Chapter 173-424 WAC and WAC 173-455-150 - Clean Fuels Program Rule and Clean Fuels Program Fees
The Washington State Department of Ecology (Ecology) is initiating a rulemaking process to amend Chapter 173-424 WAC, Clean Fuels Program Rule and Section 150 of Chapter 173-455 WAC, clean fuels program fees. The clean fuels program reduces life-cycle greenhouse gas emissions, known as carbon intensity, of transportation fuels in Washington.
This rulemaking will update the Clean Fuel Standard (CFS) to implement Second Substitute House Bill 1409 (SSHB 1409), which was signed into law on May 17, 2025. This legislation updates carbon intensity reduction targets for years 2028 through 2038. Now, the CFS will reduce the life cycle greenhouse gas emissions from transportation fuels by 45% below 2017 levels by 2038, with the option to reduce as much as 55% by 2038 if certain conditions are met. To meet the new cumulative carbon-intensity reduction target, the law directs Ecology to implement annual reduction limits between three and four percent for years 2028 to 2038.
During this rulemaking Ecology will also update the program’s primary carbon intensity determination tool, the WA-GREET model to WA-GREET 4.0. This will ensure the use of the most up-to-date scientific methodology and make other technical improvements to support policy implementation, such as aligning with other low carbon fuel programs per RCW 70A.535.060. This rulemaking will also consider other technical amendments necessary to improve implementation of the rule, the fee structure, and integrity of the greenhouse gas emissions reductions credited in the program. Transportation is Washington’s largest source of greenhouse gas emissions. Reducing the carbon intensity of this sector will increase availability of low carbon transportation fuel in Washington, in turn reducing greenhouse gas emissions from entering the atmosphere and improving air quality.
Rulemaking timeline
Announcement phase (CR-101)
Filing date:
Jan. 20, 2026
Announcement documents
Rule development phase
Jan. 20, 2026 - Spring 2027Public input & involvement
Public comment period
January 20, 2026, at 12 a.m. – March 3, 2026, 11:59 p.m.
Submit comments online to provide feedback on the Clean Fuels Program Rule and Clean Fuels Program Fees.
Accessibility
To request ADA accommodation for disabilities, or printed materials in a format for the visually impaired, contact Ecology's ADA Coordinator by email at ecyadacoordinator@ecy.wa.gov, or call 360-407-6831. People with impaired hearing may call Washington Relay Service at 711. People with speech disability may call TTY at 877-833-6341.