Asylum seekers staying at a former RAF airfield that is used as the Home Office’s largest mass accommodation site were moved out after safety risks were identified including radiological contamination and unexploded ordnance. Planning permission for the Home Office to use the Wethersfield airfield site in Essex for a three-year period was obtained last month with the granting of a special development order (SDO), circumventing the usual route for obtaining planning permission from a council. But the SDO highlighted a number of concerns about the site, relating to contamination risk from gases, radiological contamination and unexploded ordnance, along with suitable storage for fuel and other hazardous substances and satisfactory arrangements for drinking water. Weeks after the risks were published, it has emerged that 70 asylum seekers are being moved off the site into hotels. The revelation is another blow to the Home Office’s plans to reduce asylum seeker hotel use and provide what it says are cheaper alternatives. A recent report from the National Audit Office found that mass accommodation sites were working out to be more expensive than hotels. The news about Wethersfield follows the disclosure of contamination and unexploded ordnance risks at RAF Scampton in Lincolnshire, another controversial mass accommodation site. The Home Office has scaled back the numbers to be accommodated there from 2,000 to 800. It was expected to open this month but that has reportedly been delayed until June. The home secretary has been ordered to initiate “a programme of intrusive ground investigations to assess contamination” at Wethersfield. The Home Office did not respond to questions about the specific risks identified in the SDO, nor did officials say whether they had produced the required reports about these risks, which are highlighted in the SDO 10 months after the first asylum seekers moved in last July. A Home Office spokesperson said: “We are working to ensure we abide by the conditions.” Graham Butland, the leader of Braintree district council, said the council had written to the Home Office “requesting urgent copies of all the relevant technical documents and plans under the SDO to support our duty in safeguarding the interests of the local community and those living or working on site”. He said the council was awaiting a response from the Home Office. Maddie Harris, the director of Humans for Rights Network, which supports asylum seekers accommodated at Wethersfield, said: “The Home Office continues to put the health and welfare of men at RAF Wethersfield at risk. We have heard from hundreds of men held there, now further supported by the contents of the SDO, that the site is not fit for purpose. Rather than provide safe and secure accommodation, the Home Office insists on pursuing its harmful policy of accommodating men in poor conditions.” The Home Office said: “We have always been clear that the use of asylum hotels is unacceptable, which is why we moved asylum seekers to former military sites which we ensure are safe to accommodate asylum seekers prior to use.”