Some emergency service vehicles used in the response to novichok poisonings in Wiltshire have been buried in a landfill site.
The secure burials would pose “absolutely no risk to the public”, a spokesman for the Department for Environment, Food and Rural Affairs said.
Defra did not disclose the number of vehicles nor the emergency services that had used them but confirmed that some had been sealed in a hazardous waste landfill site near Bishop’s Cleeve in Gloucestershire.
The UK government has blamed Russia for the nerve agent attack on the former spy Sergei Skripal and his daughter, Yulia, in Salisbury in March.
In July, Dawn Sturgess died after becoming an indirect casualty of the poisoning. Authorities believe she and her boyfriend, Charlie Rowley, picked up a discarded vial containing the substance.
A Defra spokesman said: “The cleanup work in south Wiltshire has been under way for some time and any potentially contaminated items continue to be removed and stored securely before being disposed of safely.
“As part of this work, following review by specialist teams, some of the vehicles involved in the response to the incident in March have been moved to a hazardous waste landfill site.
“There is absolutely no risk to the public of using hazardous waste landfill sites. These locations are fully sealed and highly regulated to ensure waste is disposed of safely. This is controlled by regulation, overseen by the Environment Agency, which specifically ensures that sites are not prone to flooding or other hazards.
“Our number-one priority is making sure that the identified sites are safe, so they can be returned to use and Wiltshire can get back to normal.”
The novichok attacks caused an international diplomatic incident, with the home secretary, Sajid Javid, accusing the Russian state of using Britain as a “dumping ground for poison”.
Kremlin spokesman Dmitry Peskov previously said linking Russia to the poisoning would be absurd.