PFAS are synthetic chemicals where some (poly) or all (per) of the carbon-hydrogen bonds have been replaced by carbon-fluorine bonds. The carbon-fluorine bond is one of the strongest bonds known in chemistry and gives PFAS a wide range of unique physical and chemical properties: oil and stain resistance, water resistance/proofing, chemical and thermal stability, and friction reduction. Two of the most widely used and studied PFAS are Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS). PFOA and PFOS have been used as non-stick and stain-resistant coatings, industrial surfactants, and as aqueous film-forming foams (AFFF), used for fighting Class B fires. In the 2000s, PFOA and PFAS were voluntarily phased out by manufacturers in the United States. GenX chemicals (hexafluoropropylene oxide or HFPO dimer acid and its ammonium salt) and PFBS (Perfluorobutane Sulfonic Acid and its potassium salt) are shorter-chain PFAS that were developed to replace PFOA and PFOS.

Although research is still ongoing, studies suggest that PFAS may lead to reproductive effects such as decreased fertility or increased high blood pressure in pregnant women; developmental effects or delays in children; increased risk of some cancers; reduced immune system function; and increased cholesterol levels. Further information regarding the current understanding of the human health and environmental risks of PFAS is available from the United States Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR)

Due to their widespread use, PFAS have been found in water, soil, air, building materials, clothing, bio-solids, food, and food related products. Consequently, studies show that most people in the United States have low levels of PFAS in their bodies. Studies have also shown that PFAS levels can be more elevated in people that live or have lived near a source for a long period of time, indicating that PFAS may accumulate in the human body over time. Ingestion is the primary route of exposure to PFAS, mainly through drinking water from PFAS-impacted aquifers or other PFAS-impacted water sources.

No known PFAS production has occurred in Wyoming and only a few industries that commonly use PFAS occur in Wyoming. However, because PFAS are present in many consumer products. PFAS chemicals may have accumulated in biosolids, wastewater, landfills, and industrial sites in the State and may be found near military facilities and airports that used AFFF.

In 2018 the Wyoming Department of Environmental Quality (WDEQ) funded a study to conduct an initial inventory and prioritization of potential sources of PFAS, primarily based on proximity to priority drinking water aquifers. The following facility types were included in the site inventory:

• Potential AFFF use and storage locations (e.g., local fire departments, airports)
• Biosolids generators
• Department of Defense and National Guard facilities
• Hydrocarbon storage or processing facilities (e.g., petroleum refineries, natural gas processing plants)
• Landfills (municipal, industrial, and construction and demolition waste)
• Wastewater facilities
• Other industries that have been associated with PFAS use (e.g., tanneries and metal plating)

Based on the prioritization system, aquifers in proximity to sites with AFFF were the most likely to have PFAS. The WDEQ will conduct an additional study to assess the potential source areas identified during the 2018 study and investigate additional potential PFAS sources in Wyoming, and any potential impacts to groundwater.

In 2016 the United States Environmental Protection Agency (EPA) published Health Advisory (HA) levels for PFOS and PFOA in drinking water. The HAs are not regulatory and are intended to inform monitoring and other activities to protect public health. The HAs represent EPA’s assessment of health risks based on the best available science and identify levels to protect all people, including sensitive populations and life stages, from adverse health effects resulting from a lifetime of exposure to these PFAS in drinking water and other potential sources of exposure (e.g., food, air, consumer products).

In June 2022, EPA updated the HA values for PFOA and PFOS and issued new HAs for two additional PFAS compounds, GenX chemicals, and PFBS. Under the PFAS Strategic Roadmap initiative, EPA is currently in the process of developing National Drinking Water Regulations for PFAS under the Safe Drinking Water Act.

WDEQ is committed to closely following the scientific research and EPA’s actions for PFAS, particularly as our knowledge of the potential effects of PFAS on people, animals, and the environment grows.

United States Environmental Protection Agency: https://www.epa.gov/pfas
Interstate Technical Regulatory Council: https://pfas-1.itrcweb.org/

Association of State and Territorial Solid Waste Management Officials: https://pfas.astswmo.org/

Agency for Toxic Substances and Disease Registry: https://www.atsdr.cdc.gov/pfas/index.html