NJDEP Updates Vapor Intrusion Screening Levels and Guidance - Time to Pause and Reassess Your Cleanup
In a long-awaited and key agency action, the New Jersey Department of Environmental Protection ("NJDEP") has updated its vapor intrusion screening levels ("VISLs") and the Vapor Intrusion Technical ("VIT") Guidance document for conducting vapor intrusion investigations at contaminated sites. The updated January 2013 VISL tables were developed using newly published risk-based information from the United States Environmental Protection Agency ("USEPA").
The VISL tables were revised to include changes to toxicity factors and risk-based equations used to calculate the VISLs to account for the new EPA information. This resulted in increases in VISLs for some compounds and decreases for others. For example, the VISLs for 1,1-Dichloroethane, Ethylbezene, and 1,2,4-Trichlorobenzene all decreased by an order of magnitude while VISLs increased for many chemicals, most notably the non-residential Indoor Air Screening Level ("IASL") for Tetrachloroethene ("PCE") increased from 3 ug/m3 to 47 ug/m3. In addition, two new chemicals were added to the VISL tables - 2-Methylnaphthalene and Naphthalene and five chemicals were deleted from the tables.
Groundwater screening levels were also revised which may have an impact on the need to conduct on-site and off-site vapor intrusion assessments. Finally, rapid action levels were revised, which will affect whether a particular vapor intrusion condition constitutes a high priority immediate environmental concern ("IEC") or a lesser priority vapor concern ("VC"). This characterization may affect compliance timeframes and reporting obligations for vapor intrusion conditions. A change in site status as IEC or VC must be confirmed and justified by the site's Licensed Site Remediation Professional ("LSRP") with the NJDEP vapor intrusion case manager.
All new cases initiated after January 16, 2013 must follow the applicable Technical Rules and regulatory/mandatory timeframes using the new VISLs. For existing cases initiated prior to January 16, 2013 the NJDEP has developed a VISL implementation strategy as follows:
- No further investigation for the vapor intrusion pathway is required for sites which were issued unrestricted use final remediation documents for groundwater prior to January 16, 2013.
- Sites issued restricted use final remediation documents for groundwater prior to January 16, 2013 will require an evaluation of the pathway as part of the biennial certification process.
- A review of existing data for order of magnitude changes will need to be performed to evaluate if additional remediation is required for Remedial Action Workplans issued prior to January 16, 2013.
- All other sites will have 90-days (April 16, 2013) to evaluate all existing site conditions and data using the new VISL.
The legal and technical implications of the new VISLs could be significant. We strongly recommend that any sites at which conditions requiring vapor intrusion mitigation have been previously identified be re-evaluated as soon as possible, together with sites at which it was previously concluded that no mitigation was required.