The Biden administration is siding with the city of South Portland over an air quality dispute with a pipeline company.

According to the Portland Press Herald, a brief filed by the U.S. Department of Justice concluded that federal law doesn’t preempt South Portland’s Clear Skies Ordinance.

The ordinance would prevent the company that owns the pipeline from exporting crude oil from Canada using tankers on the city’s waterfront. It brings the city one step closer to winning a 6-year legal battle over the issue.

Environmentalists say the brief could also set a precedent for other towns and cities across the country that are involved in similar disputes.