MINNEAPOLIS (AP) - Two lawsuits are seeking to overturn the U.S. Environmental Protection Agency's decision to grant a water quality variance to the Mesabi Nugget iron processing plant near Hoyt Lakes, saying regulators violated the Clean Water Act and other federal laws when they approved it late last year.

The lawsuits were filed late Monday by the environmental group WaterLegacy and by the Fond du Lac and Grand Portage Chippewa bands.

They say the variance improperly allows the plant to discharge excessive levels of contaminants.

And they say the EPA's decision threatens wild rice and other aquatic organisms in the St. Louis River and two of its tributaries.

EPA spokeswoman Phillippa Cannon says the agency does not comment on pending litigation.

Mesabi Nugget did not immediately respond to messages seeking comment.