SEATTLE (AP) — A major part of the cleanup of Seattle’s Duwamish Waterway is underway.

The Boeing Co. says it has started dredging the lower Duwamish near the site of its former World War II-era airplane factory, known as Plant 2. The factory turned out B-17 bombers and was home to “Rosie the Riveter,” the women who built thousands of planes during the war.

The Environmental Protection Agency named the lower five miles of the river a Superfund site more than a decade ago.

The Duwamish was a meandering river before it was straightened and deepened into a navigation channel running through Seattle’s industrial core. Decades of industrial use left pollution that’s mixed into the mud at the river bottom and banks.

Boeing says it’s committed to restoring the natural habitat. Boeing reached a consent decree with the Justice Department over the cleanup in 2010.