ST. LOUIS (AP) -- A federal appeals court has handed a planned coal-fired power plant in southern Illinois another legal setback, siding with a judge who halted construction until developers get a new air permit with stricter pollution controls.

It was not immediately clear whether the developers, now known as Franklin County Power of Illinois LLC, would appeal Monday's ruling by the three-judge panel with the Chicago-based U.S. 7th U.S. Circuit Court of Appeals.

The Associated Press left a message Tuesday with one of the firm's attorneys, seeking comment about whether the company might take the matter to the full 7th U.S. Circuit Court or perhaps the U.S. Supreme Court.

The Sierra Club sued developers -- then known as EnviroPower -- in May 2005, arguing that the project lacked a valid air permit for a 600-megawatt plant near Benton that would burn one million tons of coal annually and also burn mine waste as fuel.

The Illinois Environmental Protection Agency issued EnviroPower a permit in July 2001 that required the company to begin construction within 18 months and maintain continuous work at the site. Although the company failed to meet those guidelines and the permit expired, the lawsuit alleged, EnviroPower announced in late 2004 it would begin building without getting a new, updated permit with more stringent pollution controls.

The Sierra Club says it sued after EnviroPower failed to reply to its written requests to get the updated air permit.

In October 2006, U.S. District Judge Phil Gilbert issued a summary judgment for the environmental group.

In Monday's 35-page ruling, Judge Ann Claire Williams, writing for the three-judge panel, ruled that "time limits prevent companies from sitting on (such air permits) for an unreasonably long period of time."

"Presumably these requirements help ensure that major emitting facilities comply with up-to-date emissions regulations and do not construct today's facilities with yesterday's technology," Williams wrote. "Because EPA regulations require the company to obtain such a permit before it can build the facility, the court's decision leaves the company no option but to obtain this permit before it can commence construction."

Williams said she found no need to send the case back to Gilbert's court for reconsideration, ruling that "a remand on this issue would merely prolong the case, result in additional costs and not change the outcome."

The Sierra Club on Tuesday cheered the Chicago appellate court's ruling in their favor, claiming in a statement that it "effectively ends EnviroPower's seven-year effort to build the plant without modern pollution controls."

"Today is a great victory for clean air and clean energy," the Sierra Club's Verena Owen said. "We can all breathe a little easier and get to work building the clean energy future that will put us on the path to real economic recovery."

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