Township Council Meeting — Packet

. The organic clayey silt stratum is underlain by a layer of fine sand. 2.4 Regional Hydrogeology The Site is located within the Piedmont Province, which consists of primarily of lowland and gently rolling hills above which rise the Watchung Mountains. The Brunswick Formation is the predominant formation in the region. The formation consists of inter-bedded brown, reddishbrown, sandstone. Three sets of gray to black basalt are intermixed with sandstone of the Brunswick Formation. Glacial deposits, consisting predominantly of till, overlay the rocks. P:\I00 CME7\West Orange\DPW 25 Lakeside Ave\VI Investigation 2023\VI letter Report\VI Letter Report - DPW West Orange - April 2023.docx

Bureau of Case Assignment &Initial Notice Re: Vapor Intrusion Investigation Report West Orange DPW 25 Lakeside Ave April 2023 Page 7 The bedrock of the Brunswick Formation is generally capable of sustaining moderate yields to wells. The Watchung basalt is capable of yielding only small quantities of water. Water occurs both under unconfined and confined conditions in these bedrock formations. The aquifers are anisotropic and water moves along the joints and fractures. 2.5 Site Hydrogeology A review of the results of the previous investigations indicates monitoring wells have been set in the overburden water bearing unit. Groundwater within this unit was encountered during the last sampling event at depths ranging from approximately 4.0 to 9.0 feet bsg and it appears to be under unconfined conditions. Lateral groundwater flow within the overburden aquifer was determined to be generally South-Southeast. 3.0 VAPOR INTRUSION INVESTIGATION CME’s personnel visited the Site on March 30, 2023, to investigate the building and to complete an indoor air quality survey within the building. The Site is currently improved with a single-story cinder block building (circa 1980) on a concrete slab foundation, includes an office area and a DPW maintenance area and storage garage. 1. Office Area: Offices, Dormitory/Waiting Room, Kitchen and Storage Room 2. DPW Garage - Maintenance area and storage garage Repair area with overhead-bay doors Exterior areas consist of asphalt driveways and parking lots on the southwestern and eastern side of the structure. The Site is bound to the north by the Former Barton Press Site (also former Edison complex), followed by Columbia Street and residential dwellings. The Site is bound to the west by the Former Barton Press Site (also former Edison Complex) followed by Main Street. The Site is bound to the south by Twin Towing followed by Lakeside Avenue and commercial properties including AWISCO (a welding supply company), and Joachim Driving School. The Site is bound to the east by Watchung Avenue followed by residential dwellings. During the period of March 31 and April 2, 2023, CME conducted a VI investigation at the Site. The VI investigation was performed to evaluate the potential impacts to indoor air quality as a result of volatile organic vapors emanating from groundwater plume around the building at the Site. P:\I00 CME7\West

tigation was performed to evaluate the potential impacts to indoor air quality as a result of volatile organic vapors emanating from groundwater plume around the building at the Site. P:\I00 CME7\West Orange\DPW 25 Lakeside Ave\VI Investigation 2023\VI letter Report\VI Letter Report - DPW West Orange - April 2023.docx

Bureau of Case Assignment &Initial Notice Re: Vapor Intrusion Investigation Report West Orange DPW 25 Lakeside Ave April 2023 Page 8 The vapor intrusion evaluation included the collection of a total of ten (10) air samples comprising three (3) indoor air samples (IA-1 through IA-3), six (6) sub-slab soil gas samples (SSGS-1 through SSSG-6) and one (1) ambient air sample (AA-1) from outside the building. Prior to sampling, CME representative, with the help of the property owner’s representative, completed the Indoor Air Quality–Building Survey Form to account for potential additional sources of VOCs (not related to the discharge at the Site) that may affect the air sample collected from the building. The indoor air samples were collected first inside the building to avoid the potential for crosscontamination between the soil gas and indoor air. Appendix 1 presents the Indoor Air Building Survey and Sampling Form. Figure 2 presents the Vapor Intrusion Investigation Sampling Location Plan. Summary of Sampling Results Indoor Air Sampling Results – Office Area: Concentrations of benzene were reported above the VI Exposure Pathway Remediation Standard Criteria in samples IA-1, IA-2 and IA-3 at concentrations that exceeded the Non-Residential and Residential Indoor Air Remediation Standards, however they were below the Rapid Action Levels (RAL). Benzene was not detected in any of the sub-slab soil gas samples collected within the office floors area, which indicates that detected benzene is not related to vapor intrusion issue at these locations. It could be related to using an air freshener or cleaning detergent at these locations, no further action is necessary for this pathway. Ethylbenzene was detected below the Non-Residential VI Indoor Air Remediation Standards in samples IA-1, IA-2 and IA-3 at concentrations that exceeded only Residential Indoor Air Remediation Standards (does not apply to the Site), however they were below the Rapid Action Levels (RAL). In addition, ethylbenzene was not detected in any of the sub-slab soil gas samples collected within the office floors area or garage floor area, which indicates that detected ethylbenzene is not related to vapor intrusion issue as there is no completed VI exposure pathway at these locations. It could be related to using an air freshener or cleaning detergent at these locations, no further action

ated to vapor intrusion issue as there is no completed VI exposure pathway at these locations. It could be related to using an air freshener or cleaning detergent at these locations, no further action is necessary for this pathway. P:\I00 CME7\West Orange\DPW 25 Lakeside Ave\VI Investigation 2023\VI letter Report\VI Letter Report - DPW West Orange - April 2023.docx

Bureau of Case Assignment &Initial Notice Re: Vapor Intrusion Investigation Report West Orange DPW 25 Lakeside Ave April 2023 Page 9 Based on the assessment of the results, these contaminants are found in the IA, but not the SSSG samples. These compounds are likely originating from background sources unrelated to VI and there is no completed VI exposure pathway. In this case, the Mitigation Decision Matrix directs the investigator to evaluate vadose zone (soil) contamination and preferential pathways as potential contributors to IA contamination, it is established that VI is not contributing to the IA contamination, no further action is necessary for this pathway. Concentrations of trichloroethene were reported above the Residential VI Exposure Pathway Remediation Standard Criteria in samples IA-1, IA-2 and IA-3 at concentrations that exceeded only Residential Indoor Air Remediation Standards (does not apply to the Site), however they were below the Rapid Action Levels (RAL). Trichloroethene was detected above the Non-Residential and Residential Soil-Gas Screening Levels in the sub-slab soil gas samples. Therefore, long -term monitoring (LTM), without system installation, may be the appropriate mitigative action. Table 1 presents the analytical results of the indoor air gas samples. Indoor Air at DPW Garage - Maintenance Area – Storage/Repair Garage : Indoor Air sampling was not conducted within the DPW Garage. In general, the investigator should not collect IA samples in a building (or portion of a building) where operations use, handle or store the same investigative Contaminant of Concern (COC) (e.g., dry cleaners, active gas service stations, maintenance facilities, various industrial operations). In these situations, it is difficult to determine whether air contaminants present in a building are from operational activities within the facility or from the subsurface (VI). “As recommended by the NJDEP Vapor Intrusion Technical Guidance, indoor air samples were not collected at (fill in name/address of specific building) due to operational use, handling or storage of the investigative COC within the building (insert alternative language if appropriate based on site-specific circumstances). Thus, the VI pathway at this building is “indeterminate.” Unless otherwise dictated by permit requirements, annual inspections of this building are necessary to

based on site-specific circumstances). Thus, the VI pathway at this building is “indeterminate.” Unless otherwise dictated by permit requirements, annual inspections of this building are necessary to identify any change in use. A change in use necessitates the prompt completion of the VI investigation consistent with N.J.A.C. 7:26E-1.15.” Sub-slab Soil Gas Sampling Results: Benzene was detected in one sub-slab soil gas sample (SSSG-4) located within the DPW garage area at a concentration 2.5 µg/m3 which is below the Non-Residential and Residential Soil-Gas Screening Levels. P:\I00 CME7\West Orange\DPW 25 Lakeside Ave\VI Investigation 2023\VI letter Report\VI Letter Report - DPW West Orange - April 2023.docx

Bureau of Case Assignment &Initial Notice Re: Vapor Intrusion Investigation Report West Orange DPW 25 Lakeside Ave April 2023 Page 10 Concentrations of trichloroethene were reported above the Non-Residential and Residential SoilGas Screening Levels (SGSL) in samples SSAS-2, SSSG-3, SSSG-5 and SSSG-6. Based on the assessment of the results, trichloroethene is found in the sub-slab soil gas (SSSG) samples but below the Non-Residential Indoor Air Remediation Standards in the indoor air (IA) samples. In this case, the Mitigation Decision Matrix indicates that sampling results of SSSG that are greater than the SGSL but at or less than 10 times the Non-Residential SGSL, long-term monitoring (LTM) is recommended. The following details the recommended LTM schedule: First year LTM: 1. Annual inspection of building 2. Sampling of IA during heating season. After first year LTM: 1. Annual inspections of building 2. Sampling of IA every five years Table 2 presents the analytical results of the sub-slab gas samples. Appendix 2 presents the Indoor Air, Ambient Air and Sub Slab Gas Laboratory Analytical Results, QA/QC Documents and Chain of Custody Forms. P:\I00 CME7\West Orange\DPW 25 Lakeside Ave\VI Investigation 2023\VI letter Report\VI Letter Report - DPW West Orange - April 2023.docx

Bureau of Case Assignment &Initial Notice Re: Vapor Intrusion Investigation Report West Orange DPW 25 Lakeside Ave April 2023 Page 11 (Excerpts from NJDEP Vapor Intrusion Guidance, dated May 2021- Version 5.0 ) 4.0 CONCLUSION The analytical results of the vapor intrusion investigation indicated that all volatile organic compounds were below the most stringent NJDEP regulatory levels. The results of the soil gas and indoor air investigations and the “building walkthrough and survey” were evaluated in accordance with the criteria outlined in the Decision Flow Chart for Vapor Intrusion Pathway and Section 3.1 of the VIG Document. Based on the investigation results reviewed by CME and according to the NJDEP Vapor Intrusion Guidance, no further vapor intrusion investigation action is required at the Site. Future monitoring/ long-term monitoring (LTM) is recommended as detailed above. P:\I00 CME7\West Orange\DPW 25 Lakeside Ave\VI Investigation 2023\VI letter Report\VI Letter Report - DPW West Orange - April 2023.docx

Bureau of Case Assignment &Initial Notice Re: Vapor Intrusion Investigation Report West Orange DPW 25 Lakeside Ave April 2023 Page 12 NJDEP Variance: Since the last update of the Technical Rules (August 6, 2018) and available variances (February 4, 2019), the Department has implemented changes related to the VI pathway that will be reflected in the future regulatory revisions. The following available VI related variances are recognized by the Department and acceptable for use by the investigator: • 7:26E-1.7(a) – The Department no longer requires notice on a separate form prior to varying from a technical requirement. The Variance Identification form is no longer available. Rather, on each Key Document form (i.e., SI, RI, RA, etc.), complete the section indicating that the particular phase of the remediation includes a variance taken under N.J.A.C. 7:26E-1.7. • 7:26E-1.15(c)1 – The Department no longer expects a notification (by form or spreadsheet) of future sampling events. • 7:26E-1.15(g) – The Department no longer utilizes the Heath Department Notification Levels. In addition, the Department no longer requires the submission of indoor and ambient air analytical results to the New Jersey Department of Health, except for samples collected at educational facilities and child care centers as defined in "Standards for Indoor Environment Certification and for Licensure of Indoor Environmental Consultants," N.J.A.C. 8:50-1.3 and pursuant to N.J.A.C. 7:26E1.15(h). "Per the Department's direction as noted in the NJDEP Listserv entitled "[SRRA]: Submission of indoor and ambient air analytical results to the New Jersey Department of Health," indoor and ambient air analytical results, including all maps and figures related to the indoor air sampling, and a sample location spreadsheet do not need to be submitted to the New Jersey Department of Health pursuant to N.J.A.C. 7:26E-1.15(h) unless samples are collected at educational facilities or child care centers as defined in "Standards for Indoor Environment Certification and for Licensure of Indoor Environmental Consultants", N.J.A.C. 8:50-1.3." P:\I00 CME7\West Orange\DPW 25 Lakeside Ave\VI Investigation 2023\VI letter Report\VI Letter Report - DPW West Orange - April 2023.docx