As fluorosurfactants termed per- and polyfluoroalkyl substances (PFAS) used in firefighting foams since the 1960s are being discovered in drinking water, above safe levels in multiple countries, it’s clear that the use of all PFAS (C6 and C8) firefighting foams will soon be curtailed by advancing regulations.
The detection of PFAS in beer, cider, milk, eggs, game and livestock provides examples of their permanence and mobility in the environment.1,2,3 The elevated levels reported in human breast milk indicate the potential for some PFAS to bioaccumulate and concentrate in humans,4 with concentrations of some PFAS in human breast milk being tenfold higher than in individuals drinking water.
Exposure to a wide array of differing PFAS still used in firefighting foams via ingestion of food and water continues whilst an understanding of their toxicology evolves. As levels of the legacy C8 PFAS diminish in human blood, some studies reveal that replacement unknown PFAS are taking their place.5
As the use of all firefighting foams containing fluorosurfactants will face restrictions globally, it seems that now is the time to transition to alternative foams devoid of any alternative persistent chemistries, such as siloxanes. There are many factors to bear in mind for end users of foams regarding implementing foam transition, as there are a few challenges to consider when transitioning to fluorine-free firefighting (F3) foams.
The PFAS backdrop
The reality is that perfluorinated organics such as fluorosurfactants were identified as being highly stable, not amenable to biodegradation and thus persistent in the environment since 1962.6 so it was easy to predict that their use in firefighting foams would lead to permanent environmental damage. As the use of firefighting foams – such as aqueous film forming foams (AFFF) and fluoroprotein foams (FFFP and FP) – represents potentially the most environmentally emissive uses of these ultra-persistent and highly mobile chemicals, through both training exercises and incident response, the uses of PFASs in firefighting are perceived to cause an increased potential for environmental impacts.
The legacy of using PFAS-containing foams to extinguish fires (and train or test equipment) lives long after the fires are extinguished and can lead to significant long-term environmental liabilities7 which can far exceed the value of the asset being protected from fire. The potential for permanent damage to water supply aquifers can lead to the need to remove PFAS from water pumped for drinking water for hundreds of years to come.
Fluorine-free firefighting (F3) foams, such as training foams have been available since 1985, with commercially available F3 foams developed to completely replace AFFF sold since 2002.8 These F3 foams had equivalent or superior performance to C8 AFFF in ICAO tests published in 2002, so many sectors such as civil aviation (Heathrow Airport etc.), oil and gas companies (Equinor etc.) and the military (Royal Danish Airforce) adopted F3 foams several years ago and have very positive reflections regarding their extinguishment performance.9
An evolving regulatory landscape
A series of regulatory pincer movements are currently focused on preventing future use of PFAS and protecting human health as a result of PFAS contamination to aquifers and surface waters, which often feed drinking-water supplies. Significantly lower drinking-water standards are being promulgated globally, mainly focused on legacy C8 PFAS,10 but many countries are also now regulating C6 PFAS.11 These shorter-chain C6 PFAS have a greater potential to impact drinking water because of their increased environmental mobility vs C8, and can be much more expensive to remove from water via conventional treatment technologies.
US regulations addressing the use of firefighting foams containing PFAS have so far been proposed or enacted in multiple states.9 Recent proposals have assigned $10B to monitor and remediate PFAS in drinking water12 whilst levels of some PFAS proposed as safe in drinking water diminish to 2ng/L in the State of Illinois, with similar levels proposed in several other States.13
In Europe, stockpile regulations stipulate that if more than 50L of foam is held at a site, the nature and volume of foam needs to be reported to regulators if the perfluorooctanoic acid (PFOA) content exceeds 25mg/L (parts per billion), or if PFOA related compounds, termed PFOA-precursors, exceed 1,000mg/L. Then a timeline of regulations addressing PFAS stipulates that the foams classed as stockpiles can only be used when 100% contained from 2022. Then by 2023 stockpiles require incineration if 100% containment is not possible. In 2024 these foams cannot be used and by 2025 there is a deadline to incinerate any remaining stockpiles. The European Chemicals Agency (ECHA) has recently proposed an EU-wide restriction that will prevent and reduce the emissions of C6 PFAS within the EU14 whilst proposing a specific action plan focused on PFAS.15
In Australia the Queensland Department of Environment and Science (DES) foam policy provides guidance on the off-site disposal of waste foam concentrate and contaminated water.16,17 Specifically, the policy states that: ‘Notwithstanding that firefighting foams containing PFOS and PFOA must not be held or used, water contaminated by fluorinated organic compounds must not be released to the environment if the levels of fluorinated organics exceed 0.3 µg/L PFOS, 0.3 µg/L PFOA and 1.0 µg/L for sum of TOP Assay C4-C14 plus C4-C8 sulfonates.’
In January 2018, the South Australian government amended the Environment Protection (Water Quality) Policy 2015 under the Environmental Protection Act 1993 to ban the use of potentially hazardous fluorinated firefighting foams. Under this legislation, all PFAS containing firefighting foams are banned and there is no maximum allowable concentration for PFAS in operational foams used in South Australia.9
The industry group LASTFIRE, which is funded on a non-profit basis by fuel-storage companies, develops best-practice guidance for storage-tank protection, free from the often commercial bias of foam manufacturers.18
LASTFIRE has carried out an extensive series of tests using ‘new generation’ foams of both C6 and F3 types. These tests were aimed specifically at storage-tank related scenarios but have relevance to all foam applications. Fire tests have involved a range of incident scenarios including tank fires, dike area fires and general spill fires as well as standard test protocols such as EN1568 and LASTFIRE.
The LASTFIRE standard test protocol was developed, initially by Mobil Research and Development Corporation but finalised by LASTFIRE, specifically to evaluate foam performance for the critical application of tank fires – an example of a test simulating a specific application, as all performance-based tests should be for critical situations. The work of LASTFIRE is ongoing, but the most recent large-scale tests involved 40m x 7m spill fires with Jet A fuel and were carried out in cooperation with DFW Airport Research and Training Facility.19
LASTFIRE are keen to emphasise that the research is ongoing and further tests are planned. Conclusions regarding foam performance should not be generic, as there are examples of varying levels of effectiveness and performance for each foam category on the market. The results show that F3 Foams can successfully extinguish both spill and tank fires using standard application rates – and indeed at more critical application rates too, given the correct application techniques and foam quality.
It will be crucial when choosing a F3 foam that it is also a non-persistent foam, meaning that all of the ingredients in the foam are fully biodegradable. If there are components of the foam that persist such as siloxanes, this can lead to future environmental liabilities. Environment Canada assessments were reported to conclude that cyclotetrasiloxane and cylcopentasiloxane, also known as D4 and D5, are toxic, persistent and have the potential to bioaccumulate in aquatic organisms.20 It is important to highlight that biological oxygen demand (BOD) and chemical oxygen demand (COD) tests done on foam is not an appropriate measure to determine whether the foam is biodegradable, as these tests need to be done on each individual component of the foam. Showing a BOD/COD ratio for a whole foam could mask the fact that a small percentage of its components are extremely persistent.
The safest option to avoid future environmental liabilities when considering which foams to transition to is to use the GreenScreen Certified standard for firefighting foams.21,22
Approaches to decontamination
Decontamination of firefighting and fire-suppression equipment is essential to limit carryover of PFAS to the new F3 foams. Fluorosurfactants form multiple bilayers in a crystalline matrix on surfaces, which can form a coating which acts as a reservoir of PFAS that requires removal from fire-suppression systems via effective decontamination. Triple rinses with water are not sufficient to remove PFAS layers entrained throughout fire-suppression systems and leads to a significant volume of decontamination water that requires treatment. Some 1.6g/L of PFAS has appeared in F3 foams after water rinsing between foam changeouts.9
Tetra Tech recommends using a specially formulated biodegradable cleaning agents termed PFAScrub to effectively remove the reservoir of PFAS crystalline bilayers which form on the interior of fire-suppression systems, to limit both future liabilities and cost associated with PFAS contaminating F3 foams because of inadequate decontamination. On site regeneration of the PFAScrub reagent to extract PFAS from it as a concentrate also leads to significantly reduced waste disposal costs.
Firefighting foam concentrate disposal is under significant scrutiny in the US with litigation progressing.23 There are unresolved questions on the fate of PFAS present in liquid waste streams subject to incineration. When incinerating liquids, temperatures required for thermal destruction of PFAS will result in steam discharge from the stack, which has been observed during long-term flue-gas sampling to include PFOS and PFOA. Post-combustion data indicates residuals of PFOS were observed in laboratory incineration trials and in municipal solid waste ash.24
A former incinerator ash lagoon in Michigan is under investigation as a potential source of PFAS25 and there are reports PFAS being detected in soil and water close to an incinerator,26 which may indicate that residual liabilities associated with incineration of AFFF concentrates are not extinguished by application of this treatment process. However, despite concerns of incomplete combustion of PFAS in liquid matrices during incineration, incineration remains the primary destruction technology for PFAS in many jurisdictions.27
The transition to F3 foam will usually require minor foam supply system modifications, which typically only involve modifications to the foam proportioner, so are generally inexpensive. Multiple Newtonian F3 foams are now available which can potentially be used with existing proportioners.9
As accreditation of the modified suppression systems can be a hurdle to overcome when dealing with insurers, via its teaming partners Tetra Tech can perform extinguishment tests using the new foam and equipment at the facility, to demonstrate effectiveness. These tests are then presented to insurers to allay any concerns if specific items of equipment are not yet accredited for the F3 foams.
Looking forwards: PFAS on the global agenda
The growing concerns regarding drinking-water impacts from PFAS is driving a dramatically increased regulatory, media and political focus. At the same time, the performance of F3 foams at extinguishing fires has markedly improved such that its performance is comparable to AFFF. So now the balance between the perceived risk of transitioning to F3 foams, versus the potential harm caused and liabilities associated with continued use of PFAS-based foams, makes evaluation of how to move away from C8 and C6 PFAS based foams a wise commercial decision.
For more information, go to www.tetratecheurope.com
- Death, C., et al., Per- and polyfluoroalkyl substances (PFAS) in livestock and game species: A review. Sci Total Environ, 2021. 774: p. 144795.
- Göckener, B., et al., Transfer of Per- and Polyfluoroalkyl Substances (PFAS) from Feed into the Eggs of Laying Hens. Part 1: Analytical Results Including a Modified Total Oxidizable Precursor Assay. Journal of Agricultural and Food Chemistry, 2020. 68(45): p. 12527-12538.
- Clarke, A., Luksemburg, W. J., Patterson, A., Roberts, B., and Schneider, E., Analysis of Per and PolyfluorinatedAlkyl Substances in an International Selection of Beer and Cider, in Emerging Contaminants Summit. 2016, Vista Analytical Laboratory, El Dorado Hills, CA USA: Denver.
- Perkins, T. Study finds alarming levels of ‘forever chemicals’ in US mothers’ breast milk. Available from: https://www.theguardian.com/environment/2021/may/13/pfas-forever-chemicals-breast-milk-us-study.
- Yeung, L.W.Y. and S.A. Mabury, Are humans exposed to increasing amounts of unidentified organofluorine? Environmental Chemistry, 2016. 13(1).
- Goldman, P., Enzymology of Carbon-Halogen Bonds, in Degradation of Synthetic Organic Molecules in the Biosphere; Natural, Pesticidal and Various Other Man-Made Compounds. 1972, Nat. Acad. of Sci.,: Washington, DC. p. 147-165.
- Ross I, Toase D. Richards, S. , Persistent Liabilities – Navigating PFAS Risks. JOIFF Catalyst, 2021. Q2 2021: p. 18.
- L, K.D.M.R., Forever Chemicals Environmental, Economic, and Social Equity Concerns with PFAS in the Environment. 2021.
- Ross, I. and P. Storch. Foam Transition: Is it as simple as “foam out / foam in?”. Catalyst 2020; 1-19]. Available from: https://joiff.com/wp-content/uploads/2020/05/JOIFF-Catalyst-Q2-Foam-Supplement-13May20.pdf.
- Ross, I. Expert Opinion: Is the UK sleepwalking into a PFAS contamination nightmare? 2021; Available from: https://environment-analyst.com/uk/106678/expert-opinion-is-the-uk-sleepwalking-into-a-pfas-contamination-nightmare.
- Ross, I., Hurst, J., . Managing Risks and Liabilities associated with Per- and Polyfluoroalkyl Substances (PFASs). CL:AIRE Technical Bulletin TB19 2019; Available from: https://www.claire.co.uk/component/phocadownload/category/17-technical-bulletins?download=668:tb-19-managing-risks-and-liabilities-associated-with-per-and-polyfluoroalkyl-substances-pfass-2019.
- Olson, E.D. Biden Proposes Big Investments in Water: It’s About Time. 2021; Available from: https://www.nrdc.org/experts/erik-d-olson/biden-proposes-big-investments-water-its-about-time.
- S., L.T. PFAS Update: Current State-by-State Groundwater Regulations. 2021; Available from: https://www.bclplaw.com/en-GB/insights/pfas-update-current-state-by-state-groundwater-regulations.html.
- (ECHA), E.C.A., ANNEX XV RESTRICTION REPORT PROPOSAL FOR A RESTRICTION SUBSTANCE NAMES: Undecafluorohexanoic acid (PFHxA), its salts and related substances. 2019.
- Commission, E. Poly- and perfluoroalkyl substances (PFAS) Chemicals Strategy for Sustainability Towards a Toxic-Free Environment. 2020; Available from: https://ec.europa.eu/environment/pdf/chemicals/2020/10/SWD_PFAS.pdf.
- Queensland, S.o., Operational Policy – Environmental Management of Firefighting Foam. 2016.
- Queensland, S.o. Environmental Management of Firefighting Foam Policy Explanatory Notes Revision 2. 2016; Available from: https://environment.des.qld.gov.au/assets/documents/regulation/firefighting-foam-policy-notes.pdf.
- LASTFIRE. Large Atmospheric Storage Tank Fires. Available from: http://www.lastfire.co.uk/default.aspx?ReturnUrl=%2.
- Systems, A. DFW Fire Testing. Available from: https://www.youtube.com/watch?v=uXyGlYHw_ZM&t=33s.
- Suzuki, D. The Dirty Dozen: Siloxanes. 2010; Available from: https://davidsuzuki.org/queen-of-green/dirty-dozen-siloxanes/.
- Action, C.P. GreenScreen® Method for Safer Chemicals. 2018; Available from: https://www.greenscreenchemicals.org/method/full-greenscreen-method.
- Franjevic, S., Schreder, E., Plant, D., Krause, R. GreenScreen Certified™ Standard for Firefighting Foam. 2020; Available from: https://www.greenscreenchemicals.org/resources/entry/webinar-gsc-fff.
- KALMUSS-KATZ, J. COMPLAINT FOR DECLARATORY AND INJUNCTIVE RELIEF. 2020; Available from: https://earthjustice.org/sites/default/files/files/filed_complaint_-_pfas_incineration_suit.pdf.
- Horst, J., McDonough, J., Ross I., Houtz, E., Understanding and Managing the Potential By-Products of PFAS Destruction. Ground Water, 2020. 48(5): p. 627-32.
- Kent County, Grand Rapids, Grand Rapids Water Resource Recovery Facility, Former Incinerator Ash Lagoon. 2020; Available from: https://www.michigan.gov/pfasresponse/0,9038,7-365-86511_95645-529272–,00.html.
- Lerner, S. TOXIC PFAS FALLOUT FOUND NEAR INCINERATOR IN UPSTATE NEW YORK. 2020; Available from: https://theintercept.com/2020/04/28/toxic-pfas-afff-upstate-new-york/.
- Ross, I. DISPOSAL OF AFFF, FFFP AND FP: CHALLENGES AND EMERGING SOLUTIONS. 2020; Available from: https://issuu.com/joiff/docs/catalyst_20q4_20final/s/11240502.