The Legal Consequences of High PFAS Background Levels
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The legal landscape for per- and polyfluoroalkyl substances is rapidly changing. Last year, the US Environmental Protection Agency (USEPA) issued nonbinding lifetime health advisories for four types of PFAS. Most recently, on March 14, 2023, USEPA proposed maximum contaminant levels (MCLs) for PFAS in public drinking water systems.

PFAS have been used in innumerable industries and consumer products, from aerospace to food packaging. The strong carbon-fluorine bond that makes PFAS so useful in so many applications also tends to make them resistant to degradation in the environment. Once released into the environment, these compounds often gradually disperse and accumulate in media, circulating through the environment in what has come to be known as the “PFAS cycle.” Significant transport mechanisms in the PFAS cycle include stack emissions leading to aerial deposition, aqueous firefighting foam use, stormwater discharges, wastewater discharges, on- and off-site disposal, and landfill leachate.

In 2023, the USEPA is expected to finalize its designation of two PFAS—perfluorooctanoic acid, or PFOA, and perfluorooctane sulfonic acid, or PFOS—as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the Superfund law. Concurrently, a flurry of state-level PFAS regulations are in effect or in the process of being promulgated. These new federal and state regulations will only accelerate tort claims related to PFAS contamination and exposures. The sheer number of new PFAS regulations is striking by itself, but the remarkably low regulatory limits are just as salient.

As opposed to natural background contamination, where geologic forces deposit a naturally occurring hazardous substance at a location, anthropogenic background results from historical human activity, such as when an area has undergone a long period of industrial use or was built upon fill material. This white paper focuses on anthropogenic sources of background PFAS contamination. Unlike other contaminants, where sources can often be traced back to a single location or operation, “PFAS background” conditions tend to be more convoluted, with a multitude of potential point sources combined with more widespread diffuse sources.

The ubiquity of certain PFAS in the environment, their resistance to degradation, and the development of exceptionally low regulatory limits for PFAS is an unprecedented combination, with potentially profound legal consequences.

Put simply, enforceable regulatory limits are already descending below PFAS background levels for certain regions, with the USEPA's recent health advisory levels and proposed MCLs almost certainly falling below background levels measured in some places. This could affect numerous legal areas, from regulatory compliance to tort actions claiming property damage or personal injury from PFAS. In essence, defendants who aren't thinking about PFAS background could be missing a critical opportunity, and plaintiffs who aren't considering it before bringing a case are doing so at their risk.

This white paper explores the current science and understanding of PFAS background in precipitation, groundwater, and soil and offers questions that can help during initial site characterization. The authors then address common legal implications of cleanup criteria, standards, and the fact that enforceable regulatory limits are often below PFAS background levels.

Whether in a regulatory or litigation setting, the issue of PFAS background may be lurking underneath any attempt to connect PFAS contamination to a particular source. An array of analytical tools can be used to understand whether PFAS are located at a site, associated with a particular exposure pathway, or can reasonably be attributed to background levels. Legal practitioners would be wise to always consider the potential influence of PFAS background — and to be fully apprised of the analytical tools that can help differentiate background.

Publication Summary

  • Geosyntec Authors: Wayne Amber, Dylan Eberle, Mary Ensch, Caitlin Johnson, Thomas Wanzek, and Kaylin McDermett
  • All Authors: Grant Gilezan, Paul Stewart, Wayne Amber, Dylan Eberle, Mary Ensch, Caitlin Johnson, Thomas Wanzek, and Kaylin McDermett
  • Title: The Legal Consequences of High PFAS Background Levels
  • Event or Publication: Publication
  • Practice Areas: PFAS, groundwater assessment and remediation, Contaminated site assessment, conceptual site model development, contaminated media investigations, remediation system operation, and due diligence
  • Date: April 2023
  • Publication Type: Academic Research