Navigating Michigan’s PFAS Regulations: From State Supreme Court Review to Impending Federal Standards

On February 2, 2024, the Michigan Supreme Court agreed to review 3M’s challenge to the State of Michigan’s rulemaking that set maximum containment levels (MCLs) for seven chemicals categorized as per- and polyfluoroalkyl substances (“PFAS”). MCLs are promulgated under Michigan’s Safe Drinking Water Act and regulate the maximum levels of hazardous contaminates that may be present in water supplied by public water systems.

The Supreme Court will review an August 2023 decision by the Court of Appeals affirming a November 2022 decision by the Michigan Court of Claims which held that the MCL rulemaking was invalid because of a deficient regulatory impact statement (“RIS”). Specifically, the Court of Claims found that the RIS did not contain the requisite estimate of the “statewide compliance costs of the proposed rule on businesses and other groups,” as required by Michigan’s Administrative Procedures Act.

Strictly speaking, the RIS did contain estimated compliance costs for the public water systems subject to the new MCLs. However, it did not consider compliance costs associated with corresponding changes to Michigan’s Part 201 cleanup standards for groundwater used for drinking water (i.e., non-public water supplies like residential well water). By operation of law under the Part 201 statute, where an MCL exists that is more stringent than the Part 201 cleanup criteria level for the same substance, the MCL becomes the Part 201 criteria level. That is exactly what happened here, where the Part 201 cleanup standards for perfluorooctanoic acid (“PFOA”) and perfluorooctanesulfonic acid (“PFOS”) were 70 parts per trillion (ppt) (individually or combined) at the time MCLs for those compounds were promulgated at eight ppt and 16 ppt, respectively. Put differently, the RIS deficiency was that it did not consider the compliance costs associated with the Part 201 standards for PFOA and PFOS decreasing to match the new MCLs for those chemicals.  

The Court of Claims stayed the effect of its decision until the parties exhausted their appellate rights and a judgment has become final. This means the PFAS MCLs have remained in effect and will continue to be in effect until, at the very least, the Supreme Court issues its decision.

Despite the legal saga surrounding 3M’s challenge of the MCLs, one should recognize that over the long run, it will likely have little impact on Michigan’s regulatory requirements for PFAS. For starters, the State could try to cure the RIS deficiency by simply developing the missing cost estimate and re-doing the rulemaking. But more likely, the issue will be largely or entirely mooted by activities related to finalization of federal MCLs for PFAS.

In March 2023, federal MCLs were proposed for six of the seven PFAS for which Michigan MCLs were promulgated. Finalization was expected by the end of 2023 but has not yet occurred. Of the six proposed federal MCLs, four of them are lower than the Michigan MCLs—with PFOA and PFOS at an exceptionally low four ppt each. Under federal law, Michigan is generally (subject to potential variances and exemptions) required to develop MCLs that are at least as stringent as the federal versions, meaning a new rulemaking will likely occur after the federal MCLs become final. The bottom line is that irrespective of the Supreme Court’s decision, eventually Michigan will likely have PFAS MCLs on the books that are at least as stringent as the federal MCLs. And because Part 201 regulates all six of the PFAS compounds for which federal MCLs have been proposed, the new MCLs will effectively become the Part 201 criteria by operation of law—if the final federal MCLs are more stringent than current Part 201 criteria.

Hence, the more significant long-run story continues to be imminent finalization of federal MCLs for PFAS that—if consistent with the proposed levels—will likely drive down Michigan MCLs and associated Part 201 criteria to exceptionally low levels for most of the PFAS currently regulated in Michigan (and especially for PFOA and PFOS).

If you have any questions about the information in this alert, please contact Todd Schebor, Paul Stewart, or your Dykema relationship attorney.