Chapters 173-425, 173-430, and 173-400 WAC, Flame Cap Kilns and Air Curtain Incinerators
We propose to update three rules:
- Chapter 173-425 WAC, Outdoor burning
- Chapter 173-430 WAC, Agricultural burning
- Chapter 173-400-050 WAC, Emission standards for combustion and incineration units
With this rulemaking, we propose to:
- Add the definition of flame cap kilns.
- Include flame cap kilns as an allowed burning device. A flame cap kiln is an outdoor container used to burn natural vegetation from forestry or agricultural activities.
- Make sure flame cap kilns are only used for burning that is already legal in Washington.
- Update the definition of silvicultural burning to include combustion.
- Permit the use of air curtain incinerators. An air curtain incinerator is a portable container used to burn woody debris (slash) from forestry operations.
- Make the process for getting a permit to use an air curtain incinerator easier for both applicants and staff.
Rulemaking timeline
Announcement phase (CR-101)
Filing date:
Feb. 6, 2025
Announcement documents
Rule development phase
February 6, 2025 – November 12, 2025Public input & involvement
Public comment period (informal)
April 8, 2025 – August 1, 2025
This rulemaking will include an environmental justice assessment, as required by the Healthy Environment for All Act (the HEAL Act, RCW 70A.02.060). We want to engage with communities and Tribes to hear their input and related environmental justice concerns. To get updates about these meetings and this rulemaking, join our email list.
Meetings with stakeholders
| Date | Meeting information | Location |
|---|---|---|
| Tuesday April 8, 2025 9 a.m. – 10:30 a.m. |
Presentation
|
webinar recording |
| Thursday June 5, 2025 9:30 a.m. – 11 a.m. |
Presentation Draft rule language 173-425 Draft rule language 173-430 Draft rule language 173-400 |
webinar recording |
| Tuesday July 22, 2025 8:30 a.m. – 10 a.m. |
Presentation Draft rule language 173-425 (same as previous draft) Draft rule language 173-430 (same as previous draft) Draft rule language 173-400 |
webinar recording |
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.
Rule proposal phase (CR-102)
Nov. 13, 2025
- Proposal notice – CR-102 form
- Proposed rule language
- Preliminary Regulatory Analyses
- SEPA Determination of Nonsignificance (DNS) and Environmental Checklist
Comment period
Comments are accepted November 13, 2025, at 12 a.m. – January 20, 2026, 11:59 p.m. We accept comments in the following ways:
-
Attend a public hearing online (webinar): January 6, 2026, 10 a.m.
- Mail to: Caitlyn Roehmholdt
Department of Ecology
Air Quality Program
P.O. Box 47600
Olympia, WA 98504-7600
Public hearing
Date/Time: January 6, 2026, 10 a.m. online (webinar)
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, question-and-answer session, followed by public hearing
Accessibility: To ask for ADA accommodation, email caitlyn.roehmholdt@ecy.wa.gov, call 360‑407‑6831, or dial 711 (relay service).
Related links
Contact information
Caitlyn Roehmholdt
Rulemaking Lead
caitlyn.roehmholdt@ecy.wa.gov
360-742-7554
Stay informed
Join our email list
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.