DTE will argue its $100 million Zug Island pollution fine before a federal appeals court on December 17

The biggest Clean Air Act penalty ever handed to a single facility now has a hearing date.

The fine falls on EES Coke Battery, a coke plant on Zug Island in River Rouge, just downriver from Detroit. The plant produces coke, a raw material in the steelmaking process. The order followed a September 2025 bench trial. The City of River Rouge and the Sierra Club had joined the case as intervenor plaintiffs.

An EPA engineer testified that EES Coke Battery emitted 14,180 tons of excess sulfur dioxide from 2019 to 2023, and would keep emitting about 3,000 tons a year until desulfurization is installed. The excess traces back to a 2014 state permit that removed the plant's coke oven gas combustion limit. When U.S. Steel pulled back on buying that gas in 2016, the plant flared it instead.

DTE says it will keep running the plant by the book while it appeals. The judge read the company's role differently, writing that the facility "cannot function without the DTE defendants exercising control."

The underlying case, United States v. EES Coke Battery, LLC, Case 2:22-cv-11191, sits on the public docket for the Eastern District of Michigan through GovInfo.