NJDEP Proposing to Amend Vapor Intrusion Technical Guidance

NJDEP Proposing to Amend Vapor Intrusion Technical Guidance

The New Jersey Department of Environmental Protection (NJDEP) is proposing changes to its Vapor Intrusion Technical Guidance (VIT Guidance)…

The New Jersey Department of Environmental Protection (NJDEP) is proposing changes to its Vapor Intrusion Technical Guidance (VIT Guidance) that will significantly increase the frequency and number of soil-gas sub-slab (SSSG) samples that would be required to be collected as part of the vapor intrusion investigation component of remediation of contaminated property.  If this proposal is adopted, it would significantly impact entities that develop Brownfield properties for use as large warehouses.

NJDEP Vapor Intrusion Guidance

N.J.A.C. 7:26E-1.8 defines Vapor Intrusion (VI) as “the migration of volatile chemicals from the subsurface into overlying buildings through subsurface soils or preferential pathways (such as underground utilities).” As noted by the NJDEP, the presence of volatile compounds in soil or groundwater offers the potential for chemical vapors to migrate through subsurface soils and along preferential pathways, potentially impacting the indoor air (IA) quality of affected buildings.

The NJDEP’s VIT Guidance is designed to help individuals responsible for conducting remediation, such as licensed site remediation professionals, comply with the NJDEP’s requirements established by the Technical Requirements for Site Remediation.

Proposed Change to SSSG Sampling Requirements

The VIT Guidance was last amended in January 2018 (Version 4.1). The NJDEP is now proposing several new revisions.  One of the most significant changes involves the requirements for conducting vapor intrusion investigations, which will be amended to reflect the recent incorporation of vapor intrusion screening levels in the NJDEP’s official remediation standards. The proposed changes call for increased SSSG VI sampling frequency, particularly for larger buildings.

As the name implies, SSSG samples are collected from below the building foundation or slab. As highlighted by the NJDEP in the existing VIT Guidance, SSSG sampling can be useful for assessing the VI pathway from several perspectives, including:

• The primary utility for collecting SSSG samples is to assess if there is a potential for a complete VI pathway to exist. A VI pathway is considered complete only when the following occurs: a source of vapors, related to a discharge (e.g. soil and/or groundwater plume), is identified; and
• A pathway connects the source to potential human receptors inside a building.

The VIT Guidance sets forth the minimum number of SSSG samples that must be collected. It also lists certain building-specific features and conditions that necessitate additional samples, which include, but are not limited to the following:

• Presence of sensitive populations
• Past usage (e.g., dry cleaners, vapor degreasers, underground storage tanks)
• Building construction (separate foundations, type of slab, footers, utility lines etc.)
• Presence of earthen or damaged floors
• Presence of sump pits
• Requests from building owner
• Elevator pits
• Portion of building overlying or contacting the highest levels of VOC
• Areas of greatest exposure (playrooms, family rooms, classrooms, offices)
• Homogeneity and composition of sub-slab material

In addition, NJDEP is proposing to increase the SSSG VI sampling frequency requirements as follows:

Key Takeaways

The NJDEP is currently soliciting feedback regarding these proposed changes. Assuming they become final, entities that plan to redevelop brownfields and other properties requiring remediation will need to take the new requirements into account when determining the path forward and costs of such projects.

If you have questions, please contact us

If you have any questions or if you would like to discuss the matter further, please contact me, Dan McKillop, or the Scarinci Hollenbeck attorney with whom you work, at 201-896-4100.