GREEN BAY, WI (WTAQ) - The federal government will ask Judge William Griesbach Thursday to order the resumption of a major cleanup of the Fox River.

Earlier this week, Griesbach absolved Appleton Papers of any more financial liability in the cleanup, after the firm had paid about one-fifth of the estimated billion-dollar cleanup cost. NCR and about 10 other paper firms remain liable for the massive cleanup.

It was halted a year ago when Appleton and NCR refused to pay $50 million more for dredging work and the removal of PCB’s. Those cancer-causing chemicals were placed in the Fox River by paper firms in the 1950’s and ‘60’s.

The Green Bay Press-Gazette notes that Appleton Papers still has indirectly liability for the cleanup, as the result of an arbitration agreement in New York.