On March 12, 2024, the Pennsylvania Environmental Quality Board (EQB) approved the Pennsylvania Department of Environmental Protection’s (PADEP) proposal to amend the Land Recycling and Remediation Standards Act regulations under Chapter 250 of the Pennsylvania Code. Included in the rulemaking are cleanup standards for select new Per- and Polyfluoroalkyl substances (PFAS): Gen-X (Hexafluoropropylene Oxide (HFPO) Dimer Acid) and its ammonium salt; Perfluorobutanoic acid (PFBA); Perfluorohexanoic acid (PFHxA); and the potassium salt of Perfluorobutane sulfonate (PFBS). The proposed rulemaking also includes revisions to the soil and groundwater standards for Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA). Although the proposed rulemaking has not yet been published in the Pennsylvania Bulletin, PADEP is recommending a 60-day public comment period and three public hearings.
The proposed cleanup standards – “medium specific concentrations” (MSCs) – for these new PFAS compounds are as follows:
| Substance | Soil (mg/kg) | Groundwater (µg/L) |
| Hexafluoropropylene Oxide (HFPO) Dimer Acid (Gen-X) | 0.66 (residential) 9.6 (non-residential) | 0.01 |
| Hexafluoropropylene Oxide (HFPO) Dimer Acid Ammonium Salt (Gen-X) | 0.66 (residential) 9.6 (non-residential) | 0.01 |
| Perfluorobutanoic Acid (PFBA) | 220 (residential) 3,200 (non-residential) | 35 residential) 97 (non-residential) |
| Perfluorohexanoic Acid (PFHxA) | 110 (residential) 1,600 (non-residential) | 17 (residential) 49 (non-residential) |
| Potassium perfluorobutane sulfonate (PFBS) | 66 (residential) 960 (non-residential) | 2 |
| Perfluorooctane Sulfonate (PFOS) | Proposed revisions from 4.4 to 0.68 (residential) and 64 to 9.9 (non-residential) | Proposed revision from 0.07 µg/L to 0.018 µg/L to reflect the PA PFOS MCL |
| Perfluorooctanoic Acid (PFOA) | Proposed revisions from 4.4 to 0.86 (residential) and 64 to 12 (non-residential) | Proposed revision from 0.07 µg/L to 0.014 µg/L to reflect the PA PFOA MCL |
As indicated in the above table, PADEP is also proposing to revise the Act 2 groundwater standards for PFOS and PFOA to reflect the Maximum Contaminant Levels (MCLs) under the Pennsylvania Safe Drinking Water Act regulations for those compounds at 25 Pa. Code Chapter 109, which were finalized and became effective on January 14, 2023. The Chapter 250 regulations already incorporate Chapter 109 MCLs by reference, so this change appears to be a formality.
In addition to the new proposed PFAS compounds, PADEP’s proposed rulemaking also seeks to clarify that only “final” versions of MCLs and Health Advisory Levels (HALs) are incorporated as cleanup standards under 25 Pa. Code 250.304(c). That regulation currently provides that MSCs include Lifetime Health Advisory Levels set forth in Health Advisories by EPA but does not address the effect of an “interim” HAL. This proposal is likely to clarify the effect of EPA’s June 2022 interim HALs for PFOA and PFOS on Act 2 cleanup standards.
For more information on PADEP’s proposed Act 2 rulemaking, see the following documents: