Ecology opens 45-day comment period on draft Vapor Intrusion Guidance

• What is the purpose of this draft Vapor Intrusion Guidance?
• What kinds of comments is Ecology looking for?
• Should reviewers focus on specific areas?
• What is the relationship between this draft guidance and the ongoing MTCA Cleanup Regulation Update?
• When is the comment period?
• What will Ecology do with the comments received?
• Where do I send comments?
• How would Ecology like comments to be organized?
• Who should I contact if I have questions?

All comments on the document provided to Ecology by November 30, 2009, will be considered when the guidance is finalized. (Please see "Where do I send comments” below for instructions.)

What is the purpose of this draft Vapor Intrusion Guidance?

This technical guidance is intended to help responsible parties, environmental professionals, and Ecology site managers assess vapor intrusion at cleanup sites in Washington. 

Vapor intrusion (VI) refers to the vapor phase migration of volatile organic and/or inorganic compounds into occupied buildings from underlying contaminated ground water or soil. These substances may contaminate indoor air and impact human health.  This technical guidance document provides techniques for evaluating whether vapor intrusion has the potential to contaminate indoor air. It also recommends ways to protect building occupants.

This draft guidance includes the following:

Chapter 1:       Introduction
Chapter 2:       How to do a preliminary assessment to determine which areas and buildings that vapor intrusion could potentially affect.
Chapter 3:       How to further assess those site areas and buildings identified by the preliminary assessment. 
Chapter 4:       Interacting with the affected public.
Chapter 5:       Vapor intrusion mitigation techniques.
Chapter 6:       Deriving protective subsurface concentrations and evaluating the need for institutional controls.
Chapter 7:       References
Appendix A:     Terminology.
Appendix B:     Shallow groundwater and soil gas screening levels that protect indoor air.
Appendix C:     Soil gas sampling.
Appendix D:     Using the Johnson and Ettinger Model during vapor intrusion assessments.
Appendix E:      Estimating the contribution of vapor intrusion to indoor air using soil gas and indoor air measurement data.

What kinds of comments is Ecology looking for?

Please comment on any aspect of the draft Vapor Intrusion Guidance.  We welcome your thoughts. It is particularly helpful to Ecology if comments clearly identify a topic, the chapter, section, and page.  This enables us to better understand the context of your comments.

Should reviewers focus on specific areas?

The draft guidance addresses a wide range of vapor intrusion issues.  With a number of these issues, Ecology recognizes that a national consensus has yet to emerge.  Ecology is particularly interested in feedback on:

The tiered approach. For example, is using soil gas or groundwater data to make screening decisions reasonably conservative? We have tried to be consistent with the general approaches used by other state and federal agencies. Do you believe this is a reasonable approach for implementing the current MTCA rule provisions? If not, what do you suggest?

• The list of VI contaminants of potential concern. The draft list of screening levels is designed to provide a reasonably conservative approach for identifying potential VI problems that would be implemented within a tiered decision-making framework. Should additional chemicals be included on the list? Do you believe the benefits of a longer chemical list outweigh the potential costs?  If not, what suggestions do you have for modifying the list?
  
  
• Use of the Johnson and Ettinger model. Do the draft recommendations seem reasonable? If not, what do you suggest?
  
  
• Consideration of background concentrations resulting from indoor and outdoor sources of volatile hazardous substances. Do the draft recommendations seem reasonable?  If not, what do you suggest?
  
  
• Our recommendations concerning petroleum hydrocarbons. Are the draft recommendations reasonable?  If not, what do you suggest?
  
  
• Level of detail and terminology. Ecology received a wide range of comments on earlier drafts related to the use of qualitative terms (like “slightly above”).  Some commenters also felt we should be more consistent, or exact, in how we characterized our recommendations (when, for example, should “expect” be used versus “recommend”). Does the current document provide a reasonable balance between general guidance and specific recommendations?
  
  

What is the relationship between this draft guidance and the ongoing MTCA Cleanup Regulation Update?

This draft guidance supports implementation of the Model Toxics Cleanup Act (MTCA) cleanup regulation. Ecology is currently in the process of reviewing and updating this regulation. As part of this process, Ecology is examining the investigation and cleanup requirements applicable to vapor intrusion to determine if changes should be made.

Your feedback on this guidance document will help Ecology determine what rule changes (if any) might be needed to effectively deal with vapor intrusion problems at cleanup sites.

Ecology plans to complete work on the vapor intrusion guidance document in early 2010. The rulemaking process is currently scheduled to be completed in 2011. If necessary, Ecology will update the vapor intrusion document to reflect regulatory changes following rule adoption.

When is the comment period?

The comment period runs from October 16, 2009, through November 30, 2009.

What will Ecology do with the comments received?

All comments received by 5 p.m. on November 30, 2009, will be considered when the final version of the guidance document is prepared. Although we are unable to respond to each comment individually, Ecology will issue a general responsiveness summary that describes the issues identified by reviewers and explains the changes we made to the draft document in response.

Where do I send comments?

Send comments to: martha.hankins@ecy.wa.gov.   Please include VI Guidance in the subject line.

How would Ecology like comments to be organized?

Date
Your name
Representing
Contact information (mailing address, e-mail, phone number)
Topic/Chapter/Section/Page you are commenting on
Comments and supporting information

Who should I contact if I have questions?

If you have questions about the draft document or the commenting process, please contact Ed Jones at ed.jones@ecy.wa.gov  or (425) 649-4449. If you have comments about the MTCA cleanup regulation update, please contact Martha Hankins at martha.hankins@ecy.wa.gov  or (360) 407-6864.