Aqueous film-forming foams (AFFF) containing per- and polyfluoroalkyl substances (PFAS) were historically used to rapidly extinguish hydrocarbon fires. There has been an emphasis on developing PFAS-free alternatives for fire suppression, and numerous firefighting foam (F3) alternatives have emerged as potential candidates. The potential effects of alternative chemistries to animals are largely unknown. As such, the primary objective of this project was to assess the relative toxicity of candidate F3 products vs. a legacy AFFF to aquatic species.

Schematic Diagram

This work focused on three aquatic species: water fleas (Daphnia magna), fathead minnows (Pimephales promelas), and larval gray treefrogs (Hyla versicolor). These three species are likely to be present at wetlands surrounding sites where F3 may be used. Acute and chronic laboratory toxicity tests were conducted with each species, and ecologically relevant endpoints (e.g., survival, reproduction, growth, development) were examined. Research included six candidate F3 alternative products and a short-chain AFFF reference product.

48-hour lethal concentration (LC) tests were used to assess the acute toxicity of each product. Across all three species, the F3 alternatives were more acutely toxic (LC50_48HR values between 17 and 942 mg/L) relative to the reference AFFF (LC50_48HR values between 999 and 2958 mg/L). However, based on the U.S. Environmental Protection Agency ecotoxicity categories, the products would be considered ‘slightly toxic’ to ‘practically nontoxic’. 

In the chronic toxicity tests, responses varied by the species, life stage, and product tested. Gray treefrog metamorphic endpoints were relatively insensitive to sublethal chronic exposure to the F3s. Similarly, adult fathead minnows were relatively tolerant of exposure to F3 alternatives. In contrast, larval fathead minnows were highly sensitive to most F3s, and there were significant reductions in mass and length with exposure. For water fleas, reproductive endpoints were somewhat affected by exposure to three of the F3 alternatives and the AFFF reference, but mainly at the highest concentration.  

This work is some of the first to test the toxicity of F3 alternatives to aquatic species. The research helped to identify the relative sensitivity of different species, important life stages, and key ecological endpoints. Although some effects were observed in laboratory tests with animals exposed F3s, field exposure, outside of an emergency releases or spills, is unlikely and ingredients in F3s rapidly degrade. Successful implementation of this research holds profound implications for improving the management of PFAS, directly addressing mission readiness by safeguarding the warfighter and communities. (Project Completion - 2025)

Fuller, N., J. G. Suski, S. Lanasa, M. K. Chanov, D. K. Jones, D. L. Haskins, K. A. Quinlin, M. A. Wigren, J. T. Hoverman, Y. J. Choi, M. S. Sepulveda, L. S. Lee, G. R. Lotufo, A. Kennedy, L. May, A. Harmon, T. Biber, N. Melby, D. W. Moore, P. B. Key, K. W. Chung, E. F. Wirth, and T.A. Anderson. 2024. Chronic Toxicity of PFAS-Free Firefighting Foams to Aquatic Organisms. Environmental Toxicology & Chemistry, 43(11):2436-2454. doi.org/10.1002/etc.5979.

Hoverman, J. T., D. K. Jones, M. E. Lech, G. A. Bianchi, D. L. Haskins, E. G. Hoffman, A. E. Johnson, J. D. Morehouse, S. J. Pfisterer, K. A. Quinlin, A. C. Valachovic, M. A. Wigren, Y. J. Choi, M. S. Sepúlveda, and L. S. Lee. 2025. Limited Effects of Fluorine-Free Foam Alternatives on Gray Treefrog (Hyla versicolor) Larval Development in Laboratory and Mesocosm Studies. Environmental Toxicology and Chemistry. doi.org/10.1093/etojnl/vgaf106.

Jones, D. K., K. A. Quinlin, M. A. Wigren, Y. J. Choi, M. S. Sepúlveda, L. S. Lee, D. L. Haskins, G. R. Lotufo, A. Kennedy, L. May, A. Harmon, T. Biber, N. Melby, M. K. Chanov, M. L. Hudson, P. B. Key, K. W. Chung, D. W. Moore, J. G. Suski, E. F. Wirth, and J. T. Hoverman. 2022. Acute Toxicity of Eight Aqueous Film-Forming Foams to 14 Aquatic Species. Environmental Science & Technology, 56(10):6078-6090. doi.org/10.1021/acs.est.1c03776.