A HOUSING developer in Wiltshire, southern England faces a large bill for disposing of naturally occurring clay because the Environment Agency says it is contaminated waste.
Kimmeridge Clay with high levels of calcium sulphate (gypsum) is being removed from the site of a Persimmon Homes housing development at Churchwood, Swindon.
The Agency has classified the clay as contaminated waste because sulphate levels exceed allowable thresholds. Persimmon has been ordered to dispose of it in a sealed landfill site, forcing its subcontractors to pay thousands of pounds in landfill tax.
Mike Fletcher, the Agency's Thames Regional waste manager, said it was feared sulphates would leach into surrounding ground once the material had been disposed of.
But independent consultant Julian Parry, working for one of Persimmon's subcontractors, disputed the ruling, saying sulphates cause no harm to humans or animals. He claimed calcium sulphate was non-soluble so the risk of leachates contaminating surrounding ground was almost nil.
Parry said the material should be classified as inert waste, exempting it from the landfill tax and making it suitable for use in landscape restoration at the local Peat Moor site.
He argued that the Agency's thresholds for measuring contamination were based on criteria drawn up to assess industrial pollution from gasworks. They did not relate to naturally occurring chemicals, he said.
The Agency was also ignoring the fact that the Peat Moor disposal site was founded on similar Kimmeridge Clay, Parry added.
Parry warned the ruling would set a precedent for the countless sites across the country where there are high naturally occurring chemical concentrations.
Experts in environmental law described the Agency's approach at the Churchwood site as 'exceedingly cautious but difficult to fault'.
Kathy Mylrea, a partner at lawyer Simmons & Simmons, said there were huge cost implications for developers and companies undertaking large-scale site restorations - for example on quarry, mining or landfill sites - who would find it harder to source fill material.