Asylum seekers are at a “high risk” from contact with hazardous material, some of it radioactive, at a former military base being used to house them, a report has found.
Another study into the Wethersfield site also found nuclear and chemical weapons, including mustard gas, may once have been stored there when it was used by the US Air Force.
The government wants to move 1,700 migrants into the site in the Essex countryside but residents living nearby, who are opposed to the plans, have highlighted contamination of the former airfield.
About 40 asylum seekers, who are believed to have arrived in the UK after crossing the English Channel in small boats, are the first occupants.
The camp was originally known as RAF Wethersfield and was first used during the Second World War before being taken over by the US Air Force during the Cold War.
A report commissioned by the local parish council, as well as other government studies, has highlighted the legacy of contamination.
One study by engineering consultancy Buro Happold was commissioned by the parish council’s Wethersfield Airbase Scrutiny Committee.
Its chairman Andrew Hull, who is a resident fighting the plans, told The National that reports into the site reveal a “frankly terrifying list of potential contaminants”.
Buro Happold said the risks associated with the site from “Hazard Class 1” materials include radioactivity, aircraft and vehicle fuel, asbestos, firefighting foam and demolition material.
For any “future site users/visitors” who may come into direct contact with the materials, ingest them or inhale dust containing them, there is a “high risk”, says the report.
There is also a “moderate” risk from explosives and ordnance to those two groups at the site.
It recommends the ground is examined by specialists, including those in radioactivity and explosives, with chemical analysis carried out and a decontamination plan put in place.
Opponents have also obtained two other reports into the site under freedom of information rules, one from the Defence Infrastructure Organisation (DIO) and another from Homes England, the government’s housing and regeneration agency.
The 248-page DIO study says there is “anecdotal evidence” that the US Air Force may have stored nuclear and chemical weapons including mustard gas at the site.
It also suggests the presence of potential contamination from radioactivity, explosives, fuel, asbestos, hazardous chemicals and waste storage.
Homes England warned of a contamination risk when it investigated the site for a “garden community”.
“The Wethersfield site will undoubtedly contain residual contamination in various areas of the site as there are no signs of any significant demolition and remediation having been carried out,” said its report.
Pictures shot from a drone show work being undertaken to ready the site for more arrivals, with a crane lifting cabins into place.
Mr Hull said “to even contemplate building, or housing people, on such land, seems beyond reckless to human life” but “neither the Home Office nor the Ministry of Justice are listening to warnings”.
“The Buro Happold report, which we as 13 parish councils commissioned, was written by a highly regarded expert on land contamination,” he said.
“Many Class 1 hazards have been identified on the site, which could lead to a high risk of severe consequences to human health, as the site currently stands. Visitors, staff and residents are all being put through high risk.”
Alan MacKenzie, chairman of residents’ group The Fields Association, said the findings meant “it is fundamentally dangerous to have anybody at the site until it has been properly investigated”.
He said the report had been presented to the Home Office but “we’ve had nothing back from them at all and they’ve not responded to any questions provided”.
“They’ve been handed a report from an international organisation but they’re doing nothing about it,” he added.
British Prime Minister Rishi Sunak has made stopping small boats ferrying migrants across the Channel one of his government's key pledges.
About 12,000 have made the journey so far this year, while last year the total exceeded 45,000. Huge tents have also been bought to house migrants to avoid the more expensive option of keeping them in hotels.
A UK government representative said: “Delivering accommodation on surplus military sites will provide cheaper and more orderly, suitable accommodation for those arriving in small boats while helping to reduce the use of hotels.
“These accommodation sites will house asylum seekers in basic, safe and secure accommodation as they await a decision on their claim. The safety of individuals in our care is always our absolute priority.”