MADISON, Wis. (AP) — A federal judge has approved a settlement calling for polluters to cover remaining costs of cleaning up the Fox River and Green Bay.

U.S. District Judge William Griesbach approved the settlement Thursday.

Paper companies discharged polychlorinated biphenyls, or PCBs, into the Fox River and Green Bay from the mid-1950s until 1971. Cleanup began in 1998 and is expected to finish next year. Remaining costs are expected to top $1.2 billion.

State and federal officials sued 10 paper companies and two municipalities in 2010, demanding they pay for cleanup. NCR Corporation, P.H. Glatfelter Company and Georgia-Pacific Consumer Products LP and other responsible parties have already paid for much of the cleanup under previous settlements in the case.

The latest settlement calls for NCR, Glatfelter and Georgia-Pacific to cover remaining costs.