Emissions under-reported at Silverdale Walley's Quarry

A 'calibration' problem had led to an under-reporting of hydrogen sulphide, said the Environment Agency

Levels of noxious gas emissions at a smelly landfill site have been under reported by the body checking them.

Walley's Quarry in Staffordshire has for years been the subject of thousands of complaints over odours, which some residents fear pose a health risk.

Nasty gas hydrogen sulphide, which smells like rotten eggs, was found to have sometimes exceeded limits there.

But the Environment Agency (EA), which monitored levels and since reported reductions, has admitted data flaws.

In 2021, a council served a statutory nuisance abatement notice on the quarry which committed to cutting emissions, with the EA reporting the following year an overall trend of hydrogen sulphide reduction.

On Thursday, however, the EA said the publishing of figures pertaining to the quarry had been suspended after the problems with records emerged. It is so far unclear for how long a period the data was erroneous.

The EA issued an apology to the community of Silverdale and said people would be "disappointed and concerned" by the news.

The company running the site, Walleys Quarry Limited (WQL), said it was "disappointed" by the development.

An MP has accused the EA of "letting down" residents and "denting public confidence".

Thousands of complaints have been made about the smell from the landfill in Silverdale

Staffordshire County Council said the figures could not be relied upon to assess the risk to people's health.

In a joint statement with the UK Health Security Agency and the Staffordshire and Stoke-on-Trent Integrated Care Board, the authority said the risk of long-term health problems was small "but cannot be excluded at this stage".

Up to 400,000 tonnes of waste is dumped annually in Walley's Quarry and, when it breaks down, can produce hydrogen sulphide.

People in Silverdale have long demanded more stringent action.

Last month, Walleys Quarry Ltd (WQL) was ordered to improve the capping of waste at the site.

It followed an unannounced EA inspection in June which found temporary clay capping was inadequate.

An inspection in June found part of temporary clay capping to be inadequate

The EA shares data on the presence of hydrogen sulphide and also methane on a weekly and monthly basis.

It said it had temporarily paused publishing figures on hydrogen sulphide due to a calibration problem.

The scale of the under-reporting would "vary over time", it said, and it was seeking further advice to check whether it was possible to "reliably adjust" historical data to correct the issue.

"Our immediate focus is on working with partners so together we can give the best information, advice and support to the community as quickly as possible," the EA explained.

WQL said: "We will await further information from them to allow us to better understand the full implications of this development."

Local MP, Aaron Bell, who has previously raised concerns about the site, said the community had been "badly let down".

Results from a previous monitoring exercise between 2017 and 2019 were "also clearly now incorrect", the Conservative MP for Newcastle-under-Lyme claimed.

"Given that the EA relied on these results to justify to me why they would not install more monitoring - before eventually realising the stink was so bad they would have to - the community was particularly badly let down in this regard."

He said the error had "dented public confidence" in the agency and he would be raising the issue in the House of Commons.

A virtual public meeting is to be held on 9 October at 19:00 BST, the EA said.