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Air Quality Program

A photograph of factory with many stacks.

Prevention of Significant Deterioration (PSD) Permit Information

Prevention of Significant Deterioration (PSD) permits are for projects that may significantly increase air pollution. Ecology prepares PSD permits for industrial sources of air pollution, except for projects involving Washington's Energy Facility Site Evaluation Council (EFSEC).

This web page includes information about PSD permits that are being or have been drafted by Ecology, comment and appeal procedures, and information for PSD permit applicants.

The permitting process is as follows:

  • The owner or operator of the facility meets with Ecology and others to discuss what to include in the application about methodologies for dispersion modeling and how to determine what Best Available Control Technology (BACT) to use to minimize pollutant emissions.
  • The applicant submits an application that contains all the necessary technical information to determine:
    • the level of control technology and emission limitations constitute BACT; and
    • that the pollutant emissions will not significantly impact the environment.
  • Ecology drafts a permit that satisfies all regulatory requirements.
  • Ecology releases the draft permit and a fact sheet for a minimum 30-day public comment period. These documents are posted on the draft and final PSD permits page.
  • After the public comment period, Ecology:
    • makes changes to the draft permit in response to public comment;
    • writes a responsiveness summary of the public comments; and
    • issues a final permit.
    The final permit and responsiveness summary are posted on the draft and final PSD permits page.

Other information

Certain electric power generation projects are under the authority of Washington's Energy Facility Site Evaluation Council (EFSEC).  Contact EFSEC for more information.

Related Links

Contact Us


Application for a Prevention of Significant Deterioration Applicability Determination

Governor's Office for Regulatory Innovation and Assistance (ORIA)
(external link)