More than100 old landfills across England containing potentially hazardous material have flooded at least once this century, according to analysis by Unearthed.

Historic landfills can contain dangerous substances such as heavy metals, persistent pollutants, pharmaceuticals and industrial waste. They often lack measures such as linings that limit the risks of these pollutants affecting the surrounding environment. 

Unearthed also found over 2,600 former dump sites with potentially hazardous contents within 50m of watercourses across England. 

Most of the 20,000-odd former landfill sites are likely to be quite safe… but some could be quite sinister

– Dr David Megson

As climate change threatens to make floods more frequent in Britain the risk of landfills leaching substances into watercourses goes up, scientists warn.

“We’ve been landfilling waste for hundreds of years, but we haven’t really considered the consequences of climate change on those historic landfills and the pollution they contain,” Professor Kate Spencer, an expert on historic landfills at Queen Mary University of London, told Unearthed.  

“We now know far more about the potentially harmful effects of the waste materials and pollutants we’ve dumped, particularly chemicals like PFAS and PCBs, and how the impacts of climate change, such as flooding, could reopen pathways for those pollutants to enter the environment,” she added. 

PFAS (per- and polyfluoroalkyl substances)are a group of thousands of man-made chemicals that are widely used in consumer products to make them heat resistant, non-stick or stain-repellant. Exposure to some of these chemicals has beenassociated with cancersand health complaints, including liver disease and decreased fertility. PCBs (Polychlorinated Biphenyls) are man-made organic chemicals that were used in a variety of industrial processes, often for their flame-retardant properties. They have been phased out globally starting in the 1970s, with strict controls on their production and disposal, partly due to their links with cancer. They are among the substances known as “forever chemicals” because they take hundreds or even thousands of years to break down in the environment, meaning that even if they were dumped decades ago, they could still pose a risk to those who are exposed to them now. 

There are almost 20,000 historic landfill sites across the country, but records of what these sites contain are patchy. There is no central record of whether former landfills have been officially designated as contaminated sites, as this happens at local authority level but scientists believe they could contain hidden dangers. 

“Most of the 20,000-odd former landfill sites are likely to be quite safe and contain relatively inert waste, but some could be quite sinister,” Dr David Megson, a scientist at Manchester Metropolitan University who previously worked remediating old landfills, told Unearthed. “Historic reporting of what went into these sites wasn’t great, so in many cases, you’ve got little idea what is in there until you dig into it.”

Unearthed, working with Dr Paul Brindley at the University of Sheffield, overlaid Environment Agency (EA) flooding data onto the government’s map of historic landfillsacross England to identify sites that have flooded since the turn of the century.

Using the government’s dataset, Unearthed identified landfills that had closed before rules came into force in the mid-1990s to protect the environment from pollution, and those which had had at least half of their surface area flooded. We removed any landfills that have been built on or otherwise concreted over. Within this subset, Unearthed looked for landfills marked as taking potentially harmful waste, including “commercial” and “industrial”, as well as “special” waste, which requires special disposal requirements due to its potential to pollute and “liquid sludge”, which comes from industrial processes. 

The EA’s data does not record every flood event, while the historic landfills database only contains a partial record of what went into these former dump sites.Only 55% of sites in the historic landfills dataset record a “last input” date, showing when they stopped receiving waste. Owing to the patchy nature of both datasets, Unearthed’s figures are likely to be an underestimate.

Sites across the country

Historic landfills are dotted all over the country, but most people would have no idea they live near one. There are many public parks and nature reserves built on old landfills, and Unearthed identified instances where business parks and housing estates were built directly alongside or even overlapping former landfills with potentially hazardous contents that had flooded this century. 

The Green party, along with councils including Brighton & Hove, have backed ‘Zane’s law’, which aims to update the UK’s rules on toxic waste disposal. The law is named after Zane Gbangbola, a Surreyseven-year-old who died in 2014. His family believe his death was caused by toxic chemicals that entered their home when a nearby disused landfill flooded. 

Gbangbola’s family said that no environmental searches on their property had identified that the lake behind it was a former landfill site – this information only came to light after their son had died. Lavenders, the former landfill site, is not included in Unearthed’s analysis, as the historic landfills database does not record the types of waste it received or the date it closed.

Zane’s law would impose a dutyon councils to record potentially contaminated sites, and to investigate and, where necessary, remediate former landfill sites. It would also make central government responsible for covering the cost of these works.

Green party peerNatalie Bennett told Unearthed: “The lack of adequate regulations on contaminated land poses a threat to human life and welfare, especially given climate breakdown, rising sea levels, increased rainfall, and flooding.”

Zane’s law would align the UK with “global best practice for the protection of communities from hazardous land,” she added. 

A ‘reactive approach’

Local authorities are required to keep a register of land that is known to be contaminated, and to inspect any sites that could be contaminated, but one expert said there has been an “erosion of funding” to do this work.

Councils used to be able to bid for money through the Contaminated Land Capital programme, which the EA administered, but this grant ended in 2017.

“Local authorities will be aware of problematic sites, but due to the lack of adequate funding, they have had to adopt a reactive approach,” explained Dr Grant Richardson, an environmental consultant specialising in landfills and contaminated land.

“If there’s no obvious risk of harm or pollution emanating from these sites, nothing will be done to investigate or remediate them unless sites come to be developed,” he added. “That means there are likely hundreds or potentially thousands of sites that have not been properly investigated that could be leaching contaminants at harmful levels into the environment.”

Councils in England are struggling with a funding gap that could reach £8bn by 2028/29, a spokesperson for the Local Government Association, a membership body for local authorities, told Unearthed, adding: “Without adequate funding, councils will continue to struggle to provide crucial services – with devastating consequences for those who rely on them.”

The central government is stepping up funding to councils, a spokesperson for Defra said.

Our investigation found confusion over who is responsible for regulating and monitoring historic landfills. In two instances, local authorities who Unearthed contacted about potentially hazardous former landfills in their regions told us that the EA was responsible – even though the agency has stated publiclythat it is “not the regulator of former landfill sites”.

A spokesperson for the EA told Unearthed: “While the responsibility for dealing with contaminated land in England, including historic landfills, lies with local authorities, we continue to support them in carrying out their duties set out clearly under environmental regulations.”

Information on who holds the licence for these historic landfills is lacking. Out of the 105 landfills that flooded since 2000, 13 have no licence holder listed at all. Across the country, more than 8,600 – 43% – ofhistoric landfills have no licence holder listed and no date for when a licence was surrendered. 

Charles Watson, founder of environmental campaign group River Action, said: “Environmental protection in the UK has been subject over the last decade and a half to round after round of defunding from government. However, failure to provide adequate funding to regulate something as basic as landfill sites that could be leaching highly hazardous waste is all the more shocking.

“If our regulators can’t sort out how to protect us from pollutants that in theory have already been ‘safely’ disposed of, then we have little hope of ever seeing a holistic approach to combatting the wider sources of water pollution.”