The United States military sent a sample of potentially live anthrax to a lab in the UK.
The Health and Safety Executive (HSE) said it is "aware" the lab, which has not been named but is believed to be run by a commercial company, received the sample in 2007.
No one at the firm fell ill or showed any symptoms of being exposed to the deadly bacteria, the HSE said.
The US Department of Defence has been in touch with the firm, which destroyed samples after testing.
It has inadvertently sent possibly live samples of the bacteria to dozens of labs across the United States and other countries.
In a statement HSE said: "Relevant government agencies are aware of this historical issue and the US Department of Defence (DoD) has been in touch with the company.
"The samples were sent from DoD to the company in 2007 and the company has informed us it destroyed samples shortly after testing.
"On this basis we do not believe there is any continuing health risk to staff or to the public.
"If anyone would have been exposed in 2007, symptoms would have presented shortly after. No such reports of ill health were apparent in the workforce."
The statement said the HSE and the Government will support the firm if necessary and will talk to the US to "ensure similar situations are avoided in the future".
Anthrax is a potentially deadly disease that normally affects animals.
Those who become infected by it by breathing in anthrax spores display flu-like symptoms before coming down with pneumonia and often fatal respiratory collapse.
If it gets into cuts it can cause blood poisoning.