Prime Minister Theresa May has assured visitors and residents that "Salisbury is safe" as the decontamination of nine Novichok hotspots around the city begins.
A number of new barriers appeared at various locations in the city last week as officials launched what is expected to be a several months-long clean-up operation.
Mrs May, responding to a question from former defence minister Dr Andrew Murrison at Prime Minister's Questions, told MPs that residents had no need to take any additional precautions.
Dr Murrison (South West Wiltshire) said: "At Thursday's recovery meeting in Salisbury the public was told that nine Novichok hotspots remain in the city and around the city and that the clean-up may take until the end of the year.
"In thanking the Prime Minister for her very close interest in this matter canI ask what more can be done to expedite the clean-up so that life in SouthWiltshire can return to normal as soon as possible?"
Mrs May said: "Can I make it absolutely clear that Public Health England have said Salisbury is safe for residents and visitors, there's no need for anyone to take any additional precautions.
The nerve agent Novichok is believed to have been used in liquid form to target Sergei and Yulia Skripal last month.
Former Russian double agent Sergei Skripal and his daughter Yulia were found unconscious on a bench in the Wiltshire city on March 4.
The Government has said a military-grade Novichok nerve agent of a type developed by Russia was used in the attack, although Moscow denies any involvement.