Port of Seattle approves a Supplemental Environmental Impact Statement and permit applications for third runway construction at Sea-Tac International Airport on May 27, 1997.

  • By Paula Becker (with research by Daryl McClary and Walt Crowley)
  • Posted 3/21/2003
  • HistoryLink.org Essay 4207
See Additional Media

On May 27, 1997, the Port of Seattle adopts Resolution 3245, approving the Supplemental Environmental Impact Statement prepared by the Port and the Federal Aviation Administration. The Resolution also authorizes construction of a third runway for Seattle-Tacoma (Sea-Tac) International Airport pending approval of necessary permits.

The year before, on February 1, 1996, the Port and the FAA had finalized an earlier Environmental Impact Statement for the third runway project. But when it became apparent that the enormous growth of the Puget Sound region during the mid-1990s might render obsolete the facts and figures considered in this earlier Environmental Impact Statement, the FAA and Port undertook a Supplemental Environmental Impact Statement with updated figures. The Final Supplemental Environmental Impact Statement addressed comments, both oral and written, that had been taken on the draft statement. It reaffirmed that there were no significant construction or operational impacts on the environment, buildings, or people that could not be mitigated by the procedures the Port planned to use.

Long Road Behind and Ahead

Planning for a third runway for Sea-Tac International Airport began in 1988 when the Port of Seattle published a long-term study of the air traffic future of the Seattle-Tacoma region. This study, called the “Comprehensive Planning Review and Airspace Update Study,” predicted that the airport would reach its maximum efficient capacity as early as 2000. This forecast triggered a comprehensive “Flight Plan” study sponsored by the Port and the Puget Sound Regional Council and guided by an independent Puget Sound Air Transportation Committee between 1989 and 1992.

By May 1997, citizens of the Puget Sound region had participated in this public process for 11 years. Numerous studies were completed and experts empanelled, and the Port of Seattle and the FAA prepared a 5,500 page Environmental Impact Statement that concluded that all possible environmental impacts possibly arising from runway construction and operation could be mitigated. Resolution 3245 also approved the additional noise-reduction measures mandated by Puget Sound Regional Council Resolution A-96-02 in July 1996.

The Port of Seattle’s adoption of Resolution 3245 and the FAA’s final “record of decision” on July 3, 1997, marked the end of 11 years of study, regional planning, and environmental assessments leading up to the third runway. The next steps would include detailed project planning, engineering, and application for essential “401” and “404” environmental permits from the Washington State Department of Ecology and U.S. Army Corps of Engineers respectively, with ample opportunity for public comment and potential administrative and legal appeals.

Construction activity began in 1997, but was halted several times by litigation. The last appeals of the necessary environmental permits were exhausted in August 2004. The third runway was completed in 2008 at a cost of just over $1 billion.


Port of Seattle Resolution 3245, May 27, 1997; “Regional Air Capacity – Public Involvement History,” Port of Seattle memorandum, July 29, 2002; “Detailed History of the Third Runway Planning Process,” Port of Seattle memorandum, October 3, 2002; “Federal Register Environmental Documents,” United States Environmental Protection Agency Website (www.epa.gov/fedrgstr/EPA-MPACT/1996/December/Day-27/pr-17278.html); The Seattle Times, July 4, 1997; Larry Lange and Jeffrey M. Barker, "You Know That Third Runway? Sea-Tac's Really Getting It," Seattle Post-Intelligencer, August 20, 2004, p. A-1.
Note: This essay was updated on August 31, 2004, and again on December 5, 2008.

Licensing: This essay is licensed under a Creative Commons license that encourages reproduction with attribution. Credit should be given to both HistoryLink.org and to the author, and sources must be included with any reproduction. Click the icon for more info. Please note that this Creative Commons license applies to text only, and not to images. For more information regarding individual photos or images, please contact the source noted in the image credit.
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License
Major Support for HistoryLink.org Provided By: The State of Washington | Patsy Bullitt Collins | Paul G. Allen Family Foundation | Museum Of History & Industry | 4Culture (King County Lodging Tax Revenue) | City of Seattle | City of Bellevue | City of Tacoma | King County | The Peach Foundation | Microsoft Corporation, Other Public and Private Sponsors and Visitors Like You