Stanlow oil refinery exceeded its permitted toxic pollution limits 58 times across 2023 and 2024, according to Environment Agency documents obtained by investigative journalists. The releases into the air and waterways included cyanide, benzene, and heavy oils, prompting an ongoing regulatory investigation into the Cheshire site.
One of the UK’s biggest oil refineries spilled pollution into local rivers and the Mersey Estuary on dozens of occasions during 2023 and 2024. Documents obtained by investigative journalists from SourceMaterial and shared with broadcasters reveal that the Stanlow oil refinery in Ellesmere Port, Cheshire, repeatedly breached environmental thresholds over the two-year period.
The Stanlow facility is critical to the UK’s fuel supply. It processes approximately 10 million tonnes of crude oil annually and produces about 18% of the country’s fuel for road transport like cars and trucks. Operated by EET Fuels—formerly known as Essar—the refinery holds an environmental permit allowing it to discharge controlled amounts of oil and chemicals into the air and waterways while requiring efforts to limit pollution and harm to humans.
The 58 Permit Breaches and Chemical Releases at Stanlow
Environment Agency (EA) reports into activities at the refinery show that permitted levels for chemical releases were exceeded hundreds of times in 2023 and 2024. The regulator determined that EET Fuels broke its permit conditions 58 times over the two years.
The unsealed documentation details specific releases into the air and waterways.
In July 2023, a significant breach occurred when rainwater containing oil leaked from the site and contaminated groundwater supplies.
A subsequent incident took place in September 2024, when another EA report documented an oil spill. More than a tonne of oil was released into Thornton Brook and spread to the Mersey Estuary.
Impact on the Mersey Estuary and Local Fisheries
The pollutants travelled into local waterways including Thornton Brook and the River Gowy, which connect to the Mersey Estuary. The estuary holds status as a Site of Special Scientific Interest (SSSI) and serves as a vital habitat for endangered species and a breeding ground for rare birds.
Local cockle beds in the estuary were closed following the 2024 spill.
Taylor noted the economic repercussions for local fishers due to the closure of cockle beds following the 2024 spill.
Company Invests £24 Million to Improve Compliance Ratings
The company also stated that it has backed its environmental commitments with decisive action, investing over £24 million in major wastewater infrastructure alone and delivering a measurable, upward trend in Environment Agency compliance ratings, improving from an F rating in 2023 to an E rating in 2024 as major capital projects came online.
