Production at a vaccine site in Wales had to be stopped for hours while police and Army investigated a suspect package.
All staff were evacuated from the Wockhardt site, which employs around 400 people, in Wrexham.
The global pharmaceutical and biotechnology company provides fill-and-finish services for the Oxford/AstraZeneca Covid-19 vaccine – the final stage of putting the vaccine into vials.
A spokeswoman insisted the production schedule was not affected.
Police officers and a bomb disposal unit were called to the scene mid-morning on Wednesday.
North Wales Police said a team from the Royal Logistics Corp “attended and examined the package to make sure it was safe to handle” adding that the contents would be taken away for analysis and an investigation would continue into the circumstances surrounding the incident.
Shortly before 5pm, a Wockhardt spokeswoman said that while manufacturing had been “temporarily paused”, staff were being allowed back into the facility after the package was “made safe”.
She added: “This temporary suspension of manufacturing has in no way affected our production schedule and we are grateful to the authorities and experts for their swift response and resolution of the incident.”
She said she could not give information on quantities of vaccine on site but that production “had been proceeding at pace to meet the Government contract for 100 million vaccine doses”.
Welsh First Minister Mark Drakeford tweeted to thank “the security personnel who are on-site to protect lives and ensure the safety of our vaccine supply”.
Last week, emergency teams were called out to protect vaccine supplies following flooding at the industrial estate.
All “necessary precautions” were taken to prevent disruption to the manufacture of the jab, a Wockhardt spokeswoman said at the time.