Tetra Tech Ec, Inc. and Lower Fox River Remediation LLC, Petitioners-Appellants-Petitioners v. Wisconsin Department…

Summary

The supreme court affirmed the court of appeals, holding that the term 'processing' in Wis. Stat. § 77.52(2)(a)11. includes the separation of Fox River sediment into its component parts, so the petitioners' remediation services were subject to sales and use taxes. A majority also ended Wisconsin's practice of deferring to administrative agencies' conclusions of law, announcing de novo review of agency legal conclusions with 'due weight' given to agency expertise as a matter of persuasion under Wis. Stat. § 227.57(10), though the lead opinion's constitutional rationale — that deference cedes core judicial power in violation of Wis. Const. art. VII, § 2 — drew only two votes. Justice Ziegler, joined in Part I by Chief Justice Roggensack, and Justice Gableman, joined by the Chief Justice, concurred on judicial-administration and constitutional-avoidance grounds respectively. Justice Ann Walsh Bradley, joined by Justice Abrahamson, concurred in the mandate but argued the court ignored controlling precedent and destabilized decades of deference-based decisions.