The Department of Ecology last week imposed yet another fine on the Port of Seattle. This time the port was fined $20,000 for releasing untreated storm water from aircraft preparation and taxiing areas at Sea-Tac International Airport into Des Moines Creek in 2005.

The port may appeal the penalty to Ecology or the Washington State Pollution Control Hearings Board within 30 days.

Between two and 2.7 million gallons of water that should have flowed to the airport's industrial wastewater treatment plant entered the creek because of improper valve settings on Nov. 25,.

The storm water -- from taxi strips and aircraft parking areas -- contains oil, grease and de-icing compounds that drip from the planes.

"Sea-Tac has a well-designed industrial treatment system that needs careful and attentive management to work well," said Kevin Fitzpatrick, Ecology's regional water quality program supervisor.

"Because of this incident the airport has acted to improve the system's management and oversight and to respond to problems rapidly."

The penalty results from violations identified in a related Ecology order, issued Jan. 10. That order directed the airport to review the oversight, operation and maintenance of the treatment system and an upgrade project that is under way.

A report -- with recommended improvements -- is due within 45 days.

"Stewardship of our precious environment is the highest priority for the Port of Seattle," said Port of Seattle commission chairwoman Patricia Davis.

"We have already asked our staff to intensify prevention, oversight, training, and compliance on all our projects."