Per- and polyfluoroalkyl substances (“PFAS”) have been a cause for growing health-related, environmental and social concern. Yet, while PFAS are gaining an increasingly high profile in the UK and greater regulatory focus, there remains a lack of regulatory certainty, and central messaging on the subject is not clear. What does this mean for development? 

This article explores how PFAS may constitute an “emerging risk” to development, touches on some key points for developers to consider and provides an insight into how to mitigate potential risks.

What are PFAS, and why have they become a growing concern?

PFAS are a large class of thousands of synthetic chemicals that have been widely used throughout society since the 1940s. Owing to PFAS’ strong chemical properties, which are resistant to degradation, they are sometimes referred to as “forever chemicals”. While PFAS’ ability to repel grease, oil, water, and heat has led to their use in a range of products, – from firefighting foams to food packaging – there is growing concern about both widespread environmental contamination and human health risks from PFAS exposure. 

Across the UK and EU, increased regulatory scrutiny of PFAS is evident: in the UK, the Environment Agency (the “EA”) has an ongoing programme of work to understand the scale and nature of PFAS; the Health and Safety Executive (the “HSE”) published in March 2023 a paper detailing the most appropriate regulatory management options for dealing with PFAS[1]; CIRIA’s “PFAS Forum” aims to put together the UK’s first guidance on risk assessment and management of PFAS; and DEFRA and the HSE have identified the restriction of PFAS in fire-fighting foams as a key priority for UK regulation of chemicals (see our recent article on this development for more information).[2] Meanwhile, at a European level, the European Chemicals Agency (“ECHA”) is progressing work on a proposal to restrict the manufacture, placing on the market and use of around 10,000 PFAS. 

How and why are those concerns impacting development?

There is evidence that the increased scrutiny of PFAS, coupled with regulatory uncertainty, is impacting development projects and causing delays. The reasons behind the delays may be attributed to all or a combination of the following: insurer anxiety; regulatory confusion; and unforeseen costs. 

Insurer anxiety 

In the UK, PFAS have been utilised in products across many industries in society for almost 100 years. Their persistency in the environment and resistance to degradation means that PFAS can be detected in rainwater “almost anywhere on Earth”.[3] Therefore, tracing the origin of PFAS on development sites where PFAS may have already been present for decades and where there may be multiple entities who are responsible for its occurrence (some of which may no longer exist) becomes an arduous and almost impossible task. For insurers, this prompts key questions: where does liability lie? Who is responsible for the costs of remediation? How is that remediation envisaged to take place? Ultimately, an insurer’s PFAS exposure can be difficult to quantify because of this lack of or uncertainty around historical data and the nascent science. 

As stated by the large insurance company, AXA, in its environmental white paper, “Previous site investigations may not contemplate current or emerging contaminants such as 1,4-dioxane, perchlorate, and PFAS that are presently garnering regulatory attention. These types of analytical oversights can result in costly change orders, legal disputes, or claims during redevelopment.”[4]The growing anxiety around PFAS and the risk of insurers shying away from potential development projects may ultimately result in buyer unease, leaving developers with undevelopable assets. 

Regulatory confusion

Even if insurers are content to proceed with insuring sites which have not yet been tested for PFAS, or where PFAS is evident, regulatory intervention cannot be discounted and there remains questions over how remediation of PFAS is to be carried out.

There is anecdotal evidence that development projects affected by PFAS are stalling owing to the need to to test the site retrospectively for PFAS and re-assess before the projects can move forward. A number of these projects may have already gone through planning and consultation, having not considered PFAS at the time site investigations were conducted. However, regulators are now asking developers to return to sites to undertake further chemical tests. There is also a growing risk that regulators may wish to include PFAS as part of any installation permit surrender and associated remediation works before any re-development or divestment can take place.

Regulatory guidance relating to the remediation of land within the UK tends to point towards the Land Contamination Risk Management guidance (“LCRM”).[5] Further guidance is due from CIRIA which aims to explore the PFAS-specific aspects of complying with LCRM. However, this has not yet been published and there is a paucity of guidance generally for developers and landowners on how to manage and remediate land potentially affected by PFAS. PFAS contaminated soils and water is also notoriously difficult to treat. 

Unforeseen costs

Thirdly, and perhaps most importantly, PFAS appears to be impacting and is likely to impact development increasingly by creating unforeseen costs for developers. These costs have the potential to delay or even cause whole projects to halt.

For example, in the soils and waste industry, developers may be required to treat contaminated material onsite or transport contaminated soil to hazardous waste landfill sites, which may be hundreds of miles away from the development site. Both of these requirements incur significant costs. Sampling itself requires an additional layer of planning and fees, while insurers may request third-party expert legal and technical opinions before agreeing to insure a new development site. On the whole, increasing concerns and considerations arising from the presence of PFAS on-site are likely to result in further costs for developers.

How can developers mitigate these risks?

While PFAS may appear to be a daunting prospect, developers can put in place steps to mitigate the chances of issues relating to PFAS stalling or halting development projects:

  • At an early stage, include an investigation into the presence of PFAS  when carrying out due diligence and land contamination testing;
  • Engage and communicate with regulators early; 
  • Consider and include the possible costs of treating or removing PFAS-contaminated soil, water or waste prior to committing to new projects;
  • Engage with insurers to determine their stance on PFAS and whether the insurance they will provide is viable from a costs and risk perspective; and
  • Keep up to date with guidance – PFAS is an evolving regulatory area and the direction of travel appears to be increasing regulatory scrutiny.

Key takeaways

PFAS is clearly a growing concern for the development industry. However, it is worth remembering that the industry has encountered and dealt with novel contaminants in the past (oxygenates and asbestos, for example).

While regulatory guidance is currently sparse, we expect to see more certainty going forwards. The EA commenced a multi-phase project in 2019 to understand more about PFAS occurrence in the UK and the level of risk that PFAS poses. As part of its ongoing investigation into PFAS, the EA is due to publish site profiles, which should help to provide a greater understanding of the types of sites and activities where PFAS release is likely to have occurred or may be ongoing.[6]

The development industry can also expect to see an increase in technology-driven solutions in response to PFAS contamination. In a three-year collaboration, global remediation company, REGENESIS, and engineering and development consultancy firm, Mott MacDonald, have successfully implemented a sustainable remediation solution for PFAS-contaminated groundwater at an airfield in England.[7] The project, which was completed through the injection of “PlumeStop” to create a passive underground water filtration zone, won the “Best application of remediation technologies” Award at the Brownfield Awards in 2023. This project demonstrates the capacity to treat PFAS-related contamination at development sites and offers hope that technology will be a viable solution when dealing with PFAS contamination going forwards. 

When viewed more positively, robust, risk-based management of PFAS  can actually help developers bring forward sites even as regulations and regulators tighten up. 

Article by Victoria Barnes and Scarlett Sullivan


[1]Analysis of the most appropriate regulatory management options (

[2]Rationale for prioritising substances in the UK REACH work programme: 2023 to 2024 - GOV.UK (

[3]Rainwater everywhere on Earth unsafe to drink due to forever chemicals - Water Europe

[4]Site redevelopment: Understanding and managing environmental risks (

[5]LCRM: Stage 1 risk assessment - GOV.UK (

[6]Poly- and perfluoroalkyl substances (PFAS): sources, pathways and environmental data - report (