"BILLINGS, Mont. -- Environmentalists filed notice Wednesday that they plan to sue the six companies that co-own eastern Montana's Colstrip power plant over alleged pollution violations."
"The Sierra Club and Montana Environmental Information Center say the plant's owners failed to upgrade pollution control equipment as required under the Clean Air Act for older power generation facilities that undergo significant changes.
Colstrip is the second largest coal-fired power plant west of the Mississippi River, burning over 10 million tons of the fuel a year to generate about 2,200 megawatts of electricity.
That power is distributed on high-voltage transmission lines to customers in Montana, Oregon and Washington state."