PFAS Hazardous Substance Designation

PFAS Hazardous Substance Designation: Navigating the Challenges and Opportunities in Environmental Regulation

Introduction

The recent surge in attention toward per- and polyfluoroalkyl substances (PFAS) has prompted significant changes in environmental regulation, primarily driven by their designation as hazardous substances. For environmental engineers, municipal directors, and regulatory compliance officers, understanding the implications of PFAS hazardous substance designation is paramount. As of early 2025, the Environmental Protection Agency (EPA) has officially classified several PFAS compounds as hazardous, sparking urgent discussions about water treatment options, public health risks, and compliance strategies. This article delves deep into the implications of this designation, offering insights and recommendations for effective management and mitigation of PFAS contaminants.

The designation is one of the legal developments covered in our guide to PFAS regulatory and legal issues. For the wastewater discharge side, see our article on the NPDES permit for PFAS; for obligations toward customers, see PFAS public notification requirements.

Understanding PFAS: Composition and Health Risks

What Are PFAS?

PFAS, often dubbed “forever chemicals,” consist of a broad class of nearly 5,000 synthetic compounds characterized by strong carbon-fluorine bonds. This unique composition provides remarkable resistance to heat, oil, and water, which is why PFAS have been widely used in industrial applications and consumer products, from nonstick cookware to firefighting foams.

Health Risks Associated with PFAS

Recent studies indicate a strong correlation between PFAS exposure and a range of adverse health effects, including:

  • Cancer: Epidemiological analyses suggest elevated risks of kidney and testicular cancers among populations exposed to high PFAS levels.
  • Thyroid Dysfunction: Research indicates that PFAS can disrupt endocrine function, leading to thyroid disorders that affect metabolism and overall health.
  • Immune System Impacts: Data from 2024 shows that PFAS exposure is linked to reduced vaccine efficacy and increased susceptibility to infectious diseases.

According to the CDC, these health risks have become a significant public concern, prompting advocacy for stringent regulatory measures.

Regulatory Landscape: The Evolution of PFAS Designation

Recent Developments in Regulation

As of July 2025, the EPA’s hazardous substance designation of select PFAS compounds marks a pivotal shift in environmental policy. This designation requires intensive reporting and cleanup efforts under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Key developments include:

Current status of the CERCLA designation: EPA’s final rule designating PFOA and PFOS, including their salts and structural isomers, as hazardous substances under CERCLA was issued in April 2024. After a review, EPA told the court in September 2025 that it would retain the designation and defend it. On August 18, 2026, the U.S. Court of Appeals for the D.C. Circuit unanimously rejected the industry challenge in Chamber of Commerce v. EPA, so the designation remains in effect. Further review, by the full D.C. Circuit or the Supreme Court, remains possible.

Precision matters here, because the designation covers only two PFAS, PFOA and PFOS, rather than “several PFAS compounds.” Other PFAS, including GenX, are not CERCLA hazardous substances, although EPA has signaled it may develop a framework for considering further designations. What the designation actually does:

  • Release reporting: a release of one pound or more of PFOA or PFOS within 24 hours, the reportable quantity, must be reported to the National Response Center.
  • Cleanup authority: EPA can investigate and order response actions at sites contaminated with PFOA or PFOS, and they can drive Superfund listing and cleanup decisions.
  • Liability: EPA and other parties can recover response costs from potentially responsible parties. CERCLA liability is strict, can be joint and several, and applies retroactively to past disposal.
  • Natural resource damages: the designation provides the legal predicate for federal and state trustees to pursue natural resource damage claims.
  • Establishment of Maximum Contaminant Levels (MCLs): New regulations stipulate MCLs for certain PFAS in drinking water, currently set at 4 parts per trillion (ppt) for PFOA and PFOS.
  • Mandatory Reporting Requirements: Facilities that produce or use PFAS in significant quantities are now required to report releases to appropriate state and federal authorities.

One distinction to keep clear: the drinking water MCLs listed above come from a separate statute, the Safe Drinking Water Act, and are not part of the CERCLA designation. The two are frequently described together, but they impose different obligations on different parties, as summarized below.

Regulatory status, current as of this revision: EPA finalized the PFAS National Primary Drinking Water Regulation on April 10, 2024, setting enforceable maximum contaminant levels of 4.0 parts per trillion each for PFOA and PFOS, 10 parts per trillion each for PFHxS, PFNA and HFPO-DA (GenX), and a Hazard Index for mixtures of PFHxS, PFNA, HFPO-DA and PFBS. Public water systems must complete initial monitoring by 2027. In May 2026 EPA published two proposed rules: one would retain the PFOA and PFOS limits while allowing systems to request an extension of the compliance date from 2029 to 2031, and the other would rescind the limits for PFHxS, PFNA, HFPO-DA and the Hazard Index. Both remain proposals and related litigation is ongoing, so the status of those four is unsettled. Many states maintain their own enforceable PFAS standards, unaffected by the federal proposals. Because this area is under active rulemaking, re-check EPA and state sources before relying on any figure here.

Implications for Stakeholders

  1. Municipal Authorities: Cities across the United States, particularly those with known PFAS contamination sites, must develop comprehensive strategies for monitoring, reporting, and eliminating PFAS from their water systems.

  2. Industrial Operators: Manufacturers will need to reassess their processes to mitigate PFAS release, considering alternative substances and improved containment measures.

  3. Environmental Consultants: There is an increasing demand for expert guidance on compliance with new regulations, including site assessments, risk evaluations, and remediation strategies.

For water and wastewater utilities, the most important issue is one the list above omits: passive receiver liability. Utilities did not manufacture or use PFOA or PFOS, but they receive it in raw water or influent and pass it on in biosolids, spent GAC and resin, membrane concentrate, and effluent. Because CERCLA liability can attach to anyone who arranged for disposal of a hazardous substance, utilities, landfills, and farms that land-apply biosolids could in principle be drawn into cost-recovery claims.

EPA addressed this in April 2024 with a PFAS enforcement discretion and settlement policy, stating that it does not intend to pursue community water systems, publicly owned treatment works, municipal landfills, and farms applying biosolids, among others, where they are not otherwise responsible for the contamination. The limitation is that this is an EPA policy, not a statutory exemption. It does not bind private parties or states, who can still bring contribution or cost-recovery actions. When it announced it would retain the designation in 2025, EPA said it would work with Congress on passive receiver protections, and bills to create a statutory exemption have been introduced, but none had been enacted at the time of writing. Practical steps for utilities include documenting the sources of PFAS in their influent, keeping records of how residuals are handled and where they go, and reviewing contracts with haulers and disposal sites.

Technical Approaches for PFAS Management

Assessing Contamination Sources

Identifying the sources of PFAS contamination is critical for effective management. Common sources include:

  • Aqueous Film-Forming Foams (AFFF): Widely used in firefighting, these foams are a significant contributor to PFAS found in groundwater.
  • Industrial Discharges: Facilities that produce or utilize PFAS in manufacturing processes can inadvertently contaminate nearby water supplies.

Treatment Technologies

To mitigate PFAS contamination, several advanced water treatment technologies are being explored and implemented:

  1. Granular Activated Carbon (GAC): GAC can effectively adsorb PFAS compounds, although its effectiveness can vary based on specific PFAS chemistry and concentration levels.

    • Efficiency Rating: Industry analysis from 2024 indicates that GAC can reduce PFAS levels by over 90% in some cases. Continuous monitoring and periodic replacement of filters are essential.

  2. Ion Exchange Resins: Effective for various PFAS types, these resins selectively remove specific contaminants from water, allowing for higher removal efficiencies.

    • Cost-Effectiveness: Initial costs can be higher than GAC, but overall life-cycle costs may be lower due to reduced waste generation.

  3. Reverse Osmosis (RO): Provides high removal efficiencies for PFAS, making it suitable for both drinking water and industrial applications.

    • Operational Challenges: While RO is highly effective, it also generates a concentrated waste stream that must be managed, complicating regulatory compliance.

Regulatory Compliance and Best Practices

To navigate the complex regulatory landscape, entities must adhere to specific best practices:

  • Regular Monitoring: Drinking water systems should implement routine testing for PFAS levels to ensure compliance with the new MCLs.
  • Community Engagement: Transparency is crucial. Municipal managers should keep communities informed about PFAS monitoring efforts and remediation plans to build trust and foster cooperation.
  • Continuous Education: Stakeholders need to stay informed about evolving regulations, scientific research, and emerging PFAS treatment technologies.

Case Studies: Lessons Learned from PFAS Remediation Efforts

Remediation in North Carolina

The Cape Fear River contamination incident highlighted substantial PFAS contamination originating from chemical manufacturing plants. The state implemented an aggressive response plan, including:

  • Comprehensive Site Assessments: The state conducted extensive evaluations of affected properties and water systems.
  • Innovative Treatment Solutions: Municipalities tested various emerging technologies, including pilot-scale projects using ion exchange and advanced oxidation processes, aiming for sustainable solutions.
  • Two notes on this example. The principal contaminant in the Cape Fear River was GenX and related compounds from a fluorochemical manufacturing facility, and GenX is not covered by the CERCLA designation, which applies only to PFOA and PFOS. And advanced oxidation should not be presented as a PFAS treatment option: hydroxyl radicals cannot break the carbon-fluorine bond, and AOPs can convert precursors into regulated PFAS. The utility responses in the region have relied on established separation technologies such as granular activated carbon and reverse osmosis.

Lessons from California

California has been at the forefront of addressing PFAS contamination. The state’s stringent regulations and innovative monitoring programs serve as a model for others. Key strategies include:

  • Collaborative Framework: California’s multi-agency approach fosters inter-agency collaboration and community involvement.
  • Public Funding for Remediation: The introduction of state-funded programs has assisted local governments in managing remediation efforts effectively.

Conclusion

The hazardous substance designation for PFAS marks a significant chapter in environmental regulation, underscoring the importance of rapid, effective responses to contamination issues. For environmental engineers, municipal authorities, and industrial operators, the landscape is both challenging and ripe with opportunity. Utilizing advanced technologies, adhering to new regulatory frameworks, and fostering community engagement can lead to successful PFAS management strategies.

As we look toward the future, ongoing research, technological advancements, and strong regulatory practices will be crucial in mitigating the risks associated with PFAS. The landscape continues to evolve, and stakeholders must remain vigilant and proactive in their efforts to protect public health and the environment. By understanding the complexity of PFAS regulation and treatment, we can move toward a cleaner, safer future.