25008_North Hills Expansion_DM_20230901

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DECISION MEMORANDUM
DATE: September 1, 2023
FROM: Claire Sorrell TO: BF Assessment File

RE: North Hills Expansion 0 and 4140 Lassiter Mill Road Raleigh, Wake County Brownfields Project No. 25008-21-092

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, recreational, institutional, mixed-use development, 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 North Hills Retail Expansion Owner LP, with its principal office located at 4321 Lassiter at North Hills, Suite 250, Raleigh, NC 27609.
The Brownfields Property is comprised of two parcels near the intersection of Six Forks
Road and I-440, Raleigh with Wake County Parcel Identification Numbers (PINs): 1705593784 and 1705591660. At the time of the original application to the Brownfields Program on January 29, 2021, the Brownfields Property was comprised of three parcels with PINs 1705592477, 1705593807, 1705594776, and a fourth parcel, PIN 1705597841
for which a portion was included in the Brownfields Property. However, as noted in an
amended Brownfields Property Application (BPA) received on February 7, 2023, the original parcel references have been recombined to the two referenced above. A summary of the parcel history is provided below.
Table 1. Parcel History
Date Event June 28, 2022 PIN 1705597841 was combined with PIN 17805594776 and PIN 17805594776 was retired. PIN 1705597841 was subdivided into four parcels, three of which are located on the Brownfields Property (PINs 1705591518, 1705594779, 1706504120).
June 29, 2022 Parcel 1706504120 was subdivided, resulting in four parcels: 1705591518, 1705598812, 1705594779, 1706504120. Parcel 1705597841 was subdivided, resulting in 4 parcels: 1705598812, 1705591518, 1705594779, 1705594120.
June 30, 2022 PINs 1705593807, 1705592477, 1705591518, 1705594779, 1706504120 were recombined. Parcels 1705591660 (1.02 acres) and
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Date Event
1705593784 (6.16 acres), were split out. 1705591660 and
1705593784 have the addresses of 0 and 4010 Lassiter Mill Road,
respectively. The total acreage of the brownfield property is 7.18 acres.

The Brownfields Property is part of the North Hills complex that includes hotel, office, residential, shopping, dining, and entertainment venues in and about the former North Hills Mall.
Redevelopment Plans:
The redevelopment for this Brownfields Property is in the footprint where the former JC Penney Department Store, Ruth’s Chris Steakhouse, and associated parking were once located along Lassiter Mill Road. Redevelopment plans for the Brownfields Property include construction of a ten-story Class A office tower, a five-story mid-rise office
building, and a twelve-story residential apartment building with associated sub-grade
parking. Ground-level retail is planned for these buildings, with possible recreational and institutional uses. Site construction activities resulted in a large volume of soil (about 100,000 cubic yards)
being excavated and exported from the Brownfields Property. With the approval of the
Brownfields Program, some of this soil was accepted as imported fill material for the Seaboard Station (22075-19-092) and Raleigh MGP #2 (13022-09-092) Brownfield Properties and disposed of at Triangle Area Earth (NCDEQ Permit SRU600082) in Zebulon, North Carolina. Soil in Area 1A was sampled by advancing twenty borings and
collecting a single, discrete VOC sample from each boring. Sample aliquots, resulting in
10 feet (vertical) sample intervals were collected for SVOC and metals analysis. Soil in all other samples represented horizontal layers of soil. This soil was characterized in situ in order to evaluate the environmental risk and determine if this soil management approach was acceptable to the Brownfields Program.

Vapor intrusion mitigation system design plans for this Brownfields Property were approved by the Brownfields Redevelopment Section and a letter stating this was provided to the PD on December 29, 2021, prior to construction of the parking deck. The VIMS is comprised of chemical resistant barrier components only in the transiently
occupied spaces; in the commercial spaces, sub-slab soil gas depressurization is applied
in addition to MonoShield-based vapor intrusion mitigation. Vertical construction commenced April 2021 and occupancy of parking building P, and commercial buildings U, T, and Y are expected August 2023. Pre-occupancy sampling occurred in June 2023.
At the time of redevelopment, no DSCA wells remained on site. The following wells will
be installed: MW-13R, MW-13DR, MW-14R, and MW-15R. These wells will be replacements, as indicated by the “R” at the end of their ID and will be placed near the historical wells MW-13, MW-13D, MW-14, and MW-15, respectively.
Site History:
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Much of the site has been used for parking and commercial retail or restaurant space. The department store, JC Penny, an anchor tenant for the former North Hills Mall, formerly
occupied the site from the 1960s until it closed in 2020. Prior to the development of the
North Hills Mall, the Brownfields Property was undeveloped or was occupied by residential lots. Soil samples were collected for the site, on February 27, March 10, April 5
and 6, 2021. The results indicated that other than hexavalent chromium and arsenic, there
are no exceedances of any Residential Health Based PSRGs. The results indicated that the highest arsenic concentration (50.4 mg/kg) was collected at B-3; however, this may have been a false positive from using EPA Method 7196. When sampled using EPA Method 7199, the highest hexavalent chromium concentration was much less (1.1 mg/kg)
and was collected at B-4.
An indoor air sample was collected in the former Ruth’s Chris Steakhouse/Rodolfo Gonzales Interior Design building at 4381-105 Lassiter at North Hills, (Sample location IAS-1) on November 9, 2010, before it was demolished. While trichloroethylene (TCE),
tetrachloroethylene (PCE), and vinyl chloride were detected in this sample (0.438 J
micrograms per liter (µg/L), 0.367 µg/L, and 0.139 µg/L, respectively), none of the concentrations exceeded their respective Indoor Air Vapor Intrusion Screening Levels (IAVISLs). This building was demolished to make way for the new construction which included the installation of a VIMS; therefore, the past indoor air data would not be
applicable to the new construction.
Sources of contamination from the tenants operating at the North Hills Mall outside of the Brownfields Property footprint include known petroleum hydrocarbon contaminants from the Exxon Service Station and the Firestone Tire Center, and most notably, known
chlorinated solvent contamination from the former Brothers Cleaners previously located
at the northeastern extent of the North Hills area along Six Forks Road. A summary of these off-site areas is provided below:
Exxon Service Station
The Exxon Service Station, located approximately 350 feet northeast and upgradient of the Brownfields Property, which is still in operation, is the site of releases of petroleum hydrocarbon products that were first reported in 1998. Releases at the service station resulted in gasoline free product on the groundwater extending over a 120,000 ft2 area.
Associated impacts included gross contamination levels (GCLs) of benzene, toluene,
ethyl benzene, and xylenes (BTEX), and other dissolved-phase petroleum constituents in groundwater, and elevated soil gas concentrations. Contamination was addressed through the NC DEQ Underground Storage Tank (UST) Section by performing Aggressive Fluid Vapor Recovery (AFVR) events, and through the design and operation of an air sparge-
vapor extraction cleanup system. On May 15, 2015, DEQ UST Section issued a risk-
based Notice of No Further Action, subject to a Notice of Residual Petroleum for this site (UST Incident #20113). Contamination remains above groundwater quality standards
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(Title 15A NCAC 2L .0202) and residual contamination is still present in on-site soil in this area.

Firestone Tire Center The Firestone Tire Center was formerly located about 280 feet northeast from the Brownfields Property. It was the location of a 550-gal UST that contained used oil which was removed in 1996. The UST Section issued a NFA for the release from the 550-gallon
used oil UST on June 29, 2000 (Incident #33329). The NFA states that groundwater
quality standards are not met due to contamination, and the Firestone NFA is conditional. Brothers Cleaners Brothers Cleaners was a former dry cleaner site that was in operation from 1967 to the
late 1990s. It was located approximately 950 feet due north and upgradient of the
Brownfields Property. This Brothers Cleaners site was accepted into the NCDEQ Division of Waste Management, Superfund Section Dry-Cleaning Solvent Cleanup Act (DSCA) Program in 2002 (DSCA ID: DC920017). In 2003, building demolition occurred and about 450 tons of soil highly contaminated with chlorinated solvents, principally
PCE and TCE were removed from the area where the dry cleaner once stood. Residual
concentrations of contaminants stemming from this site in groundwater and soil gas exceed their respective NC 2L groundwater standards and VISLs. The plume of impacted groundwater and soil gas extends beneath the Brownfields Property. There is ongoing monitoring of groundwater by, the DSCA Program.

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, exterior soil gas, and sub-slab vapor. While soil was sampled for disposal purposes, this area was later excavated to a depth ranging from 10 feet to ~25 feet below ground surface (bgs) such that all available soil data represents soil that was removed
from the Brownfields Property except for one sampling location, HO-UST-PB. DEQ
relies on the site 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. Due to the revisions to the July 2023 risk calculator, and the contaminants of concern at the Brownfields Property, the January 2023 risk calculator provides an appropriate
evaluation of the risk posed by site contaminants. For the purposes of looking at the site
spatially, the risk calculator is based on site-wide assessment data. The first risk calculator output (Figure 1) below presents the results of the groundwater, soil, and sub-slab data. The second risk calculator output (Figure 2) represents the results of the
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exterior soil gas data. Subsequent to finalizing the draft BFA, we received pre-occupancy sub-slab vapor and indoor air data. This data is provided in the third risk calculator output
(Figure 3), below.
Figure 1. Groundwater, Soil, and Sub-Slab Vapor Risk Calculator Output

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Figure 2. Exterior Soil Gas Risk Calculator Output

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Figure 3. Site-Wide Maximum Pre-occupancy Sampling Sub-Slab and Indoor Air Vapor Risk Calculator Output

Figure 4. Pre-occupancy Sampling Sub-Slab and Indoor Air Vapor Risk Calculator Output by Exposure Unit

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Soil As discussed above, soil at the Brownfields Property was characterized in situ and largely
removed from the Brownfields Property. The cut depths in the excavation were about 10
feet below ground surface (bgs) in the blue area noted in the schematic below, and about 25 feet bgs in the red area (Figure 5). There is one sample location in the southwest portion of the Brownfields Property (HO-UST-PB), for which soil remains on site, and for which confirmatory soil testing was conducted on September 21, 2021 (Figure 1).
This sampling indicated no exceedances of residential PSRGs except for arsenic
concentrations at 1.59 milligrams per kilogram (mg/kg), which is typical of single-digit background arsenic concentrations in NC soil. Currently, the location of sampling is covered by a surface parking lot which is intended to be the site of a future building.
Groundwater
Groundwater was found at depths between 24.58 ft bgs and 45.45 ft bgs during the 2021 groundwater sampling efforts at the Brownfields Property. The direction of groundwater flow is to the south-southeast (Figure 6). On-site groundwater wells (MW-13, MW-13D, MW-14, MW-15, MW-15D) were sampled in May 2021, after which most of the wells
were abandoned to make way for the redevelopment. This recent sample data for the site
spanning from November 2, 2007, to present was reviewed and was used to generate the risk calculator output in Figure 1. The data was collected as part of the Brothers Cleaners (DSCA ID: DC920017) monitoring efforts. Mike Cunningham, DSCA Project Manager, confirmed on March 9, 2023, that May 2021 data is the most recent DSCA report for this
site. Groundwater contamination is due to historical dry-cleaning sources to the north and
upgradient of the Brownfields Property (Figure 7). General contaminant concentration trends indicate that the COCs are decreasing in concentration as time goes on. Consistent with DSCA’s request, wells MW-13, MW-13D, MW-14, and MW-15 will be replaced once construction has been completed in those areas.

For residential exposure scenarios, the risk calculator output shows that there are exceedances of the threshold non-carcinogenic hazard index (HI) of 1.0 for groundwater direct contact (HI of 3.1) and the groundwater to indoor air vapor intrusion pathway (HI of 2.8). The risk drivers for groundwater are PCE (Figure 3) and
dichlorodifluoromethane. Therefore, limitations on direct contact with groundwater are
included in the Land Use Restrictions of the Brownfields Agreement. The risk calculator output indicates that there is not an exceedance of the acceptable cancer risk (CR) range maximum of 1E-4 for neither direct residential nor non-residential
exposures to groundwater.
There are no identified groundwater receptors downgradient of the site within 500 ft of the Brownfields Property. Residents who live south of I-440 are likely all on municipal water and are some distance from the distal end of the known groundwater contaminant
plume.

Surface Water Surface water is not located on nor borders the Brownfields Property.
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Exterior Soil Gas
Three exterior soil gas samples (SG-5, SG-6, and SG-7) were collected in May 2021 in
the paved parking lot west of the former JC Penney Store at depths of approximately 20 ft bgs (Figure 2). For residential exposure scenarios, the risk calculator output shows that there is a slight
exceedance of the threshold noncancer HI of 1.0 with an HI of 1.1, with 1,3-butadiene
driving the risk. The source of this contaminant may be related to the off-site petroleum hydrocarbon releases, but it may also be related to a sampling artifact if not enough stabilization time was allowed between the installation of the sampling point and the collection of the sample. The presence of PCE and TCE in these exterior soil gas
samples, contributed to about 0.25 of the HI of 1.1.
For residential exposure scenarios, the risk calculator output shows that there is not an exceedance of the acceptable CR maximum of 1E-4.
Sub-Slab Vapor
For residential exposure scenarios, the risk calculator output (Figure 1) before the VIMS preoccupancy sampling for the soil gas to indoor air pathway indicates that there is an exceedance of the threshold noncancer HI of 1.0, at 9.6, which is higher than that calculated based on the groundwater to indoor air pathway of 2.8. PCE and TCE related
to the drycleaner plume drive the risk.
For residential exposure scenarios, the risk calculator output for the soil gas to indoor air pathway indicates that there is not an exceedance of the acceptable cancer risk range maximum of 1E-4.

Site-wide pre-occupancy sub-slab data was collected at the Brownfields Property on June 14, 2023. Using the maximum concentrations of contaminants detected site-wide, for residential exposure scenarios, the risk calculator output (Figure 3) shows that there is an exceedance of the acceptable HI of 1 for the soil gas to indoor air pathway (HI of 1.8).
The risk drivers are tetrachloroethylene (HI of 1.0) and 1,2-dichloropropane (HI of 0.46).
Threshold risk criteria were not exceeded for nonresidential exposure pathways. Pre-occupancy sub-slab residential exposure scenarios risk calculator output for the soil gas to indoor air pathway indicates that there is not an exceedance of the acceptable
cancer risk range maximum of 1E-4.
Importantly however, when the pre-occupancy sampling data are separated by exposure units (EUs), a summary of which is provided in Figure 4, there is only one EU which has an exceedance of the acceptable HI of 1 (EU5, with a HI of 1.2). EU5 refers to the
Building Y area with stairwells. The risk drivers for this calculation are trans-1,2-
dichloroethylene (trans-1,2-DCE) and xylenes.

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Indoor Air Indoor air sampling was not conducted as part of the 2021-2022 Brownfield Property
assessment effort, although one sample was collected at one of the former buildings in
November 2010. A VIMS system is installed at this facility and pre-occupancy sampling data were collected June 10, 2023, at the Brownfields Property. Using the maximum concentrations of contaminants detected site-wide (Figure 3), for
residential exposure scenarios, the risk calculator output shows that there is an
exceedance of the acceptable HI of 1 for the residential exposure of indoor air (HI of 6.3). The risk drivers are trans-1,2-dichloroethylene (HI of 2.1), naphthalene (HI of 1.6) and xylenes (HI of 1.4).
Importantly, however, when the pre-occupancy indoor air sampling data are separated by
EUs, as summarized in Figure 4, there are three EUs which have an exceedance of the acceptable HI of 1 for residential exposures (EU2, EU3, and EU5, with HIs of 2, 1.1, and 4.2, respectively). EUS, EU3, and EU5 represent the electrical room, southern storage area, and the Building Y with stairwells, respectively, none of which represent residential
areas in the building though the stairwell can connect nonresidential to residential spaces.
None of the HIs for these EUs exceed the threshold value of 1 for nonresidential exposure pathways. Further, the indoor air HI is greater than the sub-slab soil gas to indoor air pathway HI for
all three of these EUs, leading us to conclude that the exceedances of the threshold HI of
1 in indoor air in these EUs are due to indoor air interferences from compounds related to construction or finishing products used in the building and not from vapor intrusion from below the slab. Post-occupancy sampling will help to confirm this conclusion.
No trichloroethylene (TCE) was found in the pre-occupancy indoor air samples and no
TCE was found in the sub-slab samples at EU2 and EU3. TCE was detected only in one EU a J value of 0.666 µg/m3 in the sub-slab sample collected at EU3. Pre-occupancy indoor air residential exposure scenarios risk calculator output indicates
that the cancer risk for residential indoor air was calculated at 1E-4, at the maximum
regulatory range of 1E-4. Land Use Restrictions: LURs will include the standard land use restrictions including approved land uses, land
use definitions, specific prohibitions, requirement for an EMP, prohibitions on
groundwater use, soil disturbance, and 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.
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Property Management Branch Issues: The Environmental Management Plan was approved on April 9, 2021. Redevelopment
activities are anticipated to be concluded in 2024. The approved Environmental
Management Plan Implementation Report for soil assessment was submitted on May 10, 2021, and the approved Environmental Management Plan Implementation Report for soil gas assessment was submitted on June 23, 2021.
Based on the information Dan Nielson of Mid-Atlantic Associates provided in his June
29, 2023 email, we responded via email on July 26, 2023, that we are not objecting to occupancy of the new buildings at the North Hills Expansion project (25008-21-092), contingent on receiving and approving the signed and sealed pre-occupancy testing report. The Post-Construction/Pre-Occupancy VIMS Report (Mid-Atlantic Associates,
Inc., August 9, 2023) was received on August 9, 2023. This report has been reviewed and
is in the process of being approved; an occupancy letter will be provided shortly. VIMS post-occupancy testing is to be conducted after redevelopment activities conclude. This testing shall be conducted in compliance with the VIMP that was approved on
December 29, 2021.

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Figure 5. Map of soil that has been removed from the site, as presented in email from Jason Green, RE: [External] RE: Site boundary and sample location confirmation for the
North Hills Expansion (25008-21-92) Brownfields Property (Brasfield & Gorrie, L.L.C.,
January 27, 2023)

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Figure 6. Groundwater gradient map and historical sampling locations from Groundwater Monitoring Report Brothers Cleaners (Hart and Hickman, March, 4, 2022)

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Figure 7. Groundwater PCE Isoconcentration Map from Groundwater Monitoring Report Brothers Cleaners (Hart and Hickman, March, 4, 2022)