Township Council Meeting — Packet

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