After several years of development, NJDEP finalized Amendments to the Remediation Standards Rule (N.J.A.C. 7:26D) on May 17, 2021. The rule amendments include new legally enforceable indoor air standards for the vapor intrusion pathway. The six-month phase-in period ends on Nov. 17, 2021.
Order of Magnitude Evaluation Guidance Version 2.0 (May 2021) Indoor Air
The only indoor air remediation standard impacted by an order of magnitude or more decrease of an indoor air screening level is that of 1,1-dichloroethene. The remediation of sites or areas of concern that are active cases on or after May 17, 2021, is required to use the 21 ug/m3 (residential) and 88 ug/m3 (nonresidential) indoor air remediation standards for 1,1-dichloroethene.
Vapor Intrusion Screening Levels and Indoor Air Remediation Standards Tables
NJDEP posted comparison tables between the 2013 screening levels and new 2021 remediation standards for indoor air, as well as updated screening levels for rapid action, soil gas and groundwater for both residential and non-residential land uses.
For the groundwater vapor intrusion screening levels, of note: 2 compounds have more stringent standards 1,1-Dichloroethene Is dropped by an order of magnitude; 2 are added 1,4 Dioxane and 1,2,4 Trimethylbenzene. Also of note: 12 compound SLs are relaxed and 14 are removed.
For soil gas screening levels there are a significant number of changes for residential and non-residential.
For residential soils: Carbon tetrachloride & 1,2-Dibromoethane (ethylene dibromide) screening levels are more stringent and 1,1-Dichloroethene by an order of magnitude. Screening levels for 12 compounds are relaxed and 14 removed.
For the indoor air pathway, for residential and non-residential land uses, there have been a significant number of changes. Many of the residential standards have closed the gap with the laboratory reporting levels. The standard for 1,1-Dichloroethene is more stringent by an order of magnitude. Standards for 12 compounds are more stringent,including 9 compounds for non-residential land use.
For the Rapid Action Levels, the changes reflect the changes made to the indoor air standards for both residential and non-residential land uses.
The Vapor Intrusion Technical Guidance (Version 5.0, May 2021)
NJDEP revised the Vapor Intrusion Technical Guidance in May 2021. Changes include updated indoor air remediation standards, and a clarification of reporting requirements for indoor air and ambient air data.
NJDEP Technical Guidance Updates (2021)
NJDEP posted revised Technical Guidance related to implementation of the Remediation Standards Rule Amendments of 2021. Significant for vapor intrusion projects, changes were made to the rounding of sample analytical data reported for different project applications.
These changes to the rule and the technical guidance have increased the focus on collecting sufficient and representative data for the vapor intrusion pathway to support the remediation professional in their decision making process.
To learn more about these changes, register for our upcoming free webinar, Understanding the NJ Vapor Intrusion Remediation Standards 2021: How Does This Affect Your Laboratory Data? , scheduled for October 26th.