PFAS at Superfund: The CERCLA Enforcement Era Begins
The April 2024 designation of PFOA and PFOS as CERCLA hazardous substances transformed the legal landscape for PFAS contaminated site remediation in the United States. For the first time, EPA has the authority to compel cleanup of PFAS contamination using the full suite of CERCLA enforcement tools: unilateral administrative orders (UAOs); enforcement agreements with potentially responsible parties (PRPs); cost recovery actions for past EPA expenditures; and natural resource damage claims for PFAS impacts on groundwater, surface water, and biota. The first wave of PFAS-specific CERCLA enforcement actions is now underway, establishing the scope, pace, and methodology of what will ultimately be one of the largest environmental remediation programs in US history.
How CERCLA Works for PFAS Sites
CERCLA’s enforcement mechanism identifies potentially responsible parties (PRPs)—current and former owners/operators, arrangers for disposal, and transporters—who are strictly, jointly, and severally liable for contamination at a site. For PFAS sites, PRPs may include: current property owners (military installations, airports, industrial facilities); former AFFF manufacturers (3M, DuPont/Chemours, Tyco Fire Products); industrial PFAS users who arranged for disposal of PFAS-containing waste; and municipalities or waste haulers who transported PFAS-contaminated materials. EPA’s first step is typically placing a site on the National Priorities List (NPL)—the Superfund list—or issuing a Removal Action to address immediate threats. NPL listing triggers formal remedial investigation/feasibility study (RI/FS) processes that can take 5–15 years to complete before full remediation begins.
EPA’s Enforcement Discretion Guidance
EPA’s 2024 enforcement discretion guidance committed to prioritizing enforcement against “significant contributors” of PFAS to the environment—specifically PFAS manufacturers, those who knowingly used and disposed of PFAS products while aware of health risks, and federal facilities. EPA committed to generally not pursuing CERCLA enforcement against municipal water utilities for PFAS in biosolids, wastewater treatment plant effluent, or drinking water distribution—provided the utility was acting in good faith compliance with applicable regulations at the time. This enforcement discretion policy provides important protection for municipal water systems but does not prevent private litigation by property owners and communities against utilities for PFAS contamination. Industrial companies with PFAS disposal histories, and particularly former AFFF manufacturers not covered by the MDL 2873 settlements, face acute CERCLA enforcement exposure.
Cleanup Standards and Remedial Action Objectives
CERCLA cleanup at PFAS sites must be conducted to meet Remedial Action Objectives (RAOs) that protect human health and the environment. For PFAS-contaminated groundwater serving as drinking water, the RAOs will be based on the 2024 NPDWR MCLs—4 ppt for PFOA and PFOS in drinking water. For other exposure pathways (subsistence fishing, incidental soil ingestion), EPA is developing PFAS-specific exposure factors and risk-based screening levels. The challenge: achieving 4 ppt in contaminated groundwater through pump-and-treat may not be technically feasible in all hydrogeological settings within any reasonable timeframe—raising difficult questions about what “cleanup” means when contamination is below current treatment thresholds. EPA’s remediation guidance for PFAS Superfund sites is expected to provide pathway-specific cleanup standards and acceptable residual risk frameworks by 2025.
CERCLA designation of PFOA and PFOS as hazardous substances is the regulatory action that makes the Federal Government’s commitment to PFAS cleanup financially and legally enforceable—creating the largest environmental remediation program since the original Superfund cleanup era of the 1980s and 1990s.