A quarry operator blamed for a foul stench affecting people living in Darlington and County Durham has said recent tests did not raise any concerns. 

Ashcourt, which owns the quarry near Newton Aycliffe, said it has invested heavily to stop the smell, described as like “rotten eggs” by residents. 

Officers from the Environment Agency attended the quarry on Thursday (July 18) to test for gas emissions, the quarry operator said.

“It is fair to say that this did not raise any concerns which would mirror the type of odours which are being complained about,” a spokesperson added. 

Instead, Ashcourt claimed the Environment Agency carried out tests of other businesses in the area, adding: “We are aware that there are odours emanating from different businesses in the local area and believe that the Environment Agency is conducting enquiries.”

The Local Democracy Reporting Service understands officers tested for methane and any issues were remediated on the day. 

Gary Wallace, Area Environment Manager in the North East, said: “We understand how unpleasant the odour issues are for the community and we’re committed to ensuring the operator takes the necessary action to control the gas emissions from the site."

An investigation into the stench is ongoing after the authority issued an enforcement notice in February. A fixed odour monitoring unit has also been installed in Brafferton, a nearby village where residents have reported the smell. 

But frustrated residents have called on Darlington Borough Council to push for quicker action. 

Alex Swainston said: “Ashcourt in Darlington has been continuing to poison the air and affecting residents' physical and mental health with the toxic gas leaks of methane and hydrogen sulphide for nearly a year.”

Ashcourt said it has updated the gas infrastructure and capped a large section of the landfill since taking over the site in May 2023. 

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A spokesperson said: “This involves putting right the problems which had been identified back in 2021 by the Environment Agency, but which had not been fully resolved by the previous owners. To achieve this we are investing very heavily into the site.   

Initial findings from the odour monitoring unit are due to be revealed soon. 

Mr Wallace, from the Environment Agency, added: “We continue to assess the site regularly and an investigation into any breaches of the site’s environmental permit is ongoing.”