Chapters 173-424 WAC and 173-455 WAC

Ecology is starting rulemaking for a new rule, Chapter 173-424 WAC, Clean Fuels Program Rule and proposes to update Chapter 173-455 WAC, Air Quality Fee Rule.

This new rule may:

  • Establish carbon intensity standards for transportation fuels used in Washington.
  • Assign compliance obligations to fuels with carbon intensities that exceed the standard.
  • Establish compliance methods including assigning credits to fuels that have carbon intensities below the standard.

This rulemaking may also update Chapter 173-455 WAC to establish the process for setting fees to recover the cost of developing and implementing the program.

In May 2021, the governor signed the Transportation Fuels – Clean Fuels Program directing Ecology to adopt rules to reduce the carbon intensity of transportation fuels by 20 percent below 2017 levels by 2038. The law intends to reduce emissions of greenhouse gases and conventional air pollutants, and support the use of innovative clean fuel technologies.

Rulemaking timeline


Announcement phase (CR-101)

Filing date:
July 20, 2021

Announcement documents

Rule development phase

July 20, 2021 – Summer 2022

Public input & involvement

Public comment period (informal) – EXTENDED
October 6, 2021 – April 25, 2022 (originally April 10, 2022)

Comment online and read others' comments.

Ecology's meetings with stakeholders

Date Documents Location
October 6, 2021
9:30 a.m. – 12:30 p.m.
Meeting summary
webinar 1

November 16, 2021
2 p.m. – 5 p.m.

Draft rule language
Meeting summary
webinar 1
January 27, 2022
1:30 p.m. – 4:30 p.m.
Draft rule language
webinar 1
March 15, 2022
9 a.m. – noon
Draft rule language
WA-GREET draft model *
WA-GREET supplemental document
WA Crude Carbon Intensity Analysis
WA Crude Carbon Intensity Lookup Table
Indirect Land Use Conversion (ILUC)
webinar 1
April 13, 2022
9 a.m. – 12:30 p.m.
Draft rule language
WA Carbon Intensity Model Peer Review Report
WA Utility Carbon Intensity Calculator
WA-GREET supplemental document
WA Crude Carbon Intensity Analysis (updated)
Indirect Land Use Conversion (ILUC) (updated)
Tier 1 Carbon Intensity Calculator:
  • Biomethane from Landfills
  • Biomethane from Dairy, Swine Manure
  • Biomethane from Organic Waste
  • Biomethane from Wastewater Sludge
  • Renewable Diesel
  • Starch and Fiber Ethanol
  • Sugarcane-Derived Ethanol
  • Liquid Natural Gas and Liquid to Compressed Natural Gas
webinar 1

1 Webinar information:
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Additional languages

Español (Spanish) 中文 (Chinese) Tiếng Việt (Vietnamese) 한국어 (Korean)


To request ADA accommodation for disabilities, or printed materials in a format for the visually impaired, contact Ecology's ADA Coordinator by email at, 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.