Lawsuit filed over data center pollution permit

The Sierra Club on Friday filed a lawsuit against the Wisconsin Department of Natural Resources alleging that the agency did not require a needed environmental impact statement before approving an air pollution control permit for the Vantage Data Centers Lighthouse Campus in Port Washington.

The agency’s environmental review of the project has been inadequate, the suit states, and it asks the court to reverse the DNR’s decision not to require an environmental impact statement, or EIS, and to block the permit until the agency does so.

The lawsuit is just the latest in a series of challenges to the data center project, which has proven controversial not just in Ozaukee County but throughout the state since it was announced last year.

This suit was filed by Midwest Environmental Advocates on behalf of the Sierra Club, which describes itself as “the largest and most influential grassroots environmental organization in the country.”

Since the Vantage data center campus was announced, individuals and environmental groups have repeatedly asked for an EIS for the project.

According to the Sierra Club lawsuit, the DNR initially said it would require an EIS for the Vantage project but later backpedaled.

The lawsuit notes that the data center campus required multiple approvals and permits from the DNR, adding that Vantage submitted an application for an air pollution control construction permit and an initial operation permit for air emission sources in August 2025.

In a July 18, 2025, email, a Vantage attorney described the DNR as being “crystal clear” that an EIS was required due to the “scope and scale” of the data center campus, the lawsuit states.

Vantage, it adds, believed “that study of the environmental impacts of its data center was a threat to the project moving forward.”

The lawsuit quotes a text from a Vantage representative to Port Mayor Ted Neitzke in September 2025 that an EIS would “kill the project,” and Neitzke’s response that he would meet with the secretary of the DNR days later.

In December, the lawsuit states, the DNR posted a less-detailed review called an environmental analysis summary on its webpage. The analysis resembled an environmental assessment, which the suit notes does not take the place of an EIS, and the DNR did not hold a public comment period or public hearing on the document.

The analysis does not consider many aspects of the data center, the lawsuit states, including the impact on recreational resources, climate change impacts of additional power plants required to provide electricity for the campus and whether the project is compatible with the state’s clean energy and greenhouse gas reduction goals.

It also fails to study, develop and describe appropriate alternatives that could mitigate or avoid some or all of the adverse environmental impacts, the lawsuit states.

Yet two days later after the analysis was posted, the lawsuit states, the DNR said it had satisfied the environmental requirements under the Wisconsin Environmental Policy Act.

It neither prepared a draft EIS nor held a public hearing on whether an EIS should be prepared for the project, the lawsuit notes.

The lawsuit says that the state’s environmental policy act requires a “detailed” EIS for “major actions significantly affecting the quality of the human environment.”

The EIS must evaluate the entire project, including direct, indirect, secondary and cumulative impacts, it adds.

The Vantage data center meets the requirements for an EIS, the suit states, noting it is one of the first hyperscale centers in Wisconsin, consists of four data center buildings on 672 acres, will require more than 1.3 gigawatts of power — “more than all the households in Milwaukee County combined” — and will require new high-voltage transmission lines in five counties and a new gas-fueled power plant in Walworth County.

The lawsuit alleges that the data center campus will increase greenhouse gas emissions in the state by as much as 1.7% annually and worsen climate change.

Just operating the 45 diesel-fueled backup generators on the campus will emit hazardous pollutants that are deleterious to health and the environment, the suit states.

The campus will also have a negative impact on wildlife and recreation, according to the lawsuit.

The suit also noted that the Wisconsin Public Service Commission, which regulates transmission lines, has determined the project to be “a major action significantly affecting the human environment and prepared an EIS.”

The lawsuit references a former teacher who has had a lung condition and a doctoral candidate with a congenital heart condition who are concerned about the impact on their health. They fear the data center and its infrastructure will make poor air quality days more frequent and harmful, it adds.

Vantage’s data center is a “precedent-setting” action, according to the lawsuit.

The lawsuit also notes that the DNR released a draft air pollution control permit in February 2026 and made a preliminary determination it satisfied the agency’s criteria.

A public comment period and hearing drew hundreds of comments, including some from the Sierra Club, but the permit was issued on June 12.

That same day, the DNR released an environmental analysis supplement, which it said offered clarifications and additional analysis in response to comments received.

The lawsuit has been assigned to Ozaukee County Circuit Judge Steve Cain. No hearing dates have been set.