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Comment period

Flame Cap Kilns and Air Curtain Incinerators, Chapters 173-425, 173-430, and 173-400 WAC

Proposed rulemaking – public comment period

Nov. 13, 2025, 12 a.m. - Jan. 20, 2026, 11:59 p.m. PT

We are proposing to update three rules:

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.

Background

We write rules to implement and enforce state and federal environmental laws and rules.  Ecology follows a three-phase process for rulemaking:

  1. Announcement and development
  2. Proposal
  3. Adoption

For each phase of the process, we update the rulemaking web page and notify interested parties. We also file notice in the Washington State Register. To learn more about Ecology’s rulemaking process, read the Frequently Asked Questions.

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Comment online

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Comment by mail

Caitlyn Roehmholdt
Washington Department of Ecology
Air Quality Program
P.O. Box 47600
Olympia, WA 98504-7600
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Questions

Caitlyn Roehmholdt
Rulemaking Lead
caitlyn.roehmholdt@ecy.wa.gov
360-742-7554
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