"A proposed cleanup of Montana air pollution would force three industrial plants to spend $90 million on measures to improve visibility in some of the nation's prized public lands, including Yellowstone and Theodore Roosevelt National Parks."
"The Environmental Protection Agency plan would clear the air in the Big Sky State of about 15,000 tons annually of sulfur dioxide and nitrogen oxides. Those pollutants react with the atmosphere to create haze.
The agency says upgrades would be needed within five years at the Colstrip coal power plant, Ash Grove cement plant near Montana City and Holcim cement plant near Three Forks.
Colstrip would bear the brunt of the cost -- more than $80 million for new scrubbers and other steps to clean the emissions from its stacks."