Wisconsin high court questions whether DNR must adopt formal rules to regulate PFAS under spills law

The Wisconsin Supreme Court heard extended arguments over whether the Wisconsin Department of Natural Resources must adopt formal rules before treating per- and polyfluoroalkyl substances (PFAS) as hazardous substances under the state spills law, case number 22 AP 718, during oral argument before the court in Madison.

The question matters because it determines whether the DNR's statements on its website and in correspondence — and an interim interpretation used in cleanup and the Voluntary Party Liability Exemption (VPLE) program — are valid agency action that must be promulgated as rules under Wis. Stat. §227.10, or whether they remain guidance the agency can use to enforce the statute without formal rulemaking.

Attorneys for the agency and for Wisconsin Manufacturers and Commerce (WMC) framed opposing legal paths. Attorney Roth, who argued for the position that agency explanations can be guidance rather than rules, told the court that “for nearly 50 years, DNR and tens of thousands of Wisconsinites have successfully used the spill law to protect our environment and public health,” and that the spills law’s broad statutory language requires agencies to apply general standards to new factual developments rather than pause enforcement until rules are adopted. Roth argued that many prior cases addressing unpromulgated rules remanded to agencies rather…