Updating the Cleanup Rule

The Cleanup Rule (Chapter 173-340 WAC) sets standards and procedures for cleaning up contaminated sites under Washington's environmental cleanup law, the Model Toxics Control Act (MTCA). We are updating this rule in several stages, called rulemakings. Each rulemaking will focus on selected topics. This approach will help speed adoption of the changes that are most urgent for people who use the rule.

We completed the first rulemaking, which focused on procedures for conducting cleanups. The amended rule was adopted in August 2023, and went into effect on Jan. 1, 2024.

We used an exploratory rulemaking process to identify priorities for updating the Cleanup Rule.


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Changes in the first rulemaking

We completed the first rulemaking in 2023. This rulemaking focused on improving the process of prioritizing, investigating, and cleaning up contaminated sites. We will update technical cleanup standards in a future rulemaking.

The amended rule:

  • Includes provisions to help reduce environmental health disparities, so all residents can enjoy a clean, healthy Washington. Low-income populations and people of color historically are more affected by toxic releases than others. The new rule requires Ecology to consider these populations when prioritizing sites for cleanup and selecting cleanup actions. 
  • Assures Tribes that Ecology will consider tribal rights and interests during the cleanup process. For Ecology-conducted or supervised cleanups, Ecology will separately engage and collaborate with Tribes throughout the cleanup process.  
  • Improves the site hazard assessment and ranking process. The new ranking process will give us more information we can use to prioritize cleanups and allocate resources. We will also use the rankings to inform the public about the threats posed by contaminated sites.
  • Clarifies the cleanup process to help people meet cleanup standards. In particular, it lays out steps and requirements for studying the site and choosing which cleanup methods to use.
  • Improves initial response to regulated underground storage tank leaks and spills. The changes will help speed up investigations and cleanups to eliminate or reduce threats to our communities.

To learn more about this rulemaking, see the WAC 173-340 rulemaking webpage.

Your input shaped the Cleanup Rule update

We used an exploratory rulemaking process to shape our work on the MTCA rule. We held a statewide listening session in 2018. Participants suggested topics we should consider as we update the Cleanup Rule. We held the event both online and in Ecology’s offices throughout the state. You can download the webinar slides and read the suggested rule changes we received through this process.

Rule changes suggested by the public during the Cleanup Rule Exploratory Rulemaking between February 14 and May 11, 2018. Download a text description of this chart.

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