A report published by the Environment Agency concludes that high-temperature incineration (HTI) remains the only proven, commercially viable method for large-scale destruction of per- and polyfluoroalkyl substances (PFAS), the so-called “forever chemicals”. However, HTI must operate under strict conditions to ensure effectiveness, say the authors.

The analysis “Rapid evidence assessment of PFAS incineration and alternative remediation methods”, published in September 2025, examined more than a thousand peer-reviewed papers and government studies, evaluating how thermal and non-thermal methods perform in breaking down PFAS. From the examination of 232 studies, extracting data and insights from work undertaken around the world, the authors say this final document offers “a comprehensive overview of current knowledge regarding PFAS incineration and remediation technique”.

PFAS persistence and the incineration challenge
PFAS have been widely used for decades in industrial and consumer products, from firefighting foams and textiles to non-stick cookware. Their extreme chemical stability has made them useful—but also nearly indestructible in the environment. As regulatory bans phase in across Europe and the UK, governments are facing the urgent question of how to dispose of legacy PFAS waste safely.

The report finds that, while a range of alternative technologies are emerging, only incineration above 1,000 °C—ideally 1,100 °C with a two-to-three-second residence time—can achieve near-complete PFAS mineralisation. When operated under optimal conditions with sufficient oxygen, turbulence, and hydrogen sources in the combustion environment, destruction efficiencies exceeding 99.99% were achieved for PFAS-containing firefighting foams and similar wastes.

However, the report cautions that many existing waste-to-energy and hazardous-waste incinerators may not consistently reach these thresholds. In England, most facilities operate close to their design limits and rarely adjust conditions specifically for PFAS-bearing wastes, meaning that residual emissions or partially degraded by-products—known as products of incomplete combustion (PICs)—could occur if operating parameters are suboptimal.

Complex chemistry and formation of by-products
The Environment Agency highlights that PFAS destruction involves complex high-temperature chemistry. Studies reviewed show that decomposition of common PFAS such as PFOA and PFOS begins at 300–400 °C, but complete mineralisation typically requires at least 1,000 °C. Below that, short-chain PFAS and volatile fluorinated compounds such as trifluoroacetic acid (TFA) can form, presenting new exposure risks.

At the molecular level, PFAS breakdown proceeds through the formation of fluorocarbon radicals and intermediates like acyl fluorides, which can recombine or form stable by-products if insufficient hydrogen or oxygen is available. The report notes that maintaining an adequate hydrogen-to-fluorine ratio—via moisture or additives such as calcium hydroxide—helps stabilise fluorine as calcium fluoride (CaF₂), improving overall mineralisation and reducing harmful emissions.

Alternative methods still experimental
The Environment Agency reviewed existing scientific literature on a wide range of emerging PFAS destruction and remediation technologies, including plasma oxidation, mechanochemical degradation, supercritical water oxidation (SCWO), gasification, pyrolysis, sonolysis, and electrochemical oxidation.

While many of these methods show promising results in laboratory or pilot-scale studies, the report emphasises that none have yet been proven at commercial scale for mixed or solid PFAS wastes. Most can only treat PFAS in aqueous form and often face challenges such as high energy demand, limited scalability, or incomplete understanding of by-products.

The review suggests that integrated “treatment train” systems, combining separation and destruction steps—for instance, foam fractionation followed by thermal or chemical breakdown—may offer a more sustainable route in the future. However, these approaches require further demonstration to establish their environmental safety and cost-effectiveness.

Regulatory and international context
The report also situates its findings within global policy developments. The US Department of Defense has maintained a moratorium on PFAS incineration pending further data, while the European Chemicals Agency (ECHA) has acknowledged that PFAS destruction efficiencies (in this report’s words) “may not always be 100%,” with residual PFAS released to air or retained in bottom/fly ash. In the UK, bans on PFOS, PFHxS, and PFOA firefighting foams under the Stockholm Convention and EU Regulation 2019/1021 have made incineration the mandated route for irreversible destruction of these materials.

Need for monitoring and research
Despite the apparent effectiveness of HTI, the report underscores significant data gaps in monitoring PFAS and PICs emissions from full-scale facilities. It calls for improved analytical methods, such as adoption of the US EPA’s OTM-45 and OTM-50 protocols, to verify real-world destruction performance and ensure no secondary pollution.

The Environment Agency concludes that while high-temperature incineration is currently indispensable, it is not a long-term solution. More research into scalable, lower-impact technologies and life-cycle assessments is essential to guide investment and regulation.
“HTI can achieve near complete mineralisation under optimal conditions,” the report states, while also noting that “its long-term role may be limited by high energy demands, technical constraints, environmental uncertainties and its carbon footprint.”

For waste operators, the findings reinforce the importance of strict temperature control, residence time, and feedstock management when handling PFAS-laden wastes.