For the first time in program history, NJDEP has issued guidance that would allow volatile organic compounds (VOCs - like those contaminants found frequently at gasoline service stations, dry cleaners and manufacturing facilities) to be capped in-place and remain at the site. Historically, these petroleum and chlorinated VOCs had to be remediated to meet very stringent Impact to Groundwater default values which typically drove the costs associated with a remediation. If you have a site with these types of contaminants in New Jersey, whether you are in the investigation or remediation phase of the project, you should immediately assess your current data set in light of the new guidance.
The guidance, titled Capping of Volatile Contaminants for the Impact to Ground Water Pathway, was issued August 30 and contains a process for allowing VOCs to remain in soil, provided that a low permeability cap either exists or will be installed over the soils. The capping will require long term inspection and maintenance. The guidance can be implemented at sites where groundwater contamination has already been documented, as well as those where groundwater is not impacted or has not yet been investigated. Importantly, the guidance provides a procedure which can help remediators avoid the need to conduct a groundwater investigation, potentially shortening the time required to bring a site to closure. This guidance will supplement NJDEP’s 2014 guidance on Capping of Inorganic and Semi-Volatile Contaminants for the Impact to Ground Water Pathway.