PFAS Regulations Are Coming: What You Need to Know

Published On: April 21, 2023

PFAS or “per-and polyfluoryoalkyl substances” are a class of compounds (several thousand) that contain a chain of carbon and fluorine in their structure.   PFAS have been used globally for over 60 years, and are still being used because of their many useful properties – they are chemically inert; resistant to thermal breakdown; resistant to grease, oils, and water; and can act as a surfactant.  As a result of these properties, various PFAS compounds have been used in industrial chemicals and processes, household goods and clothing, food packaging, and aqueous film-forming foam (or AFFF), which is used most significantly for firefighting activities.  The same properties that make PFAS highly useful also make it problematic in the environment.  PFAS do not decompose readily (in fact, they are often called “forever chemicals”), they bioaccumulate in organisms, they are ubiquitous, and studies have shown that some PFAS compounds can have significant toxicity.  As such, states and the federal government have been increasing their regulatory efforts over the last several years.

The U.S. EPA’s PFAS Action Plan (2019) and the updated PFAS Strategic Roadmap (2021) both contained two key items that the Agency was evaluating and developing:  1) enforceable standards for PFAS in drinking water, and 2) establishing PFAS as “hazardous substances” under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), otherwise known as “Superfund”.   The U.S. EPA is moving forward on both fronts, with rulemaking efforts in both 2022 and 2023.


Proposed Federal Drinking Water Regulations

In March 2021, the U.S. EPA issued its final regulatory determination to regulate perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) under the Safe Drinking Water Act.   These actions set the stage for evaluating National Primary Drinking Water Standards for PFOA and PFOS, as well as evaluating potential regulatory actions for other PFAS.

On March 29, 2023, the U.S. EPA published the proposed PFAS Drinking Water Regulations in the Federal Register.  This proposed rule includes Maximum Contaminant Levels (MCLs) of 4.0 nanograms/L (ng/L) for two PFAS constituents (PFOA and PFOS), and an MCL using a Hazard Index of 1.0 for 4 other PFAS constituents.  The use of a combined Hazard Index (HI) for four of the PFAS constituents is a unique approach, which was developed to ensure that there are no health risks from exposures to chemical mixes as a result of “dose additivity”.


PFAS Compound EPA’s Proposed MCL Goal EPA’s Proposed MCL (enforceable levels)
PFOA (perflurooctanoic acid) Zero 4.0 nanograms/liter (ng/L, but also expressed as “parts per trillion”).
PFOS (perfluorooctane sulfonic acid) Zero 4.0 ng/L
PFNA (perfluorononanoic acid) 1.0 (unitless)

Hazard Index

1.0 (unitless)

Hazard Index

PFHxS (perfluorohexane sulfonic acid)
PFBS (perfluorobutane sulfonic acid)
HFPO-DA (hexafluoropropylene oxide dimer acid  – commonly referred to as “GenX” Chemicals.


When EPA developed the proposed standards it took into account the MCL Goals (zero for PFOA and PFOS), known or suspected toxicity, the availability of analytical methods to test for the PFAS constituents, and the availability of treatment technologies that can remove PFAS to levels below the proposed standards.

The proposed rule would require that public water systems:

  • Monitor for these PFAS constituents,
  • Notify the public of PFAS levels in the drinking water, and
  • Treat to reduce the PFAS levels if they are above any of the proposed standards.

According to EPA, roughly 66,000 public water system will be subject to his rule, and approximately 5% or more of those are anticipated to have an exceedance of a MCL.  The EPA estimated that the cost to public water systems could be up to $1.2 Billion per year for the capital expenses and O&M.  The proposed rule is in public comment through May 30, 2023, and the final rule is anticipated to be promulgated in December 2023, with an effective date of December 2026.

CERCLA Hazard Substances and PFAS

The U.S. EPA provided a Notice of Proposed Rulemaking in September 2022 that would designate PFOA and PFOS as CERCLA “hazardous substances”.   The EPA is currently assessing comments and rulemaking is underway.   Once the rule is finalized (potentially in 2023), among other things, it would require facilities to report spills greater than one pound over a 24-hour period, and would allow U.S. EPA (and states) to respond to releases or threats of releases of these compounds under their CERCLA authority.

In March 2023, the U.S. EPA conducted two listening sessions on the proposed CERCLA PFAS enforcement.  In those sessions, U.S. EPA indicated that the focus will be on the “Enforcement First” policy, which requires responsible parties to perform or pay for the cleanup.  Those parties would include PFAS manufacturers, federal facilities, and industrial parties “whose actions result in the release of significant amounts of PFAS”.  According to U.S. EPA, they will utilize their “discretionary authority”, and do not intend to pursue (under CERCLA authority) water utilities, publicly-owned wastewater treatment plants (aka, POTWs), publicly owned/operated municipal solid waste facilities, farms that apply or have applied biosolids in the past, and certain airports and fire departments.

The impacts of a CERCLA hazardous substances designation for PFAS are far-reaching.  Besides the additional reporting requirements, there are many concerns among the regulated community and other stakeholders, including the following:

  • There will likely be more sites proposed and/or identified on the CERCLA National Priorities List.
  • Potential for re-openers of previously closed CERCLA sites, including already re-developed sites.
  • Disruptions among active remediation sites (CERCLA, and others) that could require significant additional resources to address.
  • Litigation associated with cost-recovery or private party actions. Under CERCLA, even parties that had a minimal contribution to PFOA or PFOS contamination could be subject to pay for the costs of cleanup.
  • Since PFAS is ubiquitous and persistent in the environment, it is possible that it could be identified as a “recognized environmental conditions” (RECs) during “all appropriate inquiry” Phase I Environmental Site Assessments conducted as part of a property transactions. This will likely have some impact on property transactions and potential Brownfield reuse.

August Mack will continue to stay abreast of the rapidly developing PFAS rulemaking efforts.  Additional information regarding PFAS regulations will be provided in an upcoming webinar.

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