Air Operating Permit Renewal 4

The Hanford Site is in southeastern Washington and formerly produced plutonium for the nation’s defense program. Today, waste management and environmental cleanup are the primary missions at Hanford. The permittee is the U.S. Department of Energy.

The proposed permit renewal and statements of basis are available for review on the NWP Public Involvement page.

Electronic copies of the proposed renewal are also located at the Administrative Record and Information Repositories. 

Ecology is extending the public comment period on the draft Renewal 4 of the Hanford Site AOP by 21 days, to September 19, 2025. It was discovered that the notification of a complete application, which was submitted with Letter 23-ECD-0094, was not posted to the Ecology Permit Register in a timely manner for WAC 173-401-805(2)(b). Ecology has posted this notification in the August 11, 2025, update of the Permit Register and is extending the comment period to ensure sufficient time for review