NJDEP Posts Updated Guidance Regarding Capping of Volatile Contaminants for the Impact to Ground Water Pathway

On February 5, 2019, the New Jersey Department of Environmental Protection (NJDEP) posted an update to its guidance document entitled Capping of Volatile Contaminants for the Impact to Ground Water Pathway. The original guidance document, issued on August 30, 2018, provided a new remedial alternative/compliance option to address the Impact to Ground Water (IGW) pathway. The updated version of the guidance document clarifies the responsibilities of owners and investigators with respect to the capping, inspection, and maintenance of volatile chemicals.

Prior to 2014, capping was generally not an appropriate remedy to prevent soil contaminants from impacting the ground water at a site. In 2014, NJDEP issued guidance entitled Capping of Inorganic and Semi-volatile Contaminants for the Impact to Ground Water Pathway, which provided the new compliance option of capping inorganic and semi-volatile organic contaminants as a method to address the IGW pathway under certain circumstances. Pursuant to the 2014 guidance document, volatile organic compounds (VOCs) such as Tetrachloroethene (PCE), Trichloroethene (TCE), and benzene, did not qualify for this remedial alternative.

In August 2018, NJDEP issued new guidance entitled Capping of Volatile Contaminants for the Impact to Ground Water Pathway, providing for the first time the remedial option to cap VOCs to prevent contaminants from impacting the ground water. The February 2019 update to this guidance leaves much of the original language unchanged, except for the following additions and revisions to the text. First, the updated guidance stresses the importance of investigating all contaminant exposure pathways in all cases, with a particular emphasis on the vapor intrusion (VI) exposure pathway. Additionally, Section 5.0 of the guidance document and its corresponding Figure 1 have been re-written to clarify the procedures based on whether the groundwater is already contaminated. Finally, the updated guidance contains a FAQ section to address common concerns.

If your property is contaminated with VOCs, it is vital to understand all of the compliance options available to you, as well as the benefits and drawbacks of each option. Capping can be an excellent remedial alternative with benefits such as cost-savings, and efficiency. However, by definition, this is a restricted use remedial alternative, which requires a deed notice pursuant to N.J.A.C. 7:26 C. GHC can guide you through the remediation process, and help you to assess your best options.

Co-Authored by Carmella Gubbiotti