An entire ambulance base, including a helicopter, is undergoing tests as part of a murder probe after two people were poisoned with Novichok in Amesbury.
Wiltshire Police said “highly precautionary” testing would be carried at the Wiltshire Air Ambulance station on Wednesday in which all emergency vehicles, including the air ambulance, would be examined for traces of the nerve agent.
Kit worn by paramedics who came to the aid of Charlie Rowley and Dawn Sturgess when they were poisoned in June will also be examined.
The tests are being done, police said, to ensure that “no onward contamination has taken place”.
Rowley and Sturgess were exposed to the nerve agent in Rowley’s home on June 30. Sturgess, 44, died in hospital eight days later, sparking a murder investigation.
Rowley last month told how he believed a cosmetic bottle he found and later gifted to his girlfriend contained the nerve agent that was also used in the attempted murder of former Russian spy Sergei Skripal and his daughter Yulia in Salisbury on March 4.
The UK government has blamed Russia for the attack.
Wiltshire Police said the testing was being done because it was “essential that no chances are taken”.
As a result, the ambulance base, located in Semington, was closed temporarily from 5pm on Wednesday and the air ambulance was grounded.
The charity’s paramedics and doctors would remain fully operational, providing critical care in Wiltshire by using Rapid Response Cars, the ambulance service said.
The cars have the same specialist medical equipment that is onboard the helicopter.
“It is important to again stress that the testing forms part of the wider response to the incident and is being undertaken on a precautionary basis,” Wiltshire Police said, reiterating that the advice from Public Health England had not changed since the police investigation was first launched.
“The risk to the public and first responders remains low. It has, therefore, not been necessary to shut this site before,” the force added, and said once the testing is compete, a decision will be made on whether any “wider remediation work needs to take place”.
Deputy Chief Constable Paul Mills, who is leading the multi-agency response to the incident, admitted the testing “might cause some concern to our communities”, but said it was necessary to “further reduce any residual risk”.
Police and Crime Commissioner Angus Macpherson added: “All agencies are working closely together and are working incredibly hard to ensure the safety of staff and of course of the public.
“Its right that action is taken to rigorously and thoroughly test where the scientific advice dictates its appropriate to do so. Public safety must remain the number one priority and I am confident this is at the absolute forefront of any action taken.”