Chapter 173-424 WAC – Clean Fuels Program
Ecology proposes updates Chapter 173-424 WAC, Clean Fuels Program Rule. The rule aims to reduce the carbon emissions from transportation fuels used in Washington.
The rulemaking proposal promotes the production and use of alternative jet fuels, also known as sustainable aviation fuels, in Washington. These non-petroleum fuels can power airplanes while producing fewer carbon emissions. Sustainable aviation fuels can also reduce air pollution. The proposal would also strengthen incentives for investing in charging equipment for zero-emission heavy-duty trucks—a key part of Washington’s climate strategy.
Ecology is also considering other changes based on learnings from the program’s first two years, best practices used in other states, and input from groups that have expressed interest in the policy. Read the full list of changes we are considering.
This rulemaking is separate from the changes to the Clean Fuel Standard set under House Bill 1409, which will strengthen the program’s carbon intensity requirements. Passed during the 2025 legislative session, the new law requires a 45% reduction in carbon intensity by 2038, up from the previous requirement of 20%. The annual reduction in carbon intensity for 2026 and 2027 is set in statute, and Ecology expects to announce a rulemaking to incorporate targets for 2028 onward into the regulations later this year.
Rulemaking timeline
Announcement phase (CR-101)
Filing date:
Dec. 18, 2023
Announcement documents
Rule development phase
Dec. 18, 2023 – Fall 2024Public input & involvement
Draft rule language
Below are the most updated drafts of the rule language, released Nov. 26, 2024:
- November 2024 CFS draft rule language
- November 2024 rule changes summary (updated Dec. 4, 2024, with corrections)
The following links contain the initial draft rule updates, released Aug. 29, 2024:
Fourth public comment period (informal)
Nov. 26, 2024 – Dec. 13, 2024
Third public comment period (informal)
Aug. 29, 2024 – Oct. 3, 2024
Second public comment period
April 25, 2024 – June 7, 2024
First public comment period (informal)
Feb. 15, 2024 – March 24, 2024
Ecology's public meetings
| Date | Documents | Location |
|---|---|---|
| Thursday Feb. 22, 2024 1 p.m. – 3 p.m. |
||
| Wednesday Feb. 28, 2024 1 p.m. – 3 p.m. |
Agenda Presentation |
Webinar recording 1 |
| Thursday May 2, 2024 1 p.m. – 3 p.m. |
Presentation | Webinar recording 1 |
| Wednesday May 8, 2024 10 a.m. – noon |
Presentation | Webinar recording 1 |
|
Wednesday |
Presentation | Listening session recording |
|
Monday |
Presentation | Webinar recording |
| Tuesday Sept. 12, 2024 10 a.m. – noon |
Presentation | Webinar recording |
| Thursday Sept. 26, 2024 1 p.m. – 3 p.m. |
Presentation | Webinar recording |
| Thursday Dec. 5, 2024 2 p.m. – 4 p.m. |
Presentation | Webinar recording |
| Wednesday Dec. 11, 2024 10 a.m. – noon |
Presentation | Webinar recording* |
* Ecology inadvertently began recording this webinar late and missed the opening slides of the presentation. The Dec. 5, 2024, recording linked above covers the same content and includes full information on the rulemaking timeline and updates to avoided methane crediting.
1 Webinar information:
Register for each webinar to get your meeting ID and passcode.
To hear the webinar better or to call in only, use your phone (instead of the computer) to call 253‑215‑8782.
Proposed changes
This rulemaking may consider the following changes to strengthen or streamline the Clean Fuel Standard program:
- Update the deadline at which we must accept sustainable aviation fuel pathways for Clean Fuel Standard credit generation from Oct. 1, 2024, to Dec. 31, 2023.
- Establish requirements for a third-party verification program for fuel pathway applications and data reports submitted by market participants.
- Update requirements to further encourage the production of low carbon intensity sustainable aviation fuels.
- Amend or refine the compliance and enforcement process for the Clean Fuel Standard.
- Update the rule language to:
- Improve clarity and readability
- Align the rule with guidance documents
- Correct errors
- Make miscellaneous improvements to program implementation
- Update book-and-claim accounting requirements for electricity and biomethane.
- Align the rule with Oregon and/or California low carbon or clean fuel program requirements.
We are not considering changing other main components of the program, including:
- Annual carbon intensity standards
- Tier 2 WA-GREET model
- Land use change factors
Rule proposal phase (CR-102)
June 16, 2025
- Proposal Notice - CR-102 form
- Proposed rule language (173-424 WAC)
- Preliminary Regulatory Analysis
- SEPA Determination of Non-significance (DNS) and Environmental Checklist
Comment period
Comments are due by August 1, 2025, 11:59 PM.
Comment period: June 16, 2025 at 12am – August 1, 2025 at 11:59pm
Ecology will review and consider all the comments received before rule adoption later this year. See above for documents related to the Proposal Phase of the rulemaking.
We accept comments in the following ways:
- Submit comments online
- Mail to:
For standard US Mail-
Department of Ecology
Climate Pollution Reduction Program
Adam Saul
PO BOX 47600
Olympia, WA 98504-7600
For Parcel Service-
Department of Ecology
Climate Pollution Reduction Program
Adam Saul
300 Desmond Dr SE
Lacey, WA 98503 - Attend a public hearing - see below
The hearings will begin with a short presentation and question and answer session, followed by the opportunity to provide testimony.
Tuesday, July 22, 2025, 10AM PT: Zoom Link
Wednesday, July 23, 2025, 1PM PT: Zoom Link
Location: online (webinar)
Register for the webinar to get your meeting ID and passcode.
To hear the webinar better or to call in only, use your phone (instead of the computer) to call 253-215-8782.
Agenda: Presentation, followed by public hearing
Accessibility: To request ADA accommodation for the public hearing, email Ecology’s ADA coordinator by July 17, 2025, or call 360-407-6831, 711 (relay service), or 877-833-6341 (TTY).
Full list of changes
- Updated requirements regarding the production of low carbon intensity alternative jet fuel, in alignment with Engrossed Substitute Senate Bill 5447 (Chapter 232, Laws of 2023).
- New requirements for electrolysis energy used in the production of alternative jet fuel and alternative marine fuel.
- Third-party verification requirements to improve the accuracy of information used to generate credits and deficits in the program.
- Amended requirements for the use of indirect (“book-and-claim”) accounting of low carbon intensity biomethane or electricity, which allows fuel producers to claim renewable electricity delivered to the grid or biomethane injected into a common carrier pipeline under certain conditions. The amendments aim to encourage in-state and regional renewable energy production and maximize local environmental benefits.
- Updated requirements to avoided methane crediting, which grant fuel producers additional credits for capturing methane that would otherwise be released into the atmosphere. The amendments establish new avoided methane crediting periods for biomethane produced from dairy and swine manure and organic waste diverted from landfills.
- Amended requirements related to capacity credits for zero emission vehicle infrastructure, including expanding credit generation opportunities to sites shared by multiple fleets.
- Updated requirements to harmonize the rule with California and Oregon’s clean fuel programs.
- Amendments to improve clarity and readability, correct errors, streamline reporting and registration requirements, and make other improvements to program implementation.
Related links
Contact information
Adam Saul
Environmental Planner
adam.saul@ecy.wa.gov
360-742-7998
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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.