 Environmental Protection Agency and the U.S. Justice Department say they've reached a settlement with Marathon Oil over violations of the Clean Air Act. The agency say in a statement released Thursday that Marathon's operations in the Fort Berthold Indian Reservation resulted in thousands of tons of illegal pollution. They also claim greenhouse gases such as methane were released in large quantities contributing to climate change. The settlement requires Marathon Oil to invest more than $175 million in compliance measures that will be implemented by the end of the year.