25046_Harrelson Ford Decision Memo 20230706

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DECISION MEMORANDUM DATE: July 6, 2023
FROM: Bill Schmithorst TO: BF Assessment File
RE: Harrelson Ford 6500 South Boulevard Charlotte, Mecklenburg County BF # 25046-21-060
Based on the following information, it has been determined that the above referenced site, whose intended use is for no uses other than multi-family residential and parking, can be made suitable for such uses. Introduction:
The Prospective Developer is TAC Harrelson Ford, LLC a limited liability company headquartered at 2100 Powers Ferry Road SE, Suite 350, Atlanta, Georgia. The Brownfields Property consists of one parcel (12306401) totaling approximately 10.58 acres. The northern portion of the Brownfields Property is developed with an approximate 2,000-sq ft warehouse building that is currently unoccupied; an approximate
9,300-sq ft service garage; an approximate 20,000-sq ft vehicle service showroom and service garage that is currently unoccupied; and an approximate 14,000-sq ft service garage that is currently unoccupied.
Redevelopment Plans:
Planned redevelopment of the Brownfields Property includes demolishing the existing buildings and construction of a townhome community. Additional unplanned uses may include industrial and commercial uses, with DEQ’s prior written approval.
Site History:
The Brownfields Property was first developed with a residence in the 1950s. By the early 1970s the property was developed with an auto sales showroom and service garage, and a separate building housing a service garage; an additional warehouse building and service garage building were constructed in 1983 and 1996, respectively. Automotive sales and
repair operations continued on-site from construction until 2020.
In 1994, one 3,000-gallon underground storage tank (UST) was removed from the Brownfields Property and confirmatory soil samples were collected from the base of the UST excavation which identified total petroleum hydrocarbon (TPH) as oil and grease at
concentrations up to 630 milligrams per kilograms (mg/kg). A No Further Action (NFA)
letter was issued on August 6, 1996. Environmental Assessments
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In January 2022, Phase II Environmental Site Assessment (ESA) sampling was completed at the Brownfields Property. Results of the assessment activities identified soil impacts in the vicinity of out-of-use in-ground hydraulic lifts and trench drains
associated with an oil/water separator. In addition, soil gas impacts were identified in areas historically utilized for auto repair operations. In March 2022, additional soil gas assessment activities were completed to further evaluate the impacts previously identified at the Brownfields Property, in accordance
with a DEQ-approved Work Plan. Results of the assessment activities identified chlorinated volatile organic compounds (cVOCs) at concentrations above the applicable screening criteria in soil gas samples collected beneath the two of the existing buildings historically utilized for auto repair operations.
To further evaluate the impacts previously identified beneath the two auto repair buildings, additional assessment activities, including sub-slab soil gas sampling and groundwater sampling, were completed in May and June 2022, in accordance with a DEQ-approved Work Plan. Results of the assessment activities identified soil, groundwater, and soil gas impacts at concentrations above the applicable screening levels
beneath the buildings in connection with former auto repair operations and the trench drain system. In February and March 2023, soil removal activities were completed in two buildings historically utilized for auto repair operations. The purpose of the soil removal activities
was to remove soil impacted by trichloroethylene (TCE). Results of post-excavation confirmation soil samples did not identify soil impacts at concentrations above the DEQ Residential Preliminary Soil Remediation Goals (PSRGs) with the exception of chloromethane detected in one sample location.

Potential Receptors: Potential receptors are construction workers, on-site workers, future residents, visitors. A Brownfields Receptor Survey was completed on July 30, 2021. No water supply wells
were identified within 500 feet of the Brownfields Property; however, seven water supply
wells were identified within 1,500 feet. The Brownfields Property is served by municipal water. Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
groundwater, exterior soil gas, and sub-slab soil gas. DEQ relies on the following data to base its conclusions regarding the subject property and its suitability for its intended reuse. Please see the Brownfield Agreement’s Exhibit 2 for specific sample locations, dates, and contaminants of concern (COCs).

Groundwater
• Tetrachloroethlyene was detected above NC 2L Groundwater Quality Standards.
• The source of tetrachloroethylene is suspected to be onsite.
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Soil
• Metals including arsenic and hexavalent chromium were detected in shallow soil above NC Residential Preliminary Soil Remediation Goals.
• Total Petroleum Hydrocarbons – Diesel Range Organics were detected above the DEQ Division of Waste Management Underground Storage Tank Section Action
Level.
Exterior Soil Gas
• VOCs were detected in exterior soil gas at concentrations above NC Residential Vapor Intrusion Screening Levels. Contaminants detected included petroleum and
chlorinated compounds. Trichloroethylene was not detected above Residential VISLs. Sub-Slab Soil Gas
• VOCs were detected in sub-slab soil gas at concentrations above NC Residential Vapor Intrusion Screening Levels. Contaminants detected included petroleum and chlorinated compounds. Trichloroethylene was not detected above Residential VISLs.
• The highest concentrations of contaminants detected in soil gas were found
beneath the buildings where vehicle maintenance was previously performed.
• Trichloroethylene was detected up to 2,000 µg/m3. Soil contaminated with TCE was subsequently excavated from the areas where elevated TCE levels were
detected. Additional soil gas sampling will be conducted to confirm that TCE
concentrations have been reduced. Indoor Air Indoor air samples were not collected because the existing buildings are being
demolished.
Surface Water Surface water is not present at the Brownfields Property.
Risk Calculations:
Risk calculations were performed using the July 2022 DEQ Risk Calculator https://deq.nc.gov/permits-rules/risk-based-remediation/risk-evaluation-resources. The site was evaluated by calculating the site risk using the worst-case contaminant concentrations detected in the media sampled. The risk calculations indicated the
following based on available data, including the following media: groundwater, soil,
exterior soil gas, and sub-slab vapor samples.
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Risk for Individual Pathways Output Form 1A
Version Date: July 2022
Basis: May 2022 EPA RSL Table
Site ID: 25046-21-060
Exposure Unit ID: Soil, GW, Exterior and Sub-Slab Soil Gas Worst Case
Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded?
Soil 3.3E-07 2.8E+01 YES
Groundwater Use*2.1E-04 4.5E-01 YES
Soil 7.7E-08 4.7E+00 YES
Groundwater Use*2.3E-05 8.5E-02 NO
Construction Worker Soil 1.3E-08 3.0E+00 YES
Soil 8.5E-08 7.2E+00 YES
Surface Water*NC NC NC
Receptor Pathway Carcinogenic
Risk Hazard Index Risk exceeded?
Groundwater to Indoor Air 4.2E-07 4.6E-02 NO
Soil Gas to Indoor Air 2.3E-03 1.5E+01 YES
Indoor Air NC NC NC
Groundwater to Indoor Air 9.7E-08 1.1E-02 NO
Soil Gas to Indoor Air 6.1E-05 1.2E+00 YES
Indoor Air 0.0E+00 0.0E+00 NO
VAPOR INTRUSION CALCULATORS
Resident
Non-Residential Worker
DIRECT CONTACT SOIL AND WATER CALCULATORS
Resident
Non-Residential Worker
Recreator/Trespasser

Based on the results of the risk evaluation, the Residential Hazard Index risk threshold
was exceeded for groundwater use, soil, and soil gas. Receptor risks for soil were driven by elevated petroleum hydrocarbon concentrations. Soil gas risks were driven by elevated concentrations of volatile chlorinated compounds and petroleum hydrocarbon compounds.

According to environmental data provided by the PD’s engineering consultant, the suspected VOC soil gas source areas are found in shallow soil beneath the former vehicle maintenance areas. Prior to development of the property, the PD is planning to excavate contaminated soil from beneath the former vehicle maintenance areas to remove the
suspected source areas. Confirmation soil gas samples will be collected after completion
of source removal activities. The soil remediation work is required under the Brownfields Agreement. In addition, pre-occupancy sub-slab soil gas sampling will be required in all buildings constructed near the source areas, and within other areas of the property, as necessary.

Elevated concentrations of petroleum-related compounds detected in groundwater will require a land use restriction prohibiting the use of groundwater; however, municipal water is available at the Brownfields Property, further minimizing the potential risks.
An Environmental Management Plan (EMP), approved by DEQ, will be required before
the start of soil grading or excavation activities to prevent exposure to site workers and future residents from unacceptable levels of contaminants, and to manage the safe handling and disposal of potentially contaminated materials during construction. In addition, final grade soil sampling will be required prior to occupying the Brownfields
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Property. Vapor intrusion mitigation systems will be required at each individual townhome unit. Based on soil gas concentrations, select townhomes will require active mitigation due to proximity to the former chlorinated VOC source areas.
Land Use Restrictions: The standard land use restrictions including land use, Environmental Management Plan and reporting requirements, prohibition on groundwater use, soil restrictions, the need for vapor intrusion mitigation, access, notification, and prohibition on the use of known
contaminants, and the annual land use update obligation are required for this Brownfields Agreement. In addition, townhome minimum use standards and brownfields townhome use language will be included in the Brownfields Agreement. Based on the site-specific data provided to the Brownfield program, the site reuse is
suitable for the site as long as the agreed upon land use restrictions in the BFA are abided by. PROPERTY MANAGEMENT ISSUES
• Townhome use
• EMP
• Targeted soil gas assessment in the source area excavation areas
• Final grade soil sampling required
• Vapor mitigation required. TCE detected in soil vapor.