An Introduction to Vapor Intrusion Investigations in New Jersey

 For the New Jersey Department of Environmental Protection (NJDEP), 2012 has been a banner year. Here at REPSG, we have really had to stay on our toes to ensure that allNew Jerseysites are adhering to current regulatory guidance, form submittal requirements, and rules.

In January 2012, the new Vapor Intrusion Technical Guidance was finalized, providing lots of new details for the investigation of vapor intrusion into indoor air. Additionally, the Technical Requirements for Site Remediation (7:26E) was finalized in May 2012, providing the last word in receptor evaluation of populations being potentially impacted by harmful vapors. Now that all of the changes have been finalized, Suzanne Shourds and I plan to tackle the topic of vapor intrusion in an upcoming series of blog articles. We will be discussing the ins and outs of vapor intrusion as well as our own experiences with sites in New Jersey that have addressed potential vapor intrusion. These posts will cover vapor intrusion screening levels, receptor evaluations, the stages of a vapor intrusion investigation (groundwater, soil gas, and indoor air), mitigation, and the special requirements associated with Immediate Environmental Concerns and Vapor Concerns.ew Jersey Department of Environmental Protection (NJDEP), 2012 has been a banner year. Here at REPSG, we have really had to stay on our toes to ensure that all New Jersey sites are adhering to current regulatory guidance, form submittal requirements, and rules.

To get things started, let’s take a look at Vapor Intrusion Investigation Triggers, Screening Levels, and Receptor Evaluation (Stage 1).

When conducting a Site Investigation, the first step to take to address potential vapor intrusion is to identify a source, as well as a potential pathway (typically impacted groundwater) and possible receptors. Identification of all these components triggers the need for a Vapor Intrusion Investigation (Stage 2), addressed in the next blog post on this topic).

Once impacted groundwater with concentrations above the NJDEP’s Groundwater Vapor Intrusion Screening Levels is identified and delineated, all buildings (homes, apartments, commercial spaces, warehouses) and structures (garages, utility vaults, sheds) within 30 feet of petroleum-based impacts (including free product) and/or within 100 feet of non-petroleum-based groundwater impacts (including free product) must be considered potential receptors of vapor intrusion impacts and incorporated into the investigation.       A receptor must be present in order for there to be a potential vapor intrusion concern. This includes consideration of future receptors. Once the trigger is identified, the property owner has 150 days to conduct sampling of the identified receptors. Prior to conducting this sampling, all receptors must be characterized to identify building or structure use, size, and details (such as the presence of a basement).

Additional site triggers for a vapor investigation include: soil gas or indoor air data above Vapor Intrusion Screening Levels, a wet basement or sump containing free product or groundwater impacted with volatile compounds, methane-generating conditions, any other situation threatening health and safety that is related to vapor/indoor air.

Have a question about vapor intrusion investigation triggers? Leave a comment below or please feel free to contact me at jcutright@repsg.com. Please check back soon for our follow up article on Stage 2: Vapor Intrusion Investigation.