23064_Dick Keffer Pontiac_Decision Memo

DECISION MEMORANDUM DATE: September 8, 2021
FROM: Peter Doorn TO: BF Assessment File
RE: Dick Keffer Pontiac Buick GMC 1001 Tyvola Road and 450 Minuet Lane Charlotte, Mecklenburg County Brownfields Project No. 23064-19-060
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, office, parking, retail, and with prior written DEQ approval other commercial uses, can be made suitable for such uses.
Introduction: The Brownfields Property comprises approximately 10.524 acres and consists of two parcels located at 1001 Tyvola Road and 450 Minuet Lane which are identified as Mecklenburg County parcel numbers 16908402 and 16908410, respectively. The Brownfields Property is in a primarily commercial and industrial area of lower South End
Charlotte and located near the Lynx Blue Line light rail. The Brownfields Property and adjacent property to the east and south are zoned for Transit Oriented Development, while the surrounding properties north and west are zoned for industrial use.
The Brownfields Property was developed with a 53,946-square foot (sq. ft.) automotive
dealership building and a 1,468 sq. ft. office building. The northwestern portion of the property contains undeveloped wooded land and an unnamed tributary to Kings Branch. The remainder of the Site consists of asphalt-paved parking, access drives, and landscaped areas. The property has been vacant since 2018 and the dealership buildings
were demolished in late 2020.
Redevelopment Plans: The original Prospective Developer (PD), Tyvola Station Partners, LLC applied to the Brownfields Program in November 2019, and received their Letter of Eligibility for the
project on February 10, 2020. The initial Brownfields Property Application included
three parcels totaling approximately 12.1 acres, however, in February 2021, the eastern most parcel (1035 Tyvola Road – Parcel #16908401) was removed from the Brownfields Property with DEQ’s approval. On April 19, 2021, Tapestry Tyvola, LLC acquired the Brownfields Property and on May 18, 2021, submitted a revised application seeking
Brownfields eligibility, which was granted on July 20, 2021. The PD has committed to
redevelopment for high-density residential, office, parking, retail, and with prior written DEQ approval, other commercial uses. Redevelopment plans include construction of
four multi-family apartment buildings and associated amenities, two public streets, and surface parking.
Site History: From at least 1938 until 1976, the Brownfields Property was primarily agricultural or undeveloped wooded land with two residential structures along the eastern property boundary. The main automotive dealership building was constructed in 1976 and
operated as Dick Keffer Pontiac GMC. In 1987, a small office building was constructed for truck sales and was later used as a collision center office. A paint/autobody building was added onto the northern end of the dealership building in 2005. The property has been vacant since 2018. The northwestern portion of the Brownfields Property contains undeveloped wooded land and an unnamed tributary to Kings Branch.

The property has been occupied by various automotive dealerships and been used for
service, repair, and paint/body shop operations from 1976 through 2018. Approximately
23 subgrade hydraulic lifts were located throughout the service garage, and in July 2019 the inground lifts and components were removed. Three approximately 1,000-gallon waste oil above ground storage tanks are in covered containment along the northern
portion of the dealership building. An oil/water separator (OWS) located in the southwest portion of the property collected fluids from floor drains located in the service garage and wash bay in the main dealership building prior to discharge to the municipal
sewer system. The installation dates of the lifts and OWS are unknown; however, it is likely they were installed when the dealership building was constructed. The subject property was identified as a Resource Conservation and Recovery Act (RCRA)-Small Quantity Generator (SQG) of ignitable (D001) and spent non-halogenated
solvent (F003 and F005) hazardous wastes. Two Notices of Violation were found in the Hazardous Waste Section files. In June 1996, RCRA violations were observed that included lack of a contingency plan, open drums, improperly labeled waste drums, and spilled waste observed on the sides of drums. A reinspection in July 1996 noted that the facility had returned to compliance. In May 1997, the facility was cited for lack of
inspections records, and had returned to compliance by June 1997. In October 1992, three underground storage tanks (USTs) installed in 1976 were removed from the property. The removal included a 3,000-gallon gasoline UST and dispenser system, and two waste oil USTs (550-gallon and 280-gallon). The release was assigned
UST Incident #27949. A Limited Site Assessment (LSA) in 2007 and follow-up sampling in 2008 indicated groundwater impacts above the NCAC 2L Groundwater Quality Standards but below the UST Section’s Gross Contaminant Levels. In March 2008, NCDEQ issued a risk based No Further Action letter which included the filing of a Notice of Residual Petroleum (NRP) prohibiting the use of groundwater on the property.
The NRP was filed in Mecklenburg County’s Register of Deeds office in March 2008. In addition to the LSA and follow-up sampling associated with the former USTs, the Brownfields Property was the subject of a Phase I Environmental Site Assessment dated
April 26, 2019, a Phase II Environmental Site Assessment dated July 29, 2019, and a
Brownfields Assessment Report dated May 15, 2020. The referenced reports include assessment data and maps for the 1035 Tyvola Road property, but because that parcel was removed from the Brownfields Property in February 2021, the discussion below only considers data for the current project configuration consisting of 1001 Tyvola Road and
450 Minuet Lane.
Potential Receptors: Potential receptors include residents, on-site workers, construction workers, and visitors.

Contaminated Media: DEQ has evaluated data collected from the following media at the subject property: soil, groundwater, soil gas/sub-slab vapor, sediment, and surface water. DEQ relies on the following data to base its conclusions regarding the subject property and its suitability for
its intended reuse.

Soil Soil sampling events occurred on the Brownfields Property in October 1992, October 2007, January 2008, June 2019, and March 2020.
Upon removal of the USTs in 1992, Spatco Environmental collected soil samples from the base of the gasoline UST excavation and dispenser system for analysis of total petroleum hydrocarbons (TPH) gasoline-range organics (GRO), and from the base of the waste oil USTs for analysis of Oil & Grease. The TPH GRO results were below the
laboratory reporting limit; however, Oil & Grease ranged from 560 mg/kg to 800 mg/kg exceeding the action level at the time of 250 mg/kg. During the LSA activities in October 2007, S&ME collected soil samples below each of the former waste-oil USTs. The results indicated total chromium at up to 77.3 mg/kg
exceeding the Soil-to-Groundwater Maximum Contaminant Concentration at the time of 27 mg/kg and the Residential Maximum Contaminant Concentration at the time of 47 mg/kg. In January 2008, S&ME collected additional soil samples to further assess chromium concentrations near the waste oil tanks and to evaluate background concentrations. Chromium concentrations near the waste oil USTs ranged from less than
the method detection limit to 1.9 mg/kg. On-site background chromium concentrations in soil were found to range from less than 0.65 mg/kg to 116 mg/kg. In March 2008, NCDEQ concurred that chromium was likely naturally occurring. The chromium analyses in 2007 and 2008 were not speciated, however, these chromium concentrations are generally consistent with the trivalent chromium concentrations from subsequent soil
assessments described below. During the self-directed Phase II ESA activities in June 2019, soil samples were collected to assess impacts associated with the oil/water separators, air compressor area, shop floor
drains, aboveground storage tank (AST) area, subgrade hydraulic lifts, and background
conditions. Soil samples from the hydraulic lifts were analyzed for TPH-DRO, and results indicated that 9 of the 23 lifts had concentrations exceeding the NC DEQ UST action level of 100 mg/kg. All VOCs and SVOCs were below the NC DEQ Preliminary Soil Remediation Goals (June 2021) with one exception. Sample SB-5 collected from one
of the shop floor drains detected the VOCs isopropylbenzene at 0.16 J mg/kg and p-
isopropyltoluene at 0.22 J mg/kg, neither of which has an established PSRG. The SVOC 1-methynaphthalene was also detected in SB-5 at 0.26 J mg/kg which exceeds the Protection of Groundwater PSRG. Arsenic and hexavalent chromium were the only metals detected above the PSRGs. Arsenic concentrations on the property exceeded the
Residential PSRG of 0.68 mg/kg and the Industrial PSRG of 3 mg/kg. Arsenic in
background samples ranged from 2.45 mg/kg to 3.12 mg/kg, while concentrations in targeted samples ranged from 0.589 J mg/kg to 2.89 mg/kg. Hexavalent chromium exceeded the Residential PSRG of 0.31 mg/kg in all soil samples analyzed for metals. Hexavalent chromium in background samples ranged from 0.569 J mg/kg to 0.797 J
mg/kg, while concentrations in targeted samples ranged from <0.318 mg/kg to 0.374 J
mg/kg. Trivalent chromium concentrations in soil ranged from 5.86 mg/kg in L-17 to 83.304 mg/kg in SB-11, generally consistent with the total chromium concentrations reported from the 2007 and 2008 analyses.
In March 2020, additional assessment under a Brownfields-approved workplan included sampling soil in the undeveloped wooded area in the northwest portion of the property,
and sampling soil from the five lifts with the highest TPH-DRO levels for VOCs, SVOCs, RCRA metals, and PCBs. All PCB results were below the laboratory reporting limits. All VOCs and SVOCs detected were below the Residential and Industrial PSRGs. However, tetrachloroethylene was detected in one lift sample at 0.0165 mg/kg, exceeding the Protection of Groundwater PSRG of 0.0063 mg/kg. The only metals exceeding
Residential PSRGs were arsenic and hexavalent chromium, but concentrations of both are within the range of background concentrations documented on the property. Groundwater Groundwater sampling occurred on the Brownfields Property in October 2007, January
2008, June 2019, and March 2020. In October 2007, S&ME installed two monitoring wells near the waste oil tanks as part of the LSA activities. Results from the October 2007 sampling event indicated 2L Standards exceedances for benzene, 1,2-dichloroethane, bromodichloromethane,
dibromochloromethane, and chromium. Follow-up sampling in January 2008 confirmed the 2L Standards exceedances for benzene and 1,2-dichloroethane. During the Phase II ESA activities in June 2019, seven temporary wells were installed upgradient and at locations near the oil/water separator and downgradient of the service
garage. In March 2020, an additional temporary well was installed in the northwest undeveloped portion of the property. The VOC 1,2-dichloroethane was detected in TW-4 at 1.8 ug/L and TW-6 at 4.3 ug/L and was the only parameter detected above its 2L Standard of 0.4 ug/L.

Detected constituents in groundwater with the potential for vapor intrusion include benzene, 1,2-dichloroethane, and bromodichloromethane. Benzene in MW-1 and MW-2 exceeded the Residential GW VISL of 1.6 ug/L; 1,2-dichloroethane in MW-1, MW-2, and TW-6 exceeded the Residential GW VISL of 2.2 ug/L; and bromodichloromethane in
MW-1 exceeded the Residential GW VISL of 0.88 ug/L.

Surface Water In March 2020, surface water sampling was performed on the Brownfields Property to assess water quality in the urban unnamed tributary in the northwest portion of the
property that flows to Kings Branch. Surface water was sampled at the upgradient and
downgradient property boundaries. No VOCs or SVOCs were detected. Metals concentrations detected were compared to the more conservative of the freshwater aquatic life standard for Class C waters or the source of drinking water standard for Class WS-I waters. Cadmium was detected in the upstream sample at 0.347 J ug/L, exceeding
the chronic freshwater aquatic life standard of 0.15 ug/L. Lead was detected in the
upstream (1.39 ug/L) and downstream (0.734 ug/L) samples in excess of the chronic freshwater aquatic life standard of 0.54 ug/L. Mercury and silver were not detected, but
the laboratory reporting limit for both metals exceeded the chronic freshwater aquatic life standards of 0.012 ug/L and 0.06 ug/L, respectively.
Sediment In March 2020, sediment sampling was performed on the Brownfields Property to assess sediment quality in the urban unnamed tributary that flows to Kings Branch. Sediment samples were collocated with surface water sampling points at the upgradient and downgradient property boundaries. No SVOCs were detected in the sediment. Acetone
was the only VOC detected in sediment, with concentrations ranging from 0.0282 J mg/kg to 0.144 mg/kg, well below the Residential PSRG of 12,000 mg/kg. The metals arsenic and hexavalent chromium were detected in sediment above the Residential PSRGs but within the range of background soil concentrations specific for the Brownfields Property.

Soil Vapor and Sub-Slab Vapor In June 2019 four temporary soil vapor sampling points (SG-1 through SG-4) were installed in the proposed footprints of the four apartment buildings, and five temporary sub-slab vapor sampling points (SSV-1 through SSV-5) were installed below the floor of
the existing buildings. In March 2020 five additional soil vapor points (SG-5 through SG-9), and three additional sub-sab vapor points (SSV-6 through SSV-8) were installed to supplement the vapor intrusion assessment. Soil gas borings were installed to depths of 6 to 8 ft bgs and sub-slab vapor samples were collected immediately below the slab. Several VOCs were detected at each point and the notable detections that exceeded the
June 2021 Residential Soil Gas (SG) VISLs (based on a cancer risk of 1.0E-6 and an HQ of 0.2) were benzene, 1,3-butadiene, ethylbenzene, and naphthalene. Since more than five compounds were detected in each soil vapor sample, the DEQ Risk Calculator was used to further evaluate the potential risk from vapor intrusion. Because the property is
bisected by the unnamed tributary to Kings Branch, maximum soil gas concentrations
from the northwestern part of the property were evaluated separately from those in the southeastern part of the property. For the northwestern part of the property, the worst-case scenario resulted in a residential carcinogenic risk of 1.3x10-5 and a residential non-carcinogenic Hazard Index (HI) of 0.51. For the southeastern part of the property the
worst-case scenario resulted in a residential carcinogenic risk of 4.0x10-5 and a residential
non-carcinogenic HI of 1.2. However, the vapor intrusion cancer risks and the HIs associated with each apartment building footprint were within acceptable ranges with cancer risks ranging between 3.4x10-6 to 2.7x10-5, and non-cancer HIs ranging from 0.51 to 0.79.

Methane During the soil vapor and sub-slab vapor sampling in March 2020, soil vapor points SG-5 through SG-9 and Methane-1, and sub-slab vapor points SSV-5 through SSV-7 were screened for methane. No methane was detected at any of the sampling points.

Indoor Air Indoor air at the Brownfields Property was not collected because all buildings will be demolished prior to construction of the apartment buildings.
Risk Calculations
The DEQ Risk Calculator was developed to evaluate the risk of multiple contaminants and multiple exposure routes associated with contaminated environmental media at a site. The risk evaluation procedures, equations, and default parameters used to create the calculator follow the current USEPA risk assessment guidance. The DEQ Risk Calculator dated January 2021 was used to calculate risk based on data available for
media including soil and sediment, groundwater, surface water, and soil/sub-slab vapor. These calculations were performed prior to release of the June 2021 Risk Calculator, but since no chemicals of concern were updated in the recent release, the calculations of January 2021 Risk Calculator were retained.
The southeastern part of the Brownfields Property where the historic dealership operations occurred is separated from the undeveloped northwestern portion of the property by an unnamed tributary to Kings Branch. Maximum concentrations from each media from the southeastern and northwestern portions of the property were used to calculate risks. Risk Calculation Table 1 displays the risk calculated for the southeastern
portion of the Brownfields Property. Table 1a lists the soil gas to indoor air risks for each proposed building footprint. Risk Calculation Table 2 displays the risk calculated for the northwestern portion of the property. Risk Calculation Table 3 displays the risk calculated for exposure to the maximum sediment and surface water concentrations in the unnamed tributary to Kings Branch.

Table 1a - Soil Gas to Indoor Air by Building Footprint
Location Resident – Carcinogenic Risk Resident – Hazard Index Building #1 2.0x10-5 0.79
Building #2 3.4x10-6 0.51
Building #3 2.7x10-5 0.53
Building #4 1.3x10-5 0.51

Based on the detections of metals and organic compounds (primarily DRO) in soil,
restrictions regarding soil will be imposed at the site. Areas of known DRO impacts
exceeding UST actions levels around the lifts are to be included on the plat map. A UST
Notice of Residual Petroleum (NRP) restricting groundwater use was recorded on the property in 2008, and subsequent Brownfields assessment activities have confirmed exceedances of the 2L Standards. A groundwater use restriction will be included in the
BFA, and the UST Section was notified on March 18, 2021, that a BFA is being developed for the property and will include LURs superseding the NRP. Using maximum soil gas concentrations from across the site, indoor air risks are calculated to have an HI of 1.2, however, using maximum concentrations from within the footprint of each proposed building the indoor air risk HIs ranged from 0.51 to 0.79 (Table 1a).
Furthermore, no TCE was detected in any media at the Brownfields Property. While a vapor intrusion control system was recommended, the PD elected to begin construction without a vapor mitigation system, and consequently, a minimum of three semi-annual sub-slab sampling events will be required for each apartment building.
The Environmental Management Plan (EMP) approved by DEQ on June 10, 2020, will need to be followed to safely direct the handling and disposal of potentially contaminated materials when AST removal, building demolition, soil grading, or excavation activities begin. Prior to occupying the Brownfields Property, per the terms of the EMP, final grade soil sampling will be required for areas not covered by a minimum of 2 feet of
demonstratable clean fill, landscaping soil, or asphalt, concrete, or other impervious surface. Required Land Use Restrictions:
• No use other than multi-family residential and associated parking, drives, and walkways without DEQ approval.
• Approved EMP to be followed
• Annual development summary report required
• Demolition must comply with state & local requirements
• ASTs must be removed with 90 days of recordation
• No use of groundwater or surface water
• No soil import/export without DEQ approval
• Final grade sampling required where needed
• No soil disturbance without DEQ approval or EMP
• Vapor intrusion monitoring required
• DEQ shall not be denied access
• Any required wells or vapor points must be maintained
• Deed or other instrument conveying an interest shall contain the Notice
• No use of contaminants known to be present on the BF Property
• Annual LURU to DEQ
Based on the site-specific data provided to the Brownfield program, the site is suitable for the approved uses only if the agreed upon land use restrictions in the BFA are abided by.