The Louisville Water Company, which supplies tap water to Louisville, Kentucky, routinely tests its water for various substances, including per- and polyfluoroalkyl substances (PFAS). PFAS are a group of synthetic chemicals used in industrial and consumer products for decades. Known for their environmental persistence, they are often referred to as "forever chemicals." Research has associated PFAS exposure with several health risks, including certain cancers and reduced immune system functioning.
Detection of Elevated PFAS Levels
In December 2024, technicians at the Louisville Water Company detected a significant increase in GenX, a specific type of PFAS, within raw water samples sourced from the Ohio River. The GenX concentration measured 52 parts per trillion (ppt), which was a 15-fold increase from the 3.4 ppt recorded the preceding month. To provide context, one part per trillion is comparable to a single drop of liquid dispersed across 20 Olympic-sized swimming pools. Despite this spike in raw water, the treated drinking water maintained GenX levels below the federal safety limits slated for implementation in 2029.
Identification of the Source
Investigations conducted by the Louisville Water Company traced these elevated GenX levels approximately 400 miles upstream on the Ohio River to the Chemours Co.'s Washington Works facility, situated near Parkersburg, West Virginia. This facility is involved in the production of fluoropolymers using GenX. Chemours was established as a spin-off from DuPont in 2015, a company with a documented history of PFAS pollution, specifically PFOA, at the same location.
Louisville Water's analysis indicated a correlation between the observed GenX spike and publicly available data regarding Chemours' chemical discharges into the Ohio River. The utility's director of water quality and research noted that potential health risks from low PFAS concentrations are typically assessed over a lifetime of exposure, and clarified that drinking water represents one of multiple potential PFAS exposure pathways, with other sources including food packaging and pre-packaged foods.
Chemours' Response and Regulatory Environment
In response to a lawsuit initiated by a West Virginia environmental advocacy group, Chemours Co. denied any connection between its discharges and the GenX spike observed in Louisville. The company further asserted that available sampling data confirmed GenX levels in the river and in downstream utilities' treated drinking water were within safe parameters.
The U.S. Environmental Protection Agency (EPA) established initial regulations for six distinct PFAS types in drinking water in 2024, with public water utilities mandated to comply by 2029. Subsequently, an announcement by a future administration outlined plans to maintain regulations for only two PFAS types (PFOA and PFOS), remove restrictions on four others, including GenX, and extend the compliance deadline to 2031. Federal studies estimate that approximately 45% of U.S. tap water contains at least one type of PFAS. The Biden administration's initial projections indicated that up to 10% of the estimated 66,000 public drinking water systems in the U.S. might require measures to reduce PFAS contamination under the original regulations.
Legal Actions and Enforcement
Chemours has reportedly exceeded its legal permit limits for chemical releases into the Ohio River on multiple occasions over several years. In 2023, the EPA initiated enforcement action against Chemours' West Virginia facility for exceeding permit limits for both GenX and PFOA. The West Virginia Rivers Coalition filed a lawsuit in 2024, alleging that the EPA's consent order regarding Chemours was not being diligently prosecuted.
In August, a federal judge issued an order for Chemours to immediately cease instances of over-pollution, a decision which the company subsequently appealed. The West Virginia Rivers Coalition publicly described the ruling as a positive development for public health and the Ohio River ecosystem.
Mitigation Strategies and Prevention
The removal of PFAS from drinking water presents a substantial financial challenge. The Louisville Water Company is currently investing approximately $23 million to upgrade its powdered activated carbon system, which is a recognized method for PFAS removal. Environmental advocates contend that preventing contaminants from entering water supplies upstream is a more cost-effective approach than post-contamination treatment.
Chemours has acknowledged permit violations and stated its collaboration with government regulators to achieve a resolution. The Louisville Water Company has indicated that sustained elevated GenX levels could complicate its future adherence to federal drinking water standards. The utility advocates for regulators to consider the impact on downstream water treatment facilities when establishing future permit conditions for upstream industrial operations.