These amendments addressed cleanup standards for mixtures of dioxins and furans, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The revisions include:

• Risk Policies Applicable to Certain Mixtures
  
  
  • Cleanup levels for dioxin and furan mixtures must be based on a cancer risk of one-in-a-million;
  • Cleanup levels for PAH mixtures must be based on a cancer risk of one-in-a-million;
  • Cleanup levels for PCB mixtures must be based on a cancer risk of one-in-a-million.
    
    
• Toxic Equivalency Factors Used:  Incorporates the most recent toxicity equivalency factors (TEFs) for dioxins/furans and PCBs recommended by the World Health Organization and updated potency equivalency factors (PEFs) for carcinogenic PAHs adopted by the California Environmental Protection Agency.
  
  

• Gastrointestinal Absorption Fraction:  The default Gastrointestinal Absorption Fraction used to establish soil cleanup levels for dioxins and furans was changed from 100% to 60%.

• Cross-Media Impacts: Cleanup standards must consider the physical-chemical properties of individual carcinogenic PAH compounds and dioxin congeners when evaluating cross-media impacts.
  
  
• Documents related to 2007 rule adoption:
  
• MTCA Rule Amendment
• Complete Rule OR
•  Amendments Only
• CR-103
• Final Cost Benefit and Least Burdensome Analysis
• Small business economic impact statement
• Concise Explanatory Statement and Response to Comment
• Appendix A - Final Rule Language
• Appendix B - Public Comments
• Implementation Plan
• Rule Adoption Notice
• SEPA Determination of Non-Significance
• Background Document for the Proposed Amendments to MTCA
• Contact:  Pete Kmet 360-407-7199
  

These amendments were passed to implement recommendations by the MTCA Policy Advisory Committee.  This committee, created by legislation passed in the 1995 session, was directed to conduct a comprehensive review of Ecology’s cleanup program.  The committee made numerous recommendations that resulted in both statutory amendments and major revisions to the entire MTCA rule.  Major areas addressed in this rule-making included:

• Use of site-specific risk assessments in setting cleanup levels and selecting remedies.
• Changes to the remedy selection process.
• Procedures for assessing impacts to upland plants and animals (terrestrial ecological evaluation).
• Procedures for assessing impacts of soil contamination on groundwater.
• Procedures for determining site-specific cleanup levels for petroleum contaminated sites.
• Documents related to 2001 rule adoption:
• 2001 Concise Explanatory Statement
  • Appendix A: Document Highlighting Differences between the Proposed Rule Amendments and the Adopted Rule Amendments
  • Appendix B: Comments on the 1999 Proposal -- Available by contacting Carol Dorn at (360) 407-7224 or cesg461@wa.gov.ecology
  • Appendix C: Comments on the 2000 Proposal -- Available by contacting Carol Dorn at (360) 407-7224 or cesg461@wa.gov.ecology
  • Appendix D: Calculations for Method A Cleanup Levels
• Least Burdensome Alternative Analysis for the Amendments to the Model Toxics Control Act Cleanup Regulation Chapter 173-340 WAC
• MTCA PAC (Policy Advisory Committee) Final Report
• Notice of Availability of the Final MTCA Environmental Impact Statement
• Final Estimates of the Probable Cost and Benefits of the Rule Amendments
• MTCA PAC (Policy Advisory Committee) Information

These amendments were made in response to a bill passed in the 1994 legislative session addressing use of agreed orders and authorizing Ecology to adopt cleanup standards for industrial properties. Issues addressed in this rule-making included:

• Allowed uses of agreed orders.
• Industrial Property Cleanup Standards.
• Institutional controls/deed restrictions.
• 1996 Responsivness Summary

These amendments were made in response to a bill passed in the 1993 legislative session providing for private rights of action under MTCA. Issues addressed in this rule making included:

• Costs charged to sites by department staff.
• Private rights of action.
• The voluntary cleanup program.
• Pre-payment agreements.
• 1993 Responsivness Summary

This created Part 7 of the MTCA Rule.

• 1991 Responsivness Summary

This created Sections 100 through 600 of the MTCA rule.

• 1990 Responsivness Summary