"BILLINGS, Mont. -- Environmental groups filed a federal lawsuit Wednesday against the owners of Montana's massive Colstrip coal-fired power plant, seeking to force the installation of more pollution controls at the decades-old facility."

"The Montana Environmental Information Center and Sierra Club also asked the U.S. District Court in Billings to issue penalties for alleged emissions violations.

The center's Anne Hedges said the penalties could total many millions of dollars for violations over 20 years."

Matthew Brown reports for the Associated Press March 6, 2013. [2]