23071_Vega Metals_DM_20230412

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DECISION MEMORANDUM
DATE: 4/12/2023
FROM: Claire Sorrell TO: Brownfields Assessment File

RE: Vega Metals 214 and 216 Hunt Street Durham, Durham County BF # 23071-19-032
Based on the following information, it has been determined that the above referenced site, whose intended use is for no uses other than office, retail, restaurant, high-density residential, associated parking, and subject to DEQ’s prior written approval, other commercial uses, can be made suitable for such uses.

Introduction: The Prospective Developer (PD) is Lambert Development Hunt Street II, LLC, with its principal office at 421 8th Avenue, #852, New York, New York 10116. Lambert Development Hunt Street II LLC is a limited liability, full service real estate development
company. Its managing member is Henry A. Lambert of the same address.
The Brownfields Property, located on 214 and 216 Hunt Street, Durham, Durham County, is comprised of two parcels totaling 0.607 acres with the following address and parcel identification numbers: 214 Hunt Street (Parcel ID: 104937) and 216 Hunt Street
(Parcel ID: 104934). The Brownfields Property is bordered by a public park to the north
and west; Rigsbee Avenue with commercial properties beyond, and Hunt Street to the south with a paved parking lot beyond. Redevelopment Plans:
The PD constructed a six-story building with first floor retail and commercial space with
residential condominium units above on the Brownfields Property in accordance with a DEQ-approved Environmental Management Plan (EMP) dated November 4, 2020. Construction was completed by the end of 2022. The PD pre-emptively installed a vapor intrusion (VI) mitigation system (VIMS) at the Brownfields Property. Pre-occupancy
testing of the VIMS was performed in March 2023, and the report was provided on April
11, 2023. Site History: Development on the Brownfields Property was first noted in the 1907 Sanborn map,
where 214 Hunt Street is seen to be in a residential area. Occupancy records indicate that
the addresses of the two previous onsite residences, which were on the eastern portion of the site, appear from 1920-1958. The eastern portion of the site was used for parking between 1955 and the time that construction of the current project began.
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In the western portion of the Brownfields Property, development was first noted on the
1937 Sanborn map, where an auto repair shop and wood working shop are present.
Occupancy records of the site from 1969-1990 indicate that an auto rental and taxi garage occupied these buildings. From 1997-2014, Vega Metals is listed as an occupant of the site. There are no listings for 216 Hunt Street, but records associated with 218 Hunt Street indicate that it has been occupied by a roofing company (1930), auto repair shop
(1935, 1949), car rental company (1963 and 1969), taxi company (1954, 1958,1975), and
Cricket Forge (2002-2014). The PD purchased the property on May 30, 2019. Environmental assessment activities were conducted at the Brownfields Property in 2018 (S&ME, Inc.), 2020 (WithersRavenel, Inc.), and 2022 (WithersRavenel, Inc.).
Assessment included sampling and analysis of on-site groundwater and soil.
Two gasoline underground storage tanks (USTs) (1 - 1,500-gallon and 1 – 7,620 gallon) registered under Broadway Taxi Company (214 Hunt Street) were installed in 1955 and removed in December 1988. There were no reported releases associated with the USTs
and no NC DEQ UST Section Incident Number was assigned for the USTs that were
removed. A former closed-in-place UST and associated dispenser in the eastern manufacturing area of the building noted as an onsite Recognized Environmental Condition (REC) in
2018were removed from the Brownfields Property as part of the redevelopment efforts in
2021. No on-site residual soil contamination was noted as a result of this UST removal. Groundwater wells do not remain on the Brownfields Property (Email correspondence from Jim Conner, Calhoun, Bhella & Sechrest, on November 17, 2022)

Starting in February 2021, the PD began construction activities for a single six-story building containing residential condominium units above first floor retail and commerce tenants, and an underground parking structure. In April 2021, the PD removed the existing building slab. Grading activities resulted in the removal of impacted soil from
the western portion of the Brownfields Property for offsite disposal and the placement of
non-impacted soil from the eastern portion of the Brownfields Property to bring the western portion to construction grade. As noted in the Environmental Management Plan Implementation Report (WithersRavenel, February 22, 2022) “Structurally sound soils were transported from the area between the F Line and K line to the area between the A
line and F line to bring the site up to construction grade.” (see below, in red, Figure 1)
Excess soil from this portion of the Brownfields Property was also shipped to landfills. No soil from offsite was imported to the Brownfields Property. Impacted soils were removed from the site between July 9, 2021, and October 28, 2021,
which contained arsenic and lead at levels which exceeded the industrial/commercial
PSRGs, benzo(g,h,i)perylene, benzo(a)pyrene and hexavalent chromium at levels which exceeded the Residential PSRGs, and selenium at a level that exceeded the protection of groundwater PSRG. The following shipments, were documented under manifest: Waste
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Management’s Great Oaks Landfill in Randleman, NC accepted 195.45 tons of arsenic and lead impacted soils and 56.88 tons of petroleum impacted concrete originating from
the in‐place UST; EVO Corporation, Inc., accepted 989.37 tons of petroleum impacted
soils; The Upper Piedmont Regional Landfill, in Rougemont, NC, accepted 2,786.98 tons of geotechnically unsuitable soils. Additionally, Fogelman Landfill, in Durham County, accepted a total of 14,274 tons of inert soil and construction debris.
Potential Receptors:
Potential receptors are construction workers, on-site workers, future residents, visitors, pets, recreators and trespassers. Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property:
groundwater and soil. 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).

Risk Calculations: Risk calculations were performed using the January 2023 DEQ Risk Calculator https://deq.nc.gov/permits-rules/risk-based-remediation/risk-evaluation-resources. For the purposes of looking at the site spatially, the site was assessed as a whole using
default assumptions.
The risk calculations indicated the following based on available data, including the following media: groundwater, soil and sub-slab soil vapor.
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Soil
Soil samples were collected from ground surface to a depth of twenty feet below ground surface (ft bgs). Arsenic, benzo(a)pyrene, and hexavalent chromium concentrations were detected above their respective Residential Preliminary Soil Remedial Goals (PSRGs) in soil samples that remain at the Brownfields Property. Based on the risk calculator output,
the acceptable residential carcinogenic risk (CR) range maximum of 1E-4 was not exceeded for any risk scenario. The threshold noncancer hazard index (HI) of 1.0 was exceeded for soil for the residential direct contact soil risk scenario with a HI of 1.1; the risk driver being arsenic with a hazard quotient of 9.4E-1. Risk was not exceeded for any
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other receptor via any other pathway based on risk calculator output.
The soil data that was used in the risk calculator and the Exhibit 2 reflects the soil
remaining on the Brownfields Property after the soil removal and redistribution activities discussed above and noted below in Figure 1 occurred. Confirmatory soil sampling conducted at the base of the excavation, which extended to bedrock, was conducted on April 13, 14, 16 and 27, 2021. These samples indicate removal of impacted soils
containing lead and benzo(g,h,i)perylene in excess of their respective Residential PSRGs.

Groundwater Groundwater was found at depths between 4.47 feet below top of well casing and 22.3 feet below top of casing when sampled at the Brownfields Property. Monitoring data was
collected in 2018 and 2020. The direction of groundwater flow is variable, with a
potentiometric groundwater surface that indicated westward flow recorded in the February 2020 sampling event, and a potentiometric groundwater surface that indicated southeastern flow recorded in the April 2018 sampling event.
Since the concentration of chromium in the sample collected from TW-2, on 4/17/2018
exceeds the NC 2L standard, appropriate institutional control measures are necessary. Based on the risk calculator output, the acceptable residential carcinogenic risk range is not exceeded for residential, non-residential worker, construction worker, nor
recreator/trespasser scenarios with respect to exposure to groundwater. Additionally, the
threshold noncancer hazard index of 1.0 is not exceeded for groundwater or the groundwater to indoor air vapor intrusion pathway for residential or non-residential worker exposure scenarios. Surface Water Surface water is not located on nor borders the Brownfields Property. Exterior Soil Gas
Exterior soil gas sampling was not conducted prior to the construction of the building at
this Brownfields Property. The PD opted for a pre-emptive VIMS.
Sub-Slab Vapor Pre-occupancy sub-slab vapor samples were collected at nine sample locations on March
23, 2023. Based on the risk calculator output, the acceptable residential carcinogenic risk
(CR) range maximum of 1E-4 and the threshold noncancer hazard index (HI) of 1.0 were not exceeded for any risk scenario. However, it should be noted that samples with the tetrachloroethylene concentrations of 700 µg/L and 900 µg/L were collected. These concentrations exceed the residential vapor intrusion screening level of 280 µg/L.
Tetrachloroethylene and chloroform drive the risk in sub-slab vapor.
Two additional sub-slab vapor samples will be collected on the westernmost portion of the building after the final slab-on-grade floor has been poured.
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Indoor Air Indoor air samples were not collected for the pre-occupancy sampling because
trichloroethylene (TCE) had not been detected at the site previously. Concentrations of
PCE and TCE were detected in sub-slab samples collected on March 23, 2023. We will be working with the PD to collect paired sub-slab and indoor air samples to evaluate whether these concentrations may be related to indoor-air interferences.
Land Use Restrictions:
LURs will include the standard land use restrictions including approved land uses, land use definitions, specific prohibitions, requirement for an EMP, groundwater, soil disturbance, known contaminants, access, notification, vapor intrusion, and land use restriction update LURs.

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 Branch
The Environmental Management Plan was approved on November 4, 2020. Redevelopment activities concluded in late 2021, and the approved Environmental Management Plan Implementation Report was submitted on February 22, 2022. Pre-occupancy sampling occurred on March 23, 2023 and sample results indicated
tetrachloroethylene concentrations of 700 µg/m3 and 900 µg/m3 and a TCE
concentrations as high as 2.6 µg/m3 in sub-slab samples. We will be discussing future pre- and post-occupancy sampling with the Prospective Developer to determine whether there are indoor air source interferences.

Figure 1. Map of soil that has been removed from the site, in red, as presented in
Environmental Management Plan Implementation Report (WithersRavenel, Inc.,
February 22, 2022).
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