Replacing AFFF matters, but residual PFAS can remain in systems, waste streams, soil, and water
Aqueous film-forming foam (AFFF) is a firefighting foam designed for high-hazard flammable liquid fires. It works by spreading across the fuel surface, helping to suppress vapours, control the fire, and reduce the risk of reignition. For decades, this made it an essential safety tool for airports, ports, refineries, chemical plants, defence facilities, maritime operations, and emergency response teams.
Many legacy AFFF products contain per- and polyfluoroalkyl substances (PFAS) – a broad family of highly persistent chemicals now subject to growing regulatory and public scrutiny. Where these foams have been stored, tested, or used to extinguish a fire, PFAS may have entered equipment, waste streams, soil, or water.¹
As restrictions tighten, the move to so-called ‘fluorine-free’ foam is accelerating. It is the right direction, but it is not, on its own, proof that the PFAS risk has gone.
The key lesson from AFFF transition work is simple: changing the foam is not the same as cleaning the system, managing the waste, or understanding historical contamination.
The hidden residue problem
A firefighting system that has stored, mixed, or discharged AFFF may carry a legacy inside it. PFAS can remain in tanks, pipework, pumps, valves, hoses, seals, proportioning systems, and other wetted surfaces. When new ‘fluorine-free’ foam is introduced, those residues may migrate back into the replacement product.
Recent research on fire suppression systems confirms this challenge, showing that when systems previously containing AFFF are transitioned to ‘PFAS-free’ formulations, PFAS can dissolve from wetted surfaces and release into the new foam. Further studies also highlight the risk of rebound from contaminated infrastructure if systems are transitioned without appropriate cleaning.2,3
Why PFASafe® matters in the transition
SGS developed PFASafe as a staged analytical approach that combines screening, target analysis, and TOP Assay to provide a more complete understanding of both known and hidden PFAS. In firefighting foam, this matters because a narrow target list may identify regulated compounds, but it may not capture the broader fluorinated load or precursor compounds that can transform over time.⁴
PFASafe helps move the discussion from a single result to a clearer risk picture. Total Organic Fluorine screening can indicate the broader organic fluorine load. Target analysis can quantify known PFAS such as PFOS, PFOA, and PFHxS. TOP Assay can help reveal precursor-related risk by showing PFAS that may become measurable after oxidation.
The value of this approach is its logic. The results guide the next step rather than assuming every site needs the same testing package, helping organisations distinguish between product, system residue, waste, and wider environmental issues.
Define the claim before making it
‘PFAS-free’ should not be treated as a simple label, as the wording can be misleading. Any such claim needs a clearly defined scope and a sound analytical basis. In practice, the more defensible conclusion is ‘no PFAS detected’ within the scope of the testing performed, with that scope clearly stated.
Does it apply to the foam concentrate as supplied? The foam after installation? The cleaned equipment? The rinsate? The wastewater? The surrounding soil and groundwater?
Each question requires different evidence. A supplier declaration may support procurement, but it does not prove that historical residues have been removed from the system. A clean-out may reduce concentrations, but it does not automatically address previous releases to drainage systems, soil, surface water or groundwater.
A more robust approach is to define exactly what has been assessed: which material or system was tested, which PFAS were included, which method was used, what reporting limits applied, and what the results can reasonably support.
Clean-up is an environmental programme
Foam transition is more than a product replacement exercise; it can become an environmental risk management programme.
Removing legacy foam can generate PFAS-containing waste, including rinse water, residual concentrate, filters, absorbents, and contaminated equipment. Where AFFF has been used during training, testing, or emergency response, assessment may also need to extend beyond the firefighting system.
The regulatory direction is clear. In the EU, 23 October 2026 is an important implementation milestone under Regulation (EU) 2025/1988 for PFAS-containing firefighting foams, including stock and PFAS-containing waste such as wastewater above defined thresholds. The same regulation notes that PFAS residues may remain in equipment and may be present in newly installed fluorine-free firefighting foams, even after cleaning in line with best available techniques.⁵
Before calling a system ‘PFAS-free’, ask:
Has the old foam been removed? Has the system been cleaned? Has rinsate or wastewater been tested? Has the replacement foam been tested after installation? Has rebound from wetted surfaces been considered? Have historical releases to soil or water been assessed? At most, the result can support a conclusion of ‘no PFAS detected’ within the defined testing scope.
From replacement to confidence with SGS
Publicly available work supporting the European Commission on guidance for transitioning to fluorine-free firefighting foams reinforces the practical nature of the challenge: operators and authorities need clear approaches for inventory, planning, clean-up, waste management, sampling, documentation, and long-term confidence.⁶
This is where SGS has an important role to play. Through PFASafe, a testing strategy toolbox created to help organisations properly assess PFAS risk, and wider EHS testing, monitoring, and assessment expertise, SGS helps clients move from uncertainty to evidence. That means understanding what is present, where it may remain, how it may move, and what action is justified.
The shift to so-called ‘fluorine-free’ foam is positive and necessary, but it does not demonstrate that PFAS risk has disappeared. The key question is whether legacy residues, waste streams, and historical environmental impacts have been properly understood.
With more than 20 years of PFAS testing experience, SGS can support your testing requirements worldwide through our extensive laboratory network across Europe, North America, Asia and Australia. Learn more today. ⁷
About the author
Luca Fagiuoli, Global Business Development Manager – Environmental Testing, SGS.
Luca Fagiuoli leads global business development for environmental testing at SGS and coordinates the global PFAS working group, supporting organisations with PFAS testing strategies, regulatory compliance, and environmental risk assessment.
References
- European Chemicals Agency (ECHA), EU Guidance for transitioning to Fluorine-Free Firefighting Foams, March 2026
- Anderson, J. et al., Characterization of PFAS residuals: A case study on PFAS content in a firefighting foam delivery system of an aircraft rescue and firefighting vehicle, Chemosphere, 370 (2025), 143916. DOI: 10.1016/j.chemosphere.2024.143916
- Lang, J.R. et al., Characterization of per- and polyfluoroalkyl substances on fire suppression system piping and optimization of removal methods, Chemosphere, 308, Part 2 (2022), 136254. DOI: 10.1016/j.chemosphere.2022.136254
- SGS, PFASafe – Next Level Analysis; SGS, Environmental PFAS Sampling & Testing
- European Commission, Commission Regulation (EU) 2025/1988 of 2 October 2025 amending Annex XVII to Regulation (EC) No 1907/2006 of the European Parliament and of the Council as regards per- and polyfluoroalkyl substances in firefighting foams, OJ L, 2025/1988, 3 October 2025, including corrigendum of 8 September 2026
- Ramboll, Aiding the transition to fluorine-free firefighting foams, 2026
- SGS, PFAS Testing; SGS, Environmental PFAS Sampling & Testing
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