Chapter 173-340 WAC

Ecology proposes to amend Chapter 173-340 WAC, the Model Toxics Control Act (MTCA) Cleanup Regulations.  As part of the rulemaking, Ecology is not proposing to change the cleanup standards in Parts 7 and 9 of the chapter, but is proposing to:

  • Update the title of the chapter.
  • Update the general provisions and defined terms in Parts 1 and 2 of the chapter.
  • Update the requirements for release reporting, initial investigation, site hazard assessment and ranking, site listing, and program planning under Part 3 of the chapter.
  • Update the requirements for conducting a remedial investigation and selecting a cleanup action for a site in Part 3 of the chapter.
  • Update the requirements in WAC 173-340-450 for investigating and cleaning up underground storage tanks regulated under Chapter 173-360A WAC.
  • Update the requirements for public participation and tribal engagement in Part 6 of the chapter.
  • Incorporate requirements for cultural resource protection in new WAC 173-340-815 and update procedures for identifying appropriate sampling and analytical methods in WAC 173-340-830.
  • Make other conforming and selective changes to the administrative and procedural requirements in Parts 4, 5, and 8 of the chapter.
  • Make other changes in Parts 1 through 6 and Part 8 of the chapter to streamline and clarify requirements, make minor corrections, and improve consistency with other laws and rules.
  • Make changes in Parts 7 and 9 of the chapter to clarify language and make corrections without changing the effect of the rule.
  • Incorporate changes to the cleanup program specified in Chapter 70A.305 RCW, the Model Toxics Control Act.

As part of the rulemaking, Ecology is proposing to replace the current site hazard assessment and ranking process specified in the rule (WARM) with an improved process developed outside the rule (SHARP).  The new SHARP is available separately for public review and comment through April 16, 2023.

This rulemaking is the first of several rulemakings that Ecology plans to undertake to update the MTCA Cleanup Regulations.  For more information about our plans, visit our Cleanup Rule Exploratory Rulemaking.

Rulemaking timeline


Announcement phase (CR-101)

Filing date:
Dec. 20, 2018

Announcement documents

Rule development phase

Dec. 20, 2018–Feb. 15, 2023

Public input & involvement

Rule proposal phase (CR-102)

Filing date:
Feb. 15, 2023

Rule proposal documents:

Additional documents:
The following additional documents are available to help in your review of the rule proposal:

Comment period

Comments due April 16, 2023

Ecology will review all comments received.  Ecology plans to adopt rule amendments in August 2023.  See above for documents related to the rule proposal.  

You can submit comments through one of the following ways:

  • Submit comments online.

  • Mail comments to:
    Sarah Wollwage
    Department of Ecology
    PO Box 47600
    Olympia, WA 98504-7600

  • Attend a Public Hearing – see below

Public hearings:

We are holding two public hearings on this rule proposal via webinar.  Webinars are an online meeting you can attend from any computer, tablet, or smartphone using internet access. The hearings will begin with a short presentation and question and answer session, followed by the opportunity to provide testimony.

Please note: Ecology will accept comments through the webinar. Comments will not be accepted through the chat box by persons viewing the webinar.

  • March 23, 2023 – 10:00 a.m.
    Webinar only via Zoom
    Join March 23 webinar online
    Join by phone (audio only): Call toll free 253-215-8782 and enter Meeting ID: 856 6571 0963
  • March 27, 2023 – 5:00 p.m.
    Webinar only via Zoom
    Join March 27 webinar online
    Join by phone (audio only): Call toll free 253-215-8782 and enter Meeting ID: 871 1342 5365

Any information (e.g., personal or contact) you provide may be publicly disclosed and posted on the Internet.

To request ADA accommodations, contact Ecology’s ADA Coordinator by March 16, 2023, at:

Additional languages

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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.