New findings reveal the toxicity of firefighting foams that do not contain per- and polyfluoroalkyl substances (PFAS) – human-made chemicals used in industrial and consumer products. Historic aqueous film-forming foams (AFFF) used in firefighting contain PFAS, which are harmful to the environment, aquatic animals and humans and can persist in bodily tissues for decades. Due to the level of toxicity and hazards associated with PFAS, the Department of War (previously Department of Defense) mandated the replacement of AFFF containing PFAS products in the 2020 Defense Authorization Act. The U.S. Department of War Strategic Environmental Research and Development Program (SERDP) has been actively engaging in research to explore and identify PFAS-free foam options for firefighting foams.
In coordination with the U.S. Army Corps of Engineers and the National Institute of Standards and Technology, scientists with National Oceanic and Atmospheric Administration’s (NOAA’s) National Centers for Coastal Ocean Science (NCCOS) participated in a multi-year research effort supporting the SERDP to develop and evaluate the efficacy and toxicity of PFAS-free firefighting foams (F3s) to meet the U.S. Department of War performance requirements. This research focuses on four tasks with a goal of developing data to determine the toxicity of PFAS-free F3s relative to PFAS-containing AFFF products and their acute and chronic toxicity to fish and aquatic invertebrates.
For the first task, the team identified six PFAS-free F3s to investigate, along with one AFFF (containing PFAS) to use as comparison, and developed a standard protocol for handling, measuring, and testing the toxicity of the foams. The team used multiple species from fresh and saltwater or estuarine conditions for the purpose of this experiment.
Task two reported the immediate toxicity impacts of the six selected F3s on both freshwater and marine fish and aquatic invertebrates. One compound tested (identified as AF1) was generally the most toxic for most species while the one containing PFAS was generally the least toxic.
Task three detailed the possible persistence of toxicity over time, which accounts for effects of aging, transformation and degradation in the environment. Reasons for this degradation may include transforming into a gas and escaping into the atmosphere, and the process of light or water breaking down the chemical compounds. All three compounds tested revealed a decrease in toxicity with aging and little to no toxicity after three to four weeks.
Finally, Task four reported the possible impact of the six F3 compounds and the AFFF product on growth and reproduction of both freshwater and marine fish and aquatic invertebrates when chronically exposed to sublethal concentrations of these products. For each taxa tested, the compounds were rated using EPA’s five-step scale of toxicity categories. Results determined that
- Algae and invertebrates are more sensitive to F3 compounds than fish.
- Fresh and marine invertebrates experienced greater alterations in growth and development when exposed to F3 compounds compared to AFFF.
- Juvenile mysids (a shrimp-like crustacean) were observed to mature more slowly when exposed to F3 compounds relative to those exposed to AFFF.
- Clam shell growth is more impacted when exposed to F3s than the AFFF.
- Overall most species experienced similar or greater chronic toxicity with the F3s than the AFFF.
The Department of War will use findings from this report, along with efficacy and human health assessments, to guide decisions to approve firefighting foams for future use.