Three companies will pay $8.2 million in a settlement over pollution on the St. Louis River in the Twin Ports dating back to the first half of the 20th century, the U.S. Department of Justice announced Thursday.

XIK, Honeywell International Inc. and Domtar Inc. reached a settlement with the federal government and the states of Minnesota and Wisconsin for natural resource damages at the St. Louis River, Interlake and Duluth Tar Superfund site, which covers 255 acres and includes Stryker Bay in West Duluth. The three companies previously paid about $80 million to clean up the Superfund site under prior agreements with the Minnesota Pollution Control Agency; that cleanup began in 2006 and wrapped up in 2011.

A complaint, filed simultaneously in court with the settlement on Thursday, claims that XIK, formerly known as Interlake Corp., Honeywell, formerly known as Allied Signal, and Domtar are liable for industrial discharges of polycyclic aromatic hydrocarbons (PAHs) at the Superfund site during the first half of the 20th century, according to the the Justice Department.

A consent decree filed Thursday, outlining the settlement, was signed by representatives of the federal and state governments, the Fond du Lac Band of Lake Superior Chippewa, the 1854 Treaty Authority and the three companies. Under the terms of the decree, the companies agree to pay the $8.2 million but do not admit liability.

Chemicals identified as PAHs can cause fish to develop tumors and can be toxic for other aquatic life. Humans exposed to PAHs potentially face increased cancer risks. PAHs were found in river sediments throughout the site in concentrations that cause injury to natural resources, including vegetation, fish and birds, according to the Justice Department.

"The restoration work enabled by this settlement will make significant contributions to the environment in the area of the St. Louis River and nearby Lake Superior," said acting Assistant Attorney General Jeffrey H. Wood of the Justice Department's Environment and Natural Resources Division.

The settlement includes $6.5 million to be used on restoration activities along the river. A proposed restoration plan released Thursday - available for review and comment for 30 days at www.pca.state.mn.us/waste/st-louis-river-interlakeduluth-tar-site - recommends these projects:

Kingsbury Bay: restoration of a 70-acre shallow, sheltered bay habitat that will add recreational access areas for fishing and a boat launch, improve habitat and reduce invasive vegetation.

Kingsbury Creek watershed: activities to reduce sediment accumulation, improve water quality and support the shallow sheltered bay habitat of the restored Kingsbury Bay.

Wild rice restoration: enhancement of wild rice stands within the St. Louis River estuary.

Cultural education opportunities: development of informational displays to communicate the importance of the St. Louis River estuary's cultural and natural resources.

The MPCA began working on the site in 1979, and the site was on the Superfund list beginning in 1983. Stryker Bay and Slips 6 and 7 were heavily polluted from the late 1800s to the 1960s; the harbor area was ringed with tar and coke plants, heavy industry and slaughterhouses that all discharged industrial waste directly into the water. Coal tar in some areas was 13 feet thick under the water.

The work from 2006 to 2011 dredged and mostly capped tons of contaminants left behind by heavy industry of past decades.