After more than two decades of controversy and construction, the third runway at Sea-Tac International Airport is set to open for commercial airline flights on Thursday, Nov. 20.

With the delays, costs for the 150-ft-wide, 17-inch thick, 8,500-foot runway ballooned to $1.2 billion.

U.S. Secretary of Transportation Mary Peters and acting Federal Aviation Administration administrator Robert Sturgell are scheduled to fly in to join Gov. Chris Gregoire and other dignitaries for an invitation-only ceremony around 3 p.m. Nov. 20 in the Gina Marie Lindsey Arrivals Hall.

Peters and Sturgell are planning to attend two other runway openings at Dulles airport in Washington D.C. and O'Hare airport in Chicago before winging west to Sea-Tac.

The runway is designed to avoid weather delays by allowing two airplanes to land on separate runways during times of low visibility, according to Port spokesman Perry Cooper. The current two runways are 800 feet apart, meaning planes can approach in only a single stream.

Those conditions occur up to 44 percent of the time at Sea-Tac, he added.

In 2005, nearly 25 percent of all flights into Sea-Tac arrived late, according to Port officials.

Cooper noted the added runway could trim landing delays from 90 minutes down to 15 minutes, which is considered within on time arrival parameters.

Originally, the runway was designed for landings only, but Port staffers say it may be used for takeoffs in rare instances.

Cooper said the first commercial use of the runway on Thursday could be for a takeoff.

It's been a long road to Thursday's opening.

The idea of a third runway emerged in the 1980s and by the 1990s an alphabet soup of community organizations sprang up to fight the addition of another airport runway in the Highline area.

Government leaders in Burien, Normandy Park, Des Moines, Tukwila, Federal Way and the Highline School District formed the Airport Communities Coalition. The Committee Against Sea-Tac Expansion (CASE) rallied private citizens. The Regional Commission on Airport Affairs (RCAA) was another private group that fought the runway as well as speaking out on airport expansion and air transportation issues.

In 1993, neighboring cities filed a lawsuit alleging the runway environmental impact statement didn't fully take into account the impact to the communities.

The Port of Seattle, operators of the airport, started buying up homes in the Sunnydale neighborhood in 1996. The Federal Aviation Administration greenlighted the project in 1997 and was promptly sued.

The state Department of Ecology approved an environmental permit in August 2001 but the state Pollution Control Hearings Board (PCHB) granted a stay of the permit in December. The PCHB issued its decision in August 2002. Parties on both sides promptly appealed it.

In December 2002, the U.S. Corps of Engineers granted the Port's wetlands permit.

In May 2004, the state Supreme Court issued a decision upholding the State DOE permit. A U.S. Appeals court judge also upheld the Corps permit.

By June, with the last of 22 lawsuits decided, dump trucks started to roll in earnest to the runway construction site.

City leaders disbanded the ACC in September and by January of 2005, the cities were meeting with the Port in the Highline Forum to share ideas and cooperate on economic development.

Paving began in July 2007 and was completed by Thanksgiving.

An Alaska Airlines 737 was the first jet to set down on the runway as part of FAA certification tests on Sept. 25. A Northwest Airlines A330 widebody jet landed two weeks later.

Undoubtedly, the runway and its construction are a massive engineering feat.

The runway required 130,000 cubic yards of concrete and 35,000 tons of asphalt.

More than 16 million cubic yards of fill dirt went into the embankment. About 13 million cubic yards of fill dirt were trucked to the site between 2002 and 2006.

During the busiest haul period, trucks delivered material up to 20 hours a day, six days a week. On a peak day, about 1,800 deliveries were made with 58,00 tons delivered.

The airport plateau was extended 2,00 feet to the west.

The embankment required three mechanically stabilized earth walls to reduce impacts on nearby Miller Creek and wetlands. A system of storm water channels was built into the embankment as to manage storm water runoff.

There are seven construction storm water ponds and five treatment centers. Treatment is with a crab shell product called chitosan coagulant and sand filters.

Cooper reports that environmental management of Miller Creek has worked so well that salmon have been videotaped returning to the creek to spawn.