Formatted Title

State Approaches to Regulating PFAS in a Dynamic Regulatory Environment

Background/Objectives

The regulatory environment for soil and water at the federal and state level for per- and polyfluoroalkyl substances (PFAS) is dynamic to say the least. On March 14, 2023, the U.S. Environmental Protection Agency (EPA) proposed maximum contaminant levels (MCLs) for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) and a hazard index MCL for the combination of perfluorohexane sulfonic acid (PFHxS), hexafluoropropylene oxide dimer acid and its ammonium salt (also known as GenX chemicals), perfluorononanoic acid (PFNA), and perfluorobutane sulfonic acid (PFBS). These proposed levels serve as a benchmark for states to gauge the potential future regulatory enforcement of select PFAS in drinking water. If approved, these MCLs will be enforceable and supplant state regulations. No current federal regulations for PFAS exist or are proposed for groundwater or surface water protection. For now, the regulation of PFAS to enforceable limits in drinking water, groundwater, and surface water is occurring at the state level, although EPA plans to approve the proposed MCLs in drinking water by the end of 2023. EPA established regional screening levels for PFBS, perfluorobutanoic acid, PFHxS, perfluorohexanoic acid, PFNA, PFOS, PFOA, and GenX for soil in May 2023 for both residential and industrial exposure. Various states have enacted both enforceable and non-enforceable limits for various PFAS in soil that differ significantly from federal screening levels. States have also begun regulating PFAS concentrations in soil for their potential to leach into groundwater.

Approach/Activities

We have tracked U.S. state enforcement and regulations of PFAS in water and soil for the past 4 years. During this time, various states have developed draft, proposed, or final health-based regulatory and/or guidance values for several PFAS in drinking water, groundwater, surface water, and soil. Some states have enacted enforceable standards, whereas other states have proposed guidelines or recommended levels. The threshold values for PFAS often differ from EPA past and current health advisories and from state to state given legislative constraints and evolving scientific considerations.

Results/Lessons Learned

Several states have taken unique approaches to regulating PFAS in both water and soil. New Jersey was the first state to promulgate a PFAS regulation in drinking water, with an enforceable limit for PFNA in July 2015. North Carolina followed in 2017 with the adoption of a preliminary health assessment concentration for GenX in drinking water. In total, 12 states have enforceable regulations and eight states have non-enforceable regulations of PFAS in drinking water. As of October 2023, no state regulates PFOA or PFOS in drinking water at concentrations more stringent than the EPA proposed MCLs. Washington (State Action Level for public drinking water systems) and California (Response Level) have enforceable limits for PFBS and/or PFNA that are less than the proposed hazard index MCLs (2,000 parts per trillion [ppt] for PFBS and 10 ppt for PFNA, respectively). Maine (Interim Drinking Water Standard) and Massachusetts (MCL) both have enforceable regulations for several PFAS compounds in drinking water that do not have proposed EPA MCLs. Fourteen states have an enforceable regulation for at least one PFAS in groundwater, with an additional nine states having a non-enforceable or proposed regulation. For surface water, five states have an enforceable standard, and three states have non-enforceable or proposed regulations. A similar analysis will be completed for soil with respect to both regulation of concentrations through direct exposure as well as leaching into groundwater. Results will be discussed both in context of comparison to the federal levels as well as the timeline that these regulations started coming into play.