An investigation has revealed that thousands of sites in Britain potentially contaminated with toxic chemicals have never been inspected by local councils.

Despite the potential health risks posed by substances like lead and arsenic, the vast majority of high-risk areas remain unchecked.

Of the 13,093 sites classified as high-risk by councils, only 1,465 have undergone physical inspections. This means that over 11,000 sites remain untested, raising concerns about public health and environmental safety.

The UK government maintains that local authorities are legally required under the Environmental Protection Act to identify and inspect potentially contaminated land. However, many councils argue that a lack of funding has hindered their ability to carry out these duties.

All 122 unitary authorities across Wales, Scotland, and England were contacted to gather information about contaminated sites. Of the 73 councils that responded, a staggering 430,000 potentially contaminated sites were identified in the early 2000s. Among these, 13,093 were labeled as high-risk, yet more than 85% have not been physically tested.

In Wales, half of the 22 councils either could not or would not provide figures. Among those that did respond, 698 high-risk sites were identified, of which 586 remain uninspected. The lack of comprehensive inspections leaves many communities vulnerable to the unseen dangers beneath their feet.

This investigation coincides with the release of the Netflix drama Toxic Town, which dramatises one of the UK’s most notorious environmental scandals. The findings bring renewed attention to the legacy of Britain’s industrial past and the potential health hazards it continues to pose.

Contaminated land is defined as any site polluted by previous industrial use, such as former factories, power stations, railway lines, landfill sites, petrol stations, or dry cleaners. While properties built after 2000 are generally covered by updated planning regulations, homes constructed before this time are less stringently monitored.

One area of concern is Cwmystwyth in north Ceredigion, where remnants of abandoned metal mines pose significant environmental hazards. The region, home to more than 400 of Wales’ 1,300 disused mines, contains some of the UK’s most polluted rivers, including the Ystwyth, Rheidol, and Clarach. The Cwmystwyth mines date back to the Bronze Age and were abandoned in 1950. However, toxic waste materials, including zinc, cadmium, and lead, still pollute the surrounding environment.

Robin Morris, a local resident, relies on a water filtration system to protect against contamination from the nearby mines.

“We installed an advance filtration system and were assured it would take absolutely everything,” he said.

A soil sample from his garden revealed lead levels significantly exceeding the recommended safe limit for gardening. For Morris and other locals, the lingering effects of historical industrial activity are a persistent concern.

“It causes alarm bells to ring,” Robin told BBC Wales Investigates.

“In light of the figures from your soil sample, we should have stopped growing vegetables long ago.”

“We had ducks and chickens, a couple of the ducks went lame and we did consult the vet, he thought it was because of lead contamination,” added Robin.

Ceredigion council has stated that it continues to work with Natural Resources Wales to monitor and address the health impacts of the area’s mining legacy. However, experts warn that no level of lead exposure is safe.

Dr. Ian Mudway emphasises that lead contamination can affect children’s cognitive development and cause kidney and cardiovascular issues in adults.

The dangers of toxic exposure are illustrated by the case of Manon Chiswell. As a toddler, she abruptly stopped speaking, prompting medical concerns.

“I do have memories of being very closely monitored in Meithrin [nursery]… I always had an adult with me,” said Manon, now 20.

“I couldn’t speak… they had to use a traffic light system, and yes or no cards to redirect me and help me communicate.”

Initial assessments suggested autism, but further blood tests revealed dangerously high levels of lead poisoning. Her father, Huw Chiswell, believes the exposure occurred at their home in Cardiff, which is situated near an old industrial site.

“She used to eat earth [as a toddler] in the garden,” he said.

“There were railway sidings not far from where we lived at the time, so it’s difficult to draw any other conclusions really, because once she’d stopped the eating, she got better.”

Lead is not the only threat. According to a government report, the most hazardous sites are often contaminated with other toxic substances such as arsenic, nickel, chromium, and polycyclic aromatic hydrocarbons (PAHs), which can be found in soil and water. Despite these risks, many of these sites remain uninspected due to financial constraints.

Campaigners are calling for new legislation to compel councils to maintain a public register of all potentially contaminated sites. This movement, known as “Zane’s Law,” is led by the parents of Zane Gbangbola, a seven-year-old boy who died from toxic gas exposure after the River Thames flooded their home in 2014.

Zane’s parents believe the deadly fumes originated from a nearby landfill. The proposed law also seeks increased funding for councils to identify and investigate potentially hazardous sites.

“You have to know that it exists before you can protect yourself,” said Zane’s dad Kye Gbangbola, who was left paralysed after the gas poisoning.

“Until we have Zane’s Law people will remain unprotected.”

When the Environmental Protection Act was introduced 25 years ago, its advocates intended for robust oversight of contaminated land. However, former Environment Secretary John Selwyn Gummer now argues that government funding cuts have drastically reduced the number of inspections being conducted.

“There is no way in which local authorities can do this job without having the resources,” said Lord Deben.

“Successive governments have under-provided for the work that we need to do.”

Local authorities also point to financial pressures as the main reason for the decline in inspections. Phil Hartley, a former contamination officer for Newcastle City Council, describes how the removal of central government grants led to a “collapse” in site checks. Without adequate funding, councils have struggled to fulfil their statutory duties.

“Since the money dried up very, very few councils proactively go out looking for contaminated land sites because the council doesn’t want to take the risk of finding them,” said Mr Hartley.

“There’s a possibility that some people’s health is being threatened, which is not great.”

In response, the UK government insists that local authorities remain responsible for inspecting contaminated sites, requiring remediation where necessary, and maintaining public records of remediated land.

“Any risk to public health from contaminated land is a serious matter,” a spokesperson from the Department for Environment, Food and Rural Affairs said.

Additionally, the Environment Agency has been tasked with producing a new report on the state of contaminated land to establish a baseline for future policy development.

Despite these official assurances, the bodies representing councils in both Wales and England continue to assert that a lack of financial resources prevents them from meeting their legal obligations.

The Welsh Local Government Association said while Wales’ 22 councils took their responsibility to check sites “seriously”, progress was “increasingly constrained by a lack of dedicated funding and specialist resources”.

England’s Local Government Association said: “Without adequate funding, councils will continue to struggle to provide crucial services – with devastating consequences for those who rely on them.”

As thousands of potentially hazardous sites go unchecked, concerns about public health and environmental safety remain unresolved.