DECONTAMINATING a mobile home park at Eynesbury, which is permanent home to 50 households, is likely to cost about \u00A31,334,000, Huntingdonshire District Council's cabinet will be told tomorrow (Thursday). That compares with around \u00A3500,000 estimated just six months ago before the cost of the decontamination work was included in the overall total (the original estimate was predominately the cost of providing temporary accommodation for residents). But Council Tax payers will stump up only \u00A335,000, the cost of the original investigation of the site that discovered the problem, and some re-planting. Soil under 46 of the homes is contaminated by a chemical that could possibly cause cancer if someone were exposed to it over a whole lifetime. HDC stresses there is no short term risk, but it is required by law to remove the affected soil and replace it with uncontaminated material. Families will be moved out in turn while two feet of soil is dug out and removed. This means the council is having to buy up to five mobile homes - at \u00A380,000 each - to house the families for the two weeks it will take for the work to be done on each pitch. No decision has been taken on where they will be sited, but some are likely to be on the site itself to minimise disruption for residents. With conveyancing and other costs, including the work itself, currently out to tender, the total bill is expected to exceed \u00A31.33million. But, when the mobile homes have been re-sold and the Government has paid for nearly all the other work, including the detailed scientific investigation and excavation, the burden on Council Tax payers is expected to be small - though they will have to pay a horticulturist to re-plant people's gardens. Remedial work should start early next year and take about six months. The site, off Howitts Lane, was built on 17th-19th century clay pits that were found during a routine check to have been filled in with pulverised fuel ash from commercial furnaces during or after the Second World War. When test borings last year found concentrations of benzo (alpha) pyrene at 10-times the national background level of one part per million, HDC warned residents to take particular care with personal hygiene and not to dig deep holes in the soil. High concentrations of carbon dioxide - a breakdown product of benzo(alpha)pyrene - were also found in areas where residents had put brick bases beneath their caravans. Sue Lammin, HDC's head of environmental services, said then: "No level of benzo(alpha)pyrene has been identified as safe. It has not been shown to cause cancer in humans, but it has in animals at high levels. There's a theoretical risk if people spend a lifetime there. It is right that we should be cautious." The possibility of watercourse contamination was ruled out, because any leachate would be contained by the clay.