Stanlow Refinery Repeatedly Exceeded Toxic Pollution Limits, Leaked Documents Reveal

One of Britain's largest oil refineries has been responsible for dozens of breaches of its environmental permit over a two-year period, according to internal documents obtained by investigative journalists and shared exclusively with the BBC. The records suggest that EET Fuels, the company operating the Stanlow refinery in Ellesmere Port, Cheshire, released harmful substances into local waterways, groundwater, and the air on numerous occasions during 2023 and 2024.

Stanlow is the second-largest refinery in the UK and one of just four still operating in the country. It processes approximately 10 million tonnes of crude oil annually, supplying roughly 18% of the nation's fuel for road transport, including cars and trucks. EET Fuels, which purchased the site from Shell in 2011 for £842 million, holds a permit allowing it to discharge controlled quantities of oil and chemicals into the environment. However, the company is legally required to minimise pollution and any resulting harm to human health.

The documents, uncovered by environmental journalists at SourceMaterial, indicate that permitted chemical release levels were exceeded hundreds of times across 2023 and 2024. The Environment Agency (EA), which regulates the site, concluded that EET Fuels breached its permit conditions on 58 separate occasions during that period, each of which could constitute an illegal offence. The EA has confirmed it is investigating the breaches.

Among the pollutants detailed in the reports are toxic substances such as cyanide, benzene, and heavy oils. These were released into the air and into local waterways including Thornton Brook and the River Gowy, both of which flow into the Mersey Estuary. According to the EA documents, sulphur dioxide was emitted into the air at levels seven times higher than permitted, cyanide entered waterways at more than eight times the allowed concentration, and oil was discharged at over thirteen times the permitted level.

The Mersey Estuary is designated a Site of Special Scientific Interest (SSSI) and provides critical habitat for endangered species, including dolphins, as well as a breeding ground for rare birds. Charlotte Harris, chief executive of Cheshire Wildlife Trust, emphasised the ecological importance of the area, noting that species such as dunlin, black-tailed godwit, and redshank travel from around the world to feed and roost on the land surrounding the river.

Harris explained that this biodiversity has only been made possible through years of pollution cleanup efforts by organisations including the Wildlife Trusts, addressing contamination left by earlier industry in the region. She also highlighted the return of Atlantic salmon to the river and the annual migration of the critically endangered European eel up the Mersey and into the River Gowy to breed. The Mersey Estuary is home to the largest population of protected dunlin in the UK.

One particularly serious incident occurred in July 2023, when rainwater contaminated with oil escaped from the Stanlow site. The EA classified the event as "significant." Its report noted a substantial number of complaints from local residents about odours, and subsequent investigations found that oil had contaminated groundwater supplies. In response, EET Fuels told the BBC that the quantity of oil lost was on a "low scale" and was "strictly localised to two boreholes, all well within the Stanlow site itself."

A second major spill took place on 12 September 2024, when oil was again released from the facility. Over a 36-hour period, more than a tonne of oil flowed into Thornton Brook and eventually reached the Mersey Estuary. Although EET Fuels reported the incident to authorities, it took nearly two weeks for the company to provide an estimate of the volume spilled. This delay constituted a further regulatory breach, as permits require such estimates to be submitted within 24 hours.

An emergency response was subsequently organised, involving the EA, Natural England, local port authorities, and the Fisheries Authority, according to meeting records. Natural England, which oversees SSSIs, warned during one meeting that the pollution would likely impact vegetation and salt marsh in the area, and that there remained a probable risk of birds ingesting the oil.

A drone survey was deployed to assess the extent of the damage. It revealed that oil had spread more than a mile downstream and that "brown discolouration" was visible around the reedbed. The footage also captured wading birds, including the red-listed dunlin, in the affected area. Harris stressed that chemical pollution in such environments is not confined to a single location. Because river systems are highly dynamic and energetic, contaminants can spread rapidly and over great distances.

The revelations come after EET Fuels pleaded guilty earlier this year to 12 charges of breaching environmental law between 2018 and 2020. The newly obtained documents suggest a pattern of regulatory non-compliance that extends well beyond that period. EET Fuels has stated that it "takes its environmental responsibilities extremely seriously," but the EA's findings raise questions about the adequacy of oversight and the frequency of pollution incidents at the site.

The Environment Agency's investigation into the 2023 and 2024 breaches remains ongoing. The outcome could have significant implications for EET Fuels, the future of the Stanlow refinery, and the fragile ecosystems of the Mersey Estuary that depend on strict environmental protections.