korea.
There was no risk to the public or no known suspected infection, said the Pentagon, adding four civilians have been started on preventive measures, including vaccine, antibiotics, or both.
The US Centers for Disease Control and Prevention (CDC) has announced it has launched an investigation on the case, calming public that the four faced minimal risk.
The CDC spokesman Jason McDonald said the four were "doing procedures that sent the agent into the air."
Anthrax can cause a deadly illness when it becomes airborne, called inhalation anthrax, which killed five people in the US in 2001, after being sent to government and media targets through mails.
"All samples involved in the investigation will be securely transferred to CDC" or affiliated labs for further testing," said another CDC spokesperson Kathy Harden.
The Pentagon said the sample sent to South Korea was destroyed.
The incident was revealed when the Maryland laboratory alerted the CDC having a live sample on Saturday.