BANGOR – An environmental group expressed disappointment Wednesday at a federal judge’s dismissal of its clean water lawsuit against International Paper Co.

The Natural Resources Council of Maine and the Natural Resources Defense Council had alleged that IP’s wastewater polluted the Androscoggin River below its Jay mill in violation of state and federal water-quality standards.

U.S. District Judge John Woodcock disagreed Tuesday, saying the company operated with proper permitting.

The lawsuit asserted that Maine and federal laws require the mill to have a permit to discharge polluted wastewater into the river, but IP has not had one for two decades. The plaintiffs said the last valid permit issued to the company was in 1985, and it was valid for only one year.

Woodcock said the 1985 permit remained effective until a new one was issued in September 2005.

The judge wrote in his decision that that NRCM “failed to give proper notice of some legal theories … its request for an injunction is moot, and that in any event [the Environmental Protection Agency’s] 1985 permit remained effective until the Maine Department of Environmental Protection issued a new permit in 2005.”

The Natural Resources Council said Wednesday that Woodcock’s decision was based on administrative technicalities.

“Although IP prevailed in court on a technicality, the court did not say the company has done enough to clean up the Androscoggin River,” said the council’s executive director, Brownie Carson.