ST. LOUIS (AP) — A federal appeals court has upheld a ruling ordering Ameren Missouri to install pollution control equipment at a coal-fired power plant near St. Louis. The decision could prompt the St. Louis-based utility to spend hundreds of millions on the 1970s-era Rush Island coal plant in Jefferson County or reevaluate its long-term power generation plans. If the utility does install the pollution control equipment, customers could see higher rates. But the U.S. Court of Appeals for the Eighth Circuit did throw out part of the previous ruling that called for Ameren to install pollution controls at a different coal plant.