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Alliance Environmental Group EPA Questions and Responses - January 29, 2016 One Mifflin Place Suite 400 Cambridge, MA 02138 617.492.6500 Memorandum DATE: January 29, 2016 TO: Ms. Kimberly N. Tisa, PCB Coordinator USEPA FROM: Joel Walcott, PE Felix Perriello, CHMM, CPG, LSP, LEP CC: Andrew McBeth Green Leaf Construction Robert Mucciarone, COO/Treasurer F.W. Webb PROJECT: Former Universal Steel & Trading Company Site 297 Bridge Street Salem, Massachusetts Alliance Environmental Group, Inc. (AEG) is pleased to provide our responses to your comments/questions provided in an email dated January 22, 2016, which was sent in response to our original Request for Risk-Based Disposal Approval pursuant to 40 CFR 761.61. Comments and Responses EPA Comment #1: Given the PCB concentrations that are present at the site, the proposed remedial plan EPA must consider the plan under the risk-based disposal option at 40 CFR § 761.61(c). Generally, any such approval would be issued to the property owner. However, EPA understands that the City currently owns the property. Please clarify at what point, F.W. Webb will acquire the property. AEG Reply #1: F.W. Webb Company (F.W. Webb) intends to purchase the property. Please issue approval to the pending property owner, F.W. Webb. The acquisition terms are currently under negotiation. EPA Comment #2: Is this Site still being used as a temporary parking lot for the MBTA train station? AEG Reply #2: No, the Site is currently a surplus parking lot. Memorandum January 2016 Former Universal Steel & Trading Company Site Page 2 EPA Comment #3: Based on the information provided in the proposed remedial plan, it appears that F.W. Webb is proposing to leave PCBs at the Site regardless of concentration, unless the soils are required to be excavated for site development. If soils are excavated, soils with PCB concentrations <10 ppm may be placed back on the Site beneath the cap. Please confirm that EPA’s understanding is correct. If so, please clarify if the <10 ppm PCB soils would be placed outside the new building footprint only or if the soils would also be placed beneath the new building footprint. AEG Reply #3: EPA’s understanding is correct. F.W. Webb will manage all soils requiring removal as part of development, but does not plan to over-excavate soils based on the results of the previous remedial excavation conducted by Weston & Sampson. Soils exhibiting <10 ppm of PCBs are proposed for reuse on-site beneath the engineered cap. The cap will consist of the building floor slab as well as asphalt or concrete pavement outside of the building footprint. Restrictions regarding the reuse of soils beneath versus outside of the building footprint (but under an engineered cap) was not anticipated to be required. EPA Comment #4: On page 9 of the October 2015 plan, it is stated “Soil suitable for disposal off-site as non-TSCA waste = 10 to 50 mg/kg”. This implies that PCB- contaminated waste at the Site is not regulated under TSCA. However, waste at the Site likely meets the definition of a PCB remediation waste as defined at 40 CFR § 761.3 and thus is regulated under TSCA. EPA assumes that the intent actually was that PCB waste with these concentrations would be disposed of at a state-permitted landfill rather than a TSCA-permitted landfill. Please confirm. AEG Reply #4: EPA is correct; the designation was intended to imply that these soils would be disposed of at a state-permitted landfill facility. EPA Comment #5: Page 7. There is reference to a geotechnical evaluation to confirm the appropriate building foundation design measures. The schedule provided on page 10 of the remediation plan indicates that this work was to be completed in November 2015. Was this evaluation conducted and if so, what was the result(s) and does it affect the utilization of the stone pier system to support the building floor slab? AEG Reply #5: The geotechnical soil borings have not been advanced. Commencement of the drilling program is pending MassDEP written or presumptive approval of the RAM Plan, to be submitted prior to initiation of the work. EPA Comment #6: Given that the Site is currently covered by asphalt, it is likely that some asphalt would be removed during site development work. Please clarify how any removed asphalt would be managed. AEG Reply #6: Soils below the asphalt pavement were previously excavated to a minimum depth of 1.5 feet below grade; the asphalt was installed above clean fill material and is not expected to be impacted. The asphalt will be considered general solid waste/construction debris unless otherwise instructed. Memorandum January 2016 Former Universal Steel & Trading Company Site Page 3 EPA Comment #7: Both the Release Abatement Measure (“RAM”) Plan dated October 2015 and the Soil & Groundwater Management Plan and Health and Safety Plan (“SGMP”) dated October 2015 contain a Figure 2 that shows the remaining PCB concentrations remaining at the Site. a. Please confirm that the PCB concentrations indicated on this figure were based on the data collected by EPA during the Removal Action conducted between 2012 and 2013. If so, please be aware that the samples were collected on approximately 25-foot grid intervals. Thus, additional in-situ PCB samples may need to be collected to confirm PCB concentrations for off-site disposal unless it is assumed that all such wastes contain PCBs at greater than or equal to (“≥”) 50 ppm. AEG Reply #7a: Confirmed; the information is based on the January 2015 Weston & Sampson report entitled Phase III Remedial Action Plan (RAP) and Permanent Solution with Conditions Statement. b. Given the information provided, EPA is unable to determine what soil would require excavation for installation of utility corridors and where the proposed stone columns would be installed. Is a figure available that shows where these structures would be? AEG Reply #7b: AEG is currently preparing this Site Figure which will be submitted to EPA under separate cover. EPA Comment #8: Page 6 of the SGMP refers to disposal of PCB concentration less than 50 mg/kg as non-TSCA waste. Please see previous comment 4 regarding the term “non-TSCA” and amend as necessary for clarity and compliance with 40 CFR Part 761. AEG Reply #8: The designation was intended to imply that “non-TSCA” soils would be disposed of at a state-permitted landfill facility. However, as indicated in the EPA comment #4, waste at the Site likely meets the definition of a PCB remediation waste as defined at 40 CFR § 761.3 and thus is in fact regulated under TSCA. EPA Comment #9: Page 6 of the SGMP. 3rd paragraph. It is inferred that disposal of the excavated soils will be based on the PCB concentration in each stockpile. Please be aware that disposal requirements would be based on the as found (i.e., in situ) PCB concentrations, not the stockpile concentrations, unless higher PCB concentrations were identified in the stockpiles. Please also see previous Comment 7.a. regarding Site PCB concentrations. Please also be aware that for PCB-contaminated wastes, the stockpiling requirements at 40 CFR § 761.65(c) would apply. AEG Reply #9: Agreed; soil disposal requirements will be based on maximum detected PCB levels with a focus on the in situ concentrations. Stockpile samples may also be analyzed to provide additional data and/or as requested by the selected disposal facility. Memorandum January 2016 Former Universal Steel & Trading Company Site Page 4 EPA Comment #10: Page 6 and Page 9 of the SGMP. Given the high water table at this and as discussed on page 9, there is a possibility that groundwater could be encountered during soil excavation work. If so and if that soil will be disposed off-site, please include in the discussion how “saturated” soil would be stockpiled and managed, including free liquids, for off-site disposal. AEG Reply #10: If dewatering is required, groundwater will be pumped into frac tanks for off-site disposal. A significant amount of saturated soils is not expected to be encountered based on the limited excavation requirements below the water table. Dewatering will remove a majority of the free liquids prior to soil removal, and proper stockpiling methods will prevent the runoff of any additional residual liquids. EPA Comment #11: Page 7 of the SGMP. The 2nd paragraph references “sediment”. Please clarify what this refers to specifically at the Site. AEG Reply #11: This accounts for sediment that is expected to be generated and stored in 55-gallon steel drums following cleaning of the frac tank. The vehicles transporting these drums were included in this paragraph to confirm that they would also be inspected/cleaned as needed before leaving the site. EPA Comment #12: Pages 8 and 9 of SGMP. It is unclear why disposal of groundwater would only be regulated under the MCP. In addition, there is no discussion as to why the PCB regulations at 40 CFR § 761.79 would not apply to decontamination of the frac tank if it was used to hold/treat potentially PCB-contaminated groundwater. AEG Reply #12: The sentence on page 9 referring to MCP compliance will be amended to include acknowledgement of federal requirements for groundwater disposal. Please also note that the Decontamination Plan (Section 9.0) is intended to include the procedures, equipment, and personnel associated with the frac tank cleaning and residual waste disposal process. EPA Comment #13: Section 9.0 of SGMP. For the decontamination procedures, please be aware that the provisions of 40 CFR § 761.79(c) would pertain to decontamination of PCB-contaminated field equipment. As described, it is not clear if the procedure meets the self-implementing requirements under §761.79(c). Alternatively, samples could be collected to confirm that the appropriate decontamination standard has been achieved. Also, as indicated previously, any generated waste that contains PCBs above allowable standards would be regulated for disposal under 40 CFR Part 761. AEG Reply #13: F.W. Webb proposes self-implementing the decontamination procedures as outlined in 40 CFR §761.79(c), and acknowledges that any decontamination wastes generated will be required to meet the applicable standards. F.W. Webb will conduct the appropriate testing, rinsing, and other decontamination procedures pursuant to 40 CFR §761.79(c).