Q.01

What is AFFF firefighting foam?

AFFF (aqueous film forming foam) is a firefighting foam made for Class B fires, meaning burning liquid fuels such as gasoline, diesel and jet fuel. It works because it contains fluorocarbon surfactants, which are PFAS: the foam lays down a film over the fuel that puts out the fire (US EPA research presentation, slide 2). In the EPA's words, the foam creates "a foam blanket to extinguish a fuel fire" (EPA, Red Hill AFFF spill). Those PFAS are the reason AFFF is now heavily regulated.

Approach: I searched the Stockholm Convention POPs list, the EU POPs Regulation list held by ECHA, Belgian PFAS guidance and Japan's chemical control (CSCL) legislation, then opened two US EPA pages for the technical description.

How it works and what's in it

  • Use: Mainly fuel fires. Foam concentrate is mixed with water before use. The US military specification (MIL-PRF-24385F) has two types: Type 3, mixed at 3 parts concentrate to 97 parts water, and Type 6, mixed at 6 to 94 by volume. The same specification caps PFOA and PFOS at 800 ppb each.
  • History: Before AFFF (1940s to 1960s), protein foam was the main agent. It formed no film, so it had to cover the whole fuel surface. Fluorocarbon surfactants came in 1962. Variants followed in the 1970s, including film-forming fluoroprotein and alcohol-type AFFF, which is needed for alcohol and polar solvent fires.
  • PFAS content: The surfactants have included PFOS and other perfluoroalkane sulfonates. Most manufacturers have since moved to short-chain (C6) fluorotelomer surfactants, which the EPA notes "are still PFAS!" (EPA presentation, slides 2 and 5–7; the deck states that it reflects its authors' views, not EPA policy.)

Why regulators focus on it

  • PFHxS (Stockholm Convention, Annex A, no specific exemptions): AFFF is the first use listed for PFHxS. The Convention entry notes high clean-up costs at old and current foam training sites and airports [1].
  • PFOS (Stockholm Convention, Annex B): The PFOS listing still carries a specific exemption for "fire-fighting foam for liquid fuel vapour suppression and liquid fuel fires (Class B fires) in installed systems, including both mobile and fixed systems" [2].
  • EU: According to Belgian federal guidance:
    • The PFHxA restriction under REACH reaches firefighting foams in steps in 2026 and 2029.
    • A broader restriction on PFAS-containing firefighting foams was published in October 2025. It gives a general 5-year transition for placing foams on the market, with separate deadlines by use (fire extinguishers, training, industry, ships, offshore).
    • During the transition, users "must" keep releases to a minimum, meet labelling rules, manage stocks, waste and contaminated water, and have a management plan [3].
  • Japan: A 2010 ministerial ordinance sets handling rules for PFOS-containing extinguishers and foam. Operators "shall" store foam in sealed containers indoors on concrete or resin-coated floors, inspect containers regularly and keep records for five years, and recover foam discharged in training [4][5][6].

If it helps, I can go through the EU firefighting-foam restriction in detail: the deadline for each use and the PFAS concentration limits.

Q.02

Why are PFAS firefighting foams restricted?

PFAS firefighting foams are restricted because the PFAS in them are extremely persistent, often mobile, and potentially hazardous. Foam use puts them straight into the environment, where they build up and cannot practically be cleaned out. In ECHA's opinion on the EU-wide restriction, the Risk Assessment Committee (RAC) found that PFAS foams pose a risk to the environment and to human health that "is not adequately controlled" [7]. The Socio-Economic Analysis Committee (SEAC) added that workable fluorine-free alternatives exist for most uses [8].

Approach: I read the RAC and SEAC opinions on the EU restriction of PFAS in firefighting foams (which ECHA's restriction tracker maps to Annex XVII entry 82), the Annex XVII PFHxA entry, the Stockholm Convention listings, Belgian FPS Health guidance and UK HSE analyses. The opinions give the scientific reasons; I did not open the October 2025 restriction regulation itself.

1. Persistence, so the problem grows with every use

  • RAC treated PFAS as "non-threshold substances", handled like PBT/vPvB substances (persistent, bioaccumulative and toxic, or very persistent and very bioaccumulative). For these, releases stand in for risk and "should be minimised". Nearly all PFAS are persistent and many are bioaccumulative, but the group as a whole has not been shown to meet the formal PBT/vPvB criteria [9].
  • No "safe" environmental concentration can be set. Even if one were, it "will eventually and inevitably be exceeded over time due to the cumulative nature of the exposure" [10].
  • Exposure of wildlife and people is "continuous and irreversible". If further hazards come to light later, "it may be too late to take action" because of what has already built up in the environment [10].

2. Foam use is a direct, large release

  • RAC agreed that essentially all PFAS in foams end up in the environment, either directly during use or through poor waste treatment. It accepted an estimate of about 470 tonnes a year [9].
  • The evidence: PFAS contamination of groundwater, soil and surface water near EU airports, military bases and fire-drill sites where fluorinated foams were used for training or firefighting [10].
  • RAC named formulation, testing, training and use as release sources, and said it is "practically impossible to remove pollution once it has occurred" [7].
  • UK HSE's analysis reached the same view: the foams "may be released directly into the environment", which makes firefighting foam a reasonable candidate for restriction [11].

3. Mobility and cross-border pollution, so national bans are not enough

  • PFAS can travel long distances through waterways and become a transboundary problem [7].
  • SEAC agreed that national measures "would not adequately manage the risks". It also wanted to avoid different PFAS definitions in different Member States distorting trade in foams [12].

4. Known hazards of individual PFAS

  • For PFOA, the Stockholm Convention entry cites long-range transport, bioaccumulation, adverse effects in wildlife, and links to kidney and testicular cancer, thyroid disease and high cholesterol. It also states that alternatives exist for all PFOA uses in firefighting foams [13].
  • UK REACH restricts PFOA (entry 68) because of its PBT properties [14].

5. Alternatives exist, and doing nothing is expensive

  • SEAC concluded that technically and economically feasible fluorine-free alternatives can be brought in for most uses by the end of the transition periods. RAC judged their hazards "likely to be significantly lower", with siloxane-based alternatives a possible exception [8].
  • For certain Seveso sites and offshore oil and gas installations, SEAC said performance is not yet fully demonstrated. Because a failed fire response there could be catastrophic, it called for a review of substitution before their transition periods end [15].
  • Estimated cost of the chosen option: about €6.8 billion (range €3-17 billion) over 30 years [15]. On the other side, SEAC's PFHxA opinion cites Nordic Council estimates of €821 million to €170 billion for remediating PFAS at European level [16].

6. Stopping one PFAS from simply replacing another

  • SEAC warned that leaving one PFAS group unregulated "could undermine the benefits of the earlier restrictions" (PFOS, PFOA, C9-C14 PFCAs, PFHxS). That is why foams are now covered by the broad PFAS restriction as well as the substance-specific ones [16].
  • Example: under Annex XVII, PFHxA foams for training, testing and public fire services "shall not" be placed on the market or used from 10 April 2026 at or above 25 ppb (PFHxA and its salts) or 1 000 ppb (PFHxA-related substances). Civil aviation follows from 10 October 2029 [17].

The same reasoning appears outside the EU. Belgian guidance describes the October 2025 restriction as a step "to further limit PFAS emissions" [3]. UK HSE notes that historical foam use at training grounds is Australia's biggest source of concentrated PFAS emissions [18].

Q.03

How should old firefighting foam be disposed of?

In the EU, old PFAS foam concentrate has to be sent for destruction that keeps PFAS releases as low as possible. In practice that means high-temperature incineration or co-incineration at 1,100 °C or more. It must never go to sewage or biological wastewater treatment, and you need to keep proof of how it was disposed of. Those conditions are taken from the final RAC/SEAC opinion behind the EU firefighting-foam restriction (REACH Annex XVII entry 82). The adopted text is Regulation (EU) 2025/1988 [19], but I couldn't open it on EUR-Lex, so I can't confirm the final legal wording.

Approach: I searched ECHA's restriction files and Annex XVII entries, the EU POPs Regulation list, Belgian guidance, the GB POPs guidance and Japan's chemical control (CSCL) texts, and opened the US EPA's PFAS destruction guidance. The GB POPs guidance had nothing on foam.

EU: the restriction conditions (final RAC/SEAC opinion)

  • Stocks you need to get rid of (para 5): From six months after entry into force, foam held in stock above the PFAS threshold "shall be handled for adequate treatment." That treatment has to keep PFAS releases as low as technically and practically possible, and it excludes "any biological wastewater treatment, sewage treatment, irrespective of any pre-treatment." If the foam is incinerated or co-incinerated, "the temperature shall be at least 1 100 °C." Proof of disposal "shall be documented and kept available for enforcement authorities" [20].
  • Firewater run-off and cleaning waste (para 4(d)): The same treatment rules apply to collected waste from foam use. They also apply to waste from cleaning foam equipment where total PFAS is above 1 mg/L [21]. In another version of the opinion conditions, the cleaning-waste limit is 50 mg/L for offshore oil and gas and 1 mg/L for all other sectors [22].
  • Management plan: Each site's plan must set out how liquid and solid wastes will be contained, treated and disposed of. It must cover waste from foam use, routine cleaning and maintenance, and spills. The plan must be reviewed at least once a year [21].
  • Labelling (para 6): Containers of firewater run-off and other PFAS waste must carry "WARNING: Contains per- and polyfluoroalkyl substances (PFAS)". So must cleaning-waste containers above 1 mg/L total PFAS [20].
  • Belgian guidance confirms that under the adopted October 2025 measure, users "must" manage stocks, waste and contaminated water properly. It also points to a European technical guide on best practice [3].

EU: legacy PFOS, PFOA or PFHxS foam These three substances fall under the EU POPs Regulation (EU) 2019/1021. All three are listed in Annex I Part A (banned) and Annex IV (waste concentration limits) [23][24][25]. The records I found do not give the actual limit values.

What the restriction dossier says about methods

  • The only adequate disposal option stakeholders identified was high-temperature incineration, in hazardous waste incinerators or cement kilns. Landfill and ordinary municipal or industrial wastewater treatment were ruled out because they do not destroy the PFAS. Some suppliers have taken old foam back, sometimes only if fluorine-free replacement foam is bought [26].
  • At 1,100 °C or more, PFAS usually break down to CO₂ and HF. What forms at lower temperatures has not been established [27].
  • Destruction cost is estimated at about €1 per litre [28].
  • RAC is concerned about how practical it is to transport and incinerate dilute wastewater, because few sites can take it [29].
  • When you switch foams, the tanks and fire vehicles also need cleaning. Of the nine cleaning protocols compared, seven send the rinse waste for high-temperature incineration [30].

Japan (PFOS foam, 2010 rules)

  • Recovered foam, rinse water and wiping cloths "shall" be put in sealed containers and stored indoors [5][6].
  • The waste must be disposed of properly by the company itself, or handed to a licensed waste disposal operator "based on applicable acts and ordinances" [31].

United States The EPA's 2026 Interim Guidance on PFAS destruction and disposal covers AFFF and is "non-binding" (EPA). It names three options with lower potential for PFAS release (EPA fact sheet):

  • permitted Class I injection wells;
  • RCRA Subtitle C hazardous waste landfills;
  • permitted hazardous waste combustors "that operate under certain conditions".

It also notes that landfilling "could result in higher PFAS releases" than EPA thought in 2024.

Q.04