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NEW – DWM Vapor Intrusion Guidance
The Division of Waste Management (DWM) has developed guidance for environmental professionals and internal staff to assist in the investigation and evaluation of vapor intrusion at contaminated sites. This guidance is applicable anywhere a vapor intrusion investigation is warranted by a program in DWM, except for the Underground Storage Tanks (UST) Section. For vapor intrusion investigations at sites contaminated with petroleum constituents only, please consult with the DWM program overseeing the investigation. If petroleum constituents are comingled with volatile organic compounds at a site being managed by a DWM program, the DWM Vapor Intrusion Guidance document should be used.
The DWM Vapor Intrusion Guidance document was developed using established guidance from the US Environmental Protection Agency (USEPA), the Interstate Technology and Regulatory Council (ITRC) and other states, modified for the purposes of DWM. The guidance document presents basic vapor intrusion investigation, sampling, evaluation and mitigation approaches and is intended to complement the rules and policies of cleanup programs in DWM. Any user of the DWM Vapor Intrusion Guidance document should always work in coordination with the appropriate DWM program overseeing the investigation of the site.
There are two parts to the vapor intrusion guidance – the DWM Vapor Intrusion Guidance document and the DWM Vapor Intrusion Screening Levels. To allow for flexibility in updating information on a frequent basis as USEPA revises the Regional Screening Level Tables, the DWM Vapor Intrusion Screening Levels are separate from the main guidance document.
The most current version of the DWM Vapor Intrusion Guidance document and DWM Vapor Intrusion Screening Levels will be presented on the home page of the DWM website. It is highly recommended that interested parties refer to this DWM home page to ensure that they are using the most current information in the investigation and evaluation of a site.
The state of science with regards to vapor intrusion is continually evolving; therefore, DWM will make updates to the guidance document as needed in order to continue to protect human health from exposures caused by subsurface vapor intrusion. The guidance document was prepared by DWM in cooperation with the DWM Remediation Team, a technical group comprised of representatives from all sections of DWM. Additionally, the guidance document was reviewed by several outside contractors and vapor intrusion professionals. It is DWM's intent to place the guidance document in use and solicit any feedback for future revisions as it is being used. Please submit any feedback on the concepts, layout, and scientific principles (via email only – no phone messages please) to Delonda Alexander, DSCA Remediation Unit Supervisor at Delonda.Alexander@ncdenr.gov for future revisions. Please do not submit any comments or questions regarding how to implement the contents of the guidance document. Implementation issues should be discussed directly with the appropriate DWM program overseeing activities at the site.