Two defense officials today confirmed that in addition to accidentally sending live samples of anthrax to 28 government and private facilities across the US and army base in South Korea, the Pentagon also shipped the deadly spores to three laboratories in Canada. Investigations into anthrax shipments spurred by the recent discovery of the spores have shown that the US military also sent live samples to Australia in 2008, meaning that suspected live anthrax has now been sent by the Pentagon into three countries, 12 US states, and the District of Columbia.

The anthrax, which was sent from an Army lab at Dugway Proving Ground in Utah, was supposed to have been rendered inactive by Department of Defense scientists before being shipped for research purposes. A senior Defense Department official told USA Today that so far, no-one has been confirmed as infected by the still-alive samples, but BBC News reports that at least four US civilians and 22 military personnel from South Korea's Osan air base are receiving preventative treatment.

In an email sent on Friday and obtained by USA Today, Daniel Sosin, deputy director of CDC's Office of Public Health Preparedness and Response, suggested that the Dugway Proving Grounds base's methods of killing anthrax spores was not entirely effective. "We have concern that the inactivation procedures, when followed properly, are inadequate to kill all spores," Sosin said, but noted that "the US government is developing an approach to securing such possible samples from misuse."