How do new EPA drinking water regulations define PFAS?

The U.S. Environmental Protection Agency (EPA) has sparked both praise and criticism with its newly established drinking water regulations targeting six PFAS (per- and polyfluoroalkyl substances) compounds. This marks a significant milestone, as it is the first time in over two decades that the EPA has set legal drinking water limits for a contaminant. While some environmental advocates herald the decision as "groundbreaking," others are raising serious concerns about the sufficiency of these limits and the EPA's evolving definition of PFAS. 

PFAS is a class of nearly 15,000 chemicals commonly used in the manufacturing of products that resist water, stains, and heat. Often referred to as "forever chemicals" due to their persistence in the environment, PFAS do not naturally break down. Exposure to these chemicals has been linked to a variety of health problems, including cancer, liver disease, thyroid dysfunction, birth defects, kidney disease, and weakened immunity. 

PFAS contamination in drinking water has become a prominent environmental crisis in recent years. Estimates suggest that over 200 million Americans may be affected by PFAS contamination. The EPA's response has been swifter than with any other compound in the agency's history, but some critics argue that the efforts are still insufficient. 

Under the new rules, municipal utilities must remove six specific PFAS compounds from drinking water, including PFOS and PFOA. This could lead to a cascade of lawsuits aimed at PFAS polluters, such as the U.S. military, 3M, DuPont, and Chemours. The legal limits for PFOS and PFOA have been set at 4 parts per trillion (ppt) each, a significant reduction from the previously advisory limit of 70 ppt. Still, some experts argue that these levels remain hazardous. 

While the industry claims to have voluntarily phased out PFOS and PFOA a decade ago, these compounds persist in large quantities in the environment and human blood. Even as older chemicals were phased out, new ones such as GenX and PFBS have been introduced, with growing evidence suggesting similar toxicity levels. 

The new regulations include a "health hazard index" that covers PFBS, GenX, PFHxS, and PFNA. The rules require the removal of these chemicals if they pose a combined health risk. But critics point out that the regulations only address six out of roughly 15,000 PFAS compounds and urge the EPA to regulate the entire class. 

Complicating the debate over the new limits is the EPA's changing definition of PFAS. Critics fear that the EPA's move to a "case-by-case" approach may exclude thousands of chemicals from regulation, benefiting the industry. 

The inconsistency in defining PFAS has generated confusion within the chemical industry and even within the agency itself. The European Union, Canada, and most of the scientific world have embraced a more inclusive definition, while the EPA seems to have narrowed its focus. Public health advocates warn that all PFAS should be considered persistent and toxic, leading to calls for broad restrictions on the entire chemical class. 

Some current and former EPA employees allege that the agency's definition excludes specific fluorinated chemicals used in pesticides and "ultra-short chain" PFAS refrigerants, conflicting with other global regulations. This inconsistency may have market implications and create uncertainty for chemical companies and public health. 

For example, North Carolina's Cape Fear basin has already experienced the impact of the EPA's narrower definition in their battle against decades of pollution by Chemours. The agency's 2021 response to a citizen petition declined to test for certain chemicals, citing that they did not meet the definition. 

The EPA's recent actions on PFAS mark a significant and complex development in environmental regulation. While the new drinking water limits represent a positive step toward addressing the issue, the broader debate on the definition of PFAS and the sufficiency of the regulations remains heated. 

The challenges posed by PFAS highlight the delicate balance between protecting public health and navigating a rapidly changing scientific landscape. The controversy over the EPA's definition of PFAS compounds, coupled with concerns over the adequacy of the new legal limits, demonstrates the complexity of crafting effective regulations in the face of evolving science, industry interests, and public health needs. 

As the situation continues to unfold, the pressure is on the EPA to not only safeguard drinking water but also to provide clarity and consistency in its approach to regulating these pervasive "forever chemicals." The agency's response to this multifaceted issue will undoubtedly serve as a precedent in environmental law and regulation for years to come. Whether these recent actions are seen as a substantial step forward or a missed opportunity will likely be a matter of ongoing debate and scrutiny.