The Pentagon recently revealed that the number of laboratories that received shipments of live anthrax samples increased to 68, including one lab in United Kingdom.

A statement from the UK Health and Safety Executive stated that the company has informed them that it destroyed the samples of the deadly bacteria shortly after testing.

"If anyone would have been exposed in 2007, symptoms would have presented shortly after. No such reports of ill health were apparent in workforce. On this basis we do not believe there is any continuing health risk to staff or to public", it said.

It has been said that the samples were sourced from Dugway Proving Grounds, a top government bioweapons facility in Utah, which distributed them for research purposes, to a facility operated by UK staff.

Experts said that the anthrax sent for research purpose needed to be 'inactivated' in order to prevent possible contagion, and stop agent who could use it as a biological weapon from obtaining it.

The UK said in statement that they are looking forward to have a talk with the US Department of Defense to understand how this issue arose in 2007 and how they will ensure similar situations are avoided in the future.

The crisis began last month, after a lab reported working on a bioweapons test said that it was able to accidentally grow anthrax after receiving a supposedly inactive culture.

The Pentagon then decided to retest 400 batches, out of which at least four contained live bacteria.

DoD Colonel Steve Warren about the latest results said that another batch was tested positive and that lot had sent samples to the UK and Massachusetts.

According to its latest statistics, the improperly treated samples were sent to 19 US states and four foreign countries, including Canada, South Korea and Australia.