Policies and guidance for site cleanups

If you’re cleaning up contaminated sites in Washington, you'll need to meet the requirements of the state’s cleanup law, the Model Toxics Control Act (MTCA) and the rules adopted under it: MTCA Cleanup Regulations and Sediment Management Standards.

We have policies and guidance that interpret the laws and rules. They'll help you meet MTCA's requirements so you can navigate your cleanup more easily.

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Cleaning up contaminated sites?

We’ve developed policies and guidance that interpret Washington’s cleanup law and help you clean up contaminated sites. These interpret the Model Toxics Control Act (MTCA) and its two adopted rules: the MTCA Cleanup Regulations, also known as the "Cleanup Rule" (for cleanups on land or groundwater) and the Sediment Management Standards, also known as the "SMS Rule" (for cleanups in freshwater or marine environments).

Policies interpret specific cleanup requirements. Some include templates pre-loaded with standard language. Policies help cleanup managers apply MTCA across many types of cleanups — as different as tanks leaking petroleum into the Columbia River, to dry-cleaners seeping toxic chemicals into the soil.
Procedures put policies into action. They often identify roles and responsibilities, such as who files an environmental covenant to make sure a remedy keeps working in the future.
Implementation memoranda and guidance answer frequently asked questions and offer best practices for successful cleanups.

Why do we need policies and guidance to interpret MTCA?

MTCA's requirements can be challenging to navigate — especially when cleanups are complex or involve contaminated sediment along a shoreline. Policies and guidance help you meet the requirements found in:

Model Toxics Control Act (MTCA) – Chapter 70A.305 RCW (MTCA law)
MTCA Cleanup Regulations (aka the MTCA Cleanup Rule) – Chapter 173-340 WAC (for all cleanups)
Sediment Management Standards (aka the SMS Rule) – Chapter 173-204-WAC (for sediment cleanups)

Procedure Number	Title	Revised
320	Site Hazard Assessment and Ranking of MTCA Sites by Ecology Staff	June 2004
321	Site Hazard Assessment of MTCA Sites by Local Health Districts/Departments	June 2004
440A	Establishing Environmental Covenants under the Model Toxics Control Act. We are currently revising this procedure (Feb. 2024).	Being revised
440C	Releasing Environmental Covenants under the Model Toxics Control Act Access Procedure 440C (PDF) Download Attachment B as a boilerplate you can edit in Microsoft Word: Termination and release of covenant: Template and instructions	December 2016
500A	Identification of Potentially Liable Persons (formerly Procedure 500B)	May 2016
550A	Cost Recovery under a MTCA Order or Decree	September 2018
550B	Property Liens under RCW 70.105D.055	July 2012

Policy Number	Title	Revised
120A	Independent Remedial Actions	December 2016
130A	Coordination of MTCA and SEPA	July 2004
300	Site Discovery	June 2004
310A	Initial Investigations	December 2009
310B	Creating or Changing the Name, Address, or Identification Number for a Facility or Site	October 2011
330A	Listing of Sites on the Hazardous Sites List	October 2004
330B	Removal of Sites from the Hazardous Sites List	October 2004
340B	Managing TCP's Program Plan	October 2008
500A	Identification of Potentially Liable Persons	May 2016
520A	Consent Decrees	April 2018
520B	Prospective Purchaser Agreements	August 1994
520C	De Minimis Consent Decrees	December 2016
530A	Agreed Orders	April 2018
540A	Enforcement Orders	April 2018
550A	Cost Recovery	February 2015
550C	Prepaid Cleanup Oversight	June 2006
560B	Granting Mixed Funding for LUST Cleanups	October 2017
600A	Site Register Publication	August 2008
710A	Permit Exemptions for Remedial Actions under MTCA (formerly Policy 130B)	November 2015
730	Taking into Account Federal Human Health Surface Water Quality Criteria under MTCA. [Rescinded. Details in Ecology Site Register announcement 1/26/2023]	Rescinded January 2023
800A	Property Access	February 1991
800B	Information Access	February 1991
840	Data Submittal Requirements	April 2016
900	Underground Storage Tank (UST) Enforcement	September 1992
920	Providing Public Participation in UST Settlements	October 2017
930	Investigation and Response to Complaints of UST Violations	October 2017
940	Voluntary Cleanup Program and Sediment Sites	February 2024

Number	Title	Revised
Memo #1	Guidance on the use of maximum contaminant levels as cleanup levels. [See MCL procedure in WAC 173-340-720(7)(b) and Developing Ground Water Cleanup Standards under MTCA]	Withdrawn February 2001
Memo #2	Applicability of WAC 173-340-706	August 1993
Memo #3	Practical Quantitation Limits as cleanup standards	Withdrawn August 2012
Memo #4	Determining compliance with Method A Cleanup Levels for diesel and heavy oil	June 2004
Memo #5	Collecting and preparing soil samples for VOC analysis	June 2004
Memo #6	Nematode bioassay protocol for soil toxicity screening	August 2004
Memo #7	Soil moisture corrected reporting by EPA Method 8000C	February 2008
Memo #8	Natural background for dioxins/furans in WA soils	August 2010
Memo #9	Building code compliance for factory built commercial structures	May 2011
Memo #10	Evaluating the human health toxicity of cPAHs using TEFs	April 2015
Memo #11	Dioxins, furans, and dioxin-like PCB congeners: Addressing non-detects and establishing PQLs for ecological risk assessments in upland soil	July 2015
Memo #12	When to use EPA Method 1668 for PCB congener analyses	July 2015
Memo #13	Dioxins, furans, and dioxin-like PCB congeners: Ecological risk calculation methodology for upland soil	July 2016
Memo #14	Updated process for initially assessing the potential for petroleum vapor intrusion [Obsolete. See Guidance for Evaluating Vapor Intrusion in Washington State: Investigation and Remedial Action]	Historical as of March 2022
Memo #15	Frequently asked questions (FAQs) regarding empirical demonstrations and related issues	June 2016
Memo #16	Developing conditional points of compliance at MTCA sites where groundwater discharges to surface water	July 2017
Memo #18	Petroleum vapor intrusion (VI): Updated Screening Levels, Cleanup Levels, and assessing PVI threats to future buildings [Obsolete. See Guidance for Evaluating Vapor Intrusion in Washington State: Investigation and Remedial Action]	Historical as of March 2022
Memo #19	Gasoline and diesel soil concentrations predicted to be protective of upland ecological receptors	August 2017
Memo #20	Frequently asked questions (FAQs) regarding model remedy implementation	March 2017
Memo #21	Frequently asked questions (FAQs) regarding vapor intrusion (VI) and Ecology's 2009 Draft VI Guidance [Obsolete. See Guidance for Evaluating Vapor Intrusion in Washington State: Investigation and Remedial Action]	Historical as of March 2022
Memo #22	Vapor intrusion (VI) investigations and short-term trichloroethene (TCE) toxicity [Obsolete. See Guidance for Evaluating Vapor Intrusion in Washington State: Investigation and Remedial Action]	Historical as of March 2022
Memo #23	Concentrations of gasoline and diesel range organics predicted to be protective of aquatic receptors in surface waters	August 2021
Memo #25	Identifying Likely Vulnerable Populations and Overburdened Communities under the Cleanup Regulations	January 2024

Major Cleanup Topics	Major Guidance Documents
Climate change	Sustainable Remediation: climate change resiliency and green remediation (guidance manual) Climate change and cleanup (two-page focus sheet)
Empirical demonstrations	Visit webpage at left for information
Model remedies	Model remedies for sites with petroleum impacts to groundwater Model remedies for sites with petroleum contaminated soils FAQs for implementing model remedies (Implementation Memo 20)
PFAS at cleanup sites (per- and polyfluoroalkyl substances)	Guidance (June 2023) Focus on: PFAS cleanup levels
Petroleum cleanups	CLARC: Cleanup Levels and Risk Calculation spreadsheet Guidance on remediation of petroleum-contaminated ground water by natural attenuation Guidance for remediation of petroleum contaminated sites (also called "TPH Guidance" and "Total Petroleum Hydrocarbons Guidance") Guidance for silca gel cleanup in Washington state
Remedial action plans & reports	Visit webpage at left
Sediment cleanups	Sediment cleanup user’s manual (SCUM) Wood waste cleanup: Identifying, assessing, and remediating wood waste in marine and freshwater environments
Terrestrial Ecological Evaluations (TEE)	DRAFT Terrestrial Ecological Evaluation guidance
Underground Storage Tanks/Leaking Underground Storage Tanks (UST/LUST)	Resources for underground storage tank owners and operators
Vapor intrusion	Guidance for evaluating vapor intrusion in Washington state: Investigation and remedial action (March 2022) Focus sheet on trichloroethylene (TCE) in residential indoor air

Who develops these documents?

Our Toxics Cleanup Program's Policy and Technical Support Unit develops policies and guidance in collaboration with cleanup project managers and technical staff statewide. These scientists, engineers, toxicologists, lawyers, hydrologists, and writers also provide technical assistance to people involved in a cleanup, such as cleanup project managers, property owners, environmental consultants, and local governments.

Legal disclaimer: These documents represent the Toxics Cleanup Program’s interpretation of the Model Toxics Control Act. These documents are not intended, and cannot be relied on, to create rights, substantive or procedural, enforceable by any party in litigation with the State of Washington. Ecology may act at variance with them depending on site-specific circumstances, or modify or withdraw them at any time. Changes to the statute or regulations may affect the statements contained in these documents.

Contact information

Policy and Technical Support Unit
360-407-7170