On Tuesday, March 14, EPA released pre-publication proposed Maximum Contaminant Limits (MCLs) for six specific per- or poly-fluoroalkyl substances (PFAS), also referred to colloquially as “forever chemicals” and “emerging contaminants.” The proposed regulatory limits were long-anticipated, and will be open for public comment once the proposed rulemaking is published in the Federal Register. The rule proposes a National Primary Drinking Water limit on PFOA and PFOS of 4.0 parts per trillion (or nanograms per liter). It also proposes a “hazard index” approach to limit the total concentration of four additional PFAS compounds: PFNA, PFHxS, PFBS, and HFPO-DA.
As previously discussed on this blog, PFAS is a catch-all name for a broad family of compounds, now estimated to include over 9,000 unique chemicals, which were used extensively in a variety of manufacturing processes and consumer products for decades. The strong carbon-fluorine bond that is the common feature to the chemical family makes many of these chemicals ideal for various applications such as water and stain repellant treatments, but also makes the substances highly persistent in the environment. The six specific chemicals named in the EPA proposed rule include two of the most common and most studied PFAS chemicals, PFOA and PFOS, which were long used for fabric treatments and fire-fighting foams. PFOA and PFOS have also been the subject of EPA “health advisory” limits for several years. The remaining chemicals, while not as prevalent or intensely studied, have long been utilized in similar applications to PFOA and PFOS, and have been the subject of piecemeal bans or regulatory limitations in multiple jurisdictions.
The proposed limits will place enormous compliance burdens on public drinking water systems and are likely to result in higher water rates charged to consumers. Current analytical techniques are generally insufficient to detect PFAS compounds at the 4 ng/l level mandated by EPA’s proposed rule, and treatment technology that adequately treats drinking water without creating substantial waste management burdens for PFAS contaminated waste is still in its infancy. The proposed rule will be followed closely by stakeholders on all sides.
