The Department of Defense (DoD) has a need for new, environmentally friendly foaming agents and foam stabilizers to replace fluorosurfactants in aqueous firefighting foams (AFFF). New surfactants have been introduced into the market; however, none have yet been found to meet the current DoD performance requirements defined in MIL-F-24385F. The toxicity and environmental persistence of novel surfactants that are being developed, and even recent replacement formulations used currently in the firefighting industry, are not well established and still are under investigation.

The primary research objectives of this project are to:

1. Compare the nominal toxicities of per- and polyfluoroalkyl substance (PFAS)-free whole-foam formulations relative to the short-chain AFFF formulations currently used by the DoD;
2. Conduct chronic exposure experiments with environmentally-relevant receptors and endpoints using bioassays consistent with good laboratory practice (GLP); and
3. Rank the relative toxicity of each foam formulation.

Controlled toxicity tests designed to fill class-specific data gaps will be used to compare the nominal toxicities of PFAS-free foam formulations relative to the short-chain AFFF formulations currently used by the DoD. The project team will use both acute and subacute oral exposures as part of the study design. Since uncertainty associated with toxicity increases with taxonomic distance, the laboratory vertebrate model was chosen to best represent the species within its vertebrate class (Mammalia). Limitations such as availability, ease of care and breeding in captivity, and general husbandry limitations were considered for model species selection. The traditional laboratory rodent species, Mus, will be used to assess mammalian toxicity. Results from these studies will help refine dose determination for reproductive and developmental toxicity studies.

The results from this project will help select PFAS-free surfactant formulations that are being developed and tested to meet the current DoD performance requirements defined in MIL-F-24385F. It is anticipated that these new formulations will be either less toxic or less persistent than the current class of chemicals they are intended to replace.