On May 18, 2022 EPA added five PFAS chemicals to its lists of Regional Screening Levels (RSLs) and Regional Management Removal Levels (RMLs). As background, RSLs are site-specific risk-based exposure concentrations for individual chemicals that EPA considers to be protective for humans over a lifetime. RMLs are generic non-site-specific risk-based exposure concentrations for individual chemicals that are typically higher than RSLs (and not necessarily protective for humans over a lifetime). Both RSLs and RMLs are used as benchmarks to determine whether further federal action is needed at a particular site. For example, if a site is examined for the presence of contaminants on this list and the RSLs are below those concentrations (whether in air, water, or soil), generally no further action is required. By contrast, if the contaminants are above the applicable RSLs or RMLs, further investigation may be required to assess whether removal actions might be necessary under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

Previously, EPA’s RSLs and RMLs only included one PFAS chemical: PFBS. The May 18 update adds PFOA, PFOS, PFNA, PFHxS, and HFPO-DA to these lists using fairly low levels derived from the Agency for Toxic Substances and Disease Registry’s 2021 toxicological profile (ATSDR) for the first four chemicals and a final EPA toxicity value for HFPO-DA that we discussed in our March 29, 2022 issue. And this may not be the last of EPA’s activity in this area—EPA updates these lists twice each year and has confirmed that it may add other PFAS chemicals to these lists. We’ll be sure to provide an update if, and when, any further actions are taken.