NJDEP to Allow Capping as Remedial Option for VOCs with Groundwater Pathways
At the end of August, the New Jersey Department of Environmental Protection (“NJDEP”) issued guidance that allows volatile organic compounds (“VOCs”) released to groundwater to be left in place under certain circumstances; the change could provide considerable cost savings for parties responsible for such releases. NJDEP’s new guidance will permit capping to be considered as a remedial option for sites with VOC risks or impacts to groundwater. See Capping of Volatile Contaminants for the Impact to Ground Water Pathway. The new policy supplements guidance issued in 2014, which allowed for capping of inorganic and semi-volatile organic contaminants under certain circumstances, but had not included VOCs, such as certain gasoline constituents, acetone, benzene, toluene, TCE, PCE, xylenes, and others. See Capping of Inorganic and Semi-Volatile Contaminants for the Impact to Ground Water Pathway. VOCs are often found in subsurface contamination at gasoline service stations, dry cleaners, and manufacturing facilities.
The new guidance sets certain requirements and restrictions for capping. For example, free and residual product must be removed to the extent practicable; low permeability caps must be used, such as concrete or clay, to prevent infiltration from precipitation and runoff; and the site must undergo a specified period of vapor monitoring to ensure that the cap is sufficiently protective of groundwater. Sites that are approved for capping will have a restricted use, requiring a deed notice under N.J.A.C. 7:26C. Sites will also be required to obtain a Remedial Action Permit for long-term maintenance of the cap until the Impact to Ground Water Soil Screening Levels and/or site-specific Impact to Ground Water Soil Remediation Standards are met.
NJDEP’s new policy has the potential to reduce costs for remediation of sites with VOC contamination, and sites currently undergoing remediation for VOCs should be reassessed to consider whether capping is an appropriate remedy. Parties responsible for remediating sites with VOCs should check with legal counsel or a licensed site remediation professional to determine whether and how NJDEP’s new guidance may apply to their sites.