DULUTH – A swath of the St. Louis River once teeming with toxic waste is now healthy enough for swimming.

The U.S. Environmental Protection Agency (EPA) and U.S. Steel joined state and city officials Wednesday to celebrate the opening of a new waterfront recreation area in western Duluth's Morgan Park. It was once the site of Duluth Works, U.S. Steel's coking and mill operation.

The Superfund site that was closed to the public for decades has been transformed into acres of rolling green space with a new, walkable peninsula, a 2-mile extension of the Waabizheshikana Trail and safe habitat for both aquatic life and woodland creatures.

The $186 million cleanup and restoration of the Spirit Lake portion of the Lake Superior estuary — where chemicals and heavy metals were dumped for 50 years — took four years to complete.

"The Spirit Lake cleanup is the largest, most complex project conducted under the Great Lakes Legacy Act," said Debra Shore, the EPA's Midwestern office leader. "This is an exciting day, a happy day, for everyone who loves the St. Louis River."

The Legacy Act provides federal funding to clean polluted waterways known as Areas of Concern in the Great Lakes. Federal, state, tribal and local efforts to clean the St. Louis River and remove it from the national list of waterways have been ongoing for more than 30 years. In 2022, the EPA announced $113 million for three highly contaminated sites in the river, including the Spirit Lake area. Through a private/public partnership, U.S. Steel was responsible for 51% of the Duluth Works project, with federal funds covering the rest. The city has also invested in recreational improvements along the river.

Shore said more than 60% of the work needing completion to delist the river is done, putting it on track to be removed from the list by 2030.

In Spirit Lake, workers remediated more than 1.3 million cubic yards of material, leaving nearly 140 acres of cleaned riverbed. The area holds a shallow sheltered bay for fish and is now home to more than 360,000 aquatic plants.

The waterfront, which runs along the Lake Superior & Mississippi tourist railroad, will eventually be filled by native marshes. The ecosystem is now healthy enough for swimming, boating and fishing, said the Minnesota Pollution Control Agency's Peter Tester.

The agency, together with the state Health Department, will recommend that the area's swimming restrictions be lifted, he said.

The St. Louis River spans the ancestral lands of the Fond du Lac Band of Lake Superior Chippewa. A haven for migratory birds and spawning grounds for lake sturgeon and other fish, it was designated a National Water Trail in 2020.