25077_Raleigh Ice Center_DM_20231113

DECISION MEMORANDUM
DATE: November 13, 2023
FROM: Stephanie Graham
TO: BF Assessment File
RE: Raleigh Ice Center
912 Hodges Street
Raleigh, Wake County
BF # 25077-21-092
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than high -density residential, retail,
restaurant, brewery, office, recreational, open space, 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 BIN -Hodges LLC, located at 500 E. Morehead Street,
Suite 200, Charlotte, NC 28202, and its manager is Beacon GP LLC whose representative
is Jon L. Morris of the same address.
The Brownfields Property consists of a 13.28-acre parcel identified by parcel
identification number (PIN) 1715117286 with associated address 912 Hodges Street,
which also formerly included the addresses 1042-1090 Mills Street. The Brownfields
Property is developed with a single -story commercial building that was used as a former
ice-skating rink, asphalt -paved surface parking lots, a gravel parking lot used for truck
trailer parking (leased to UPS), a wetland area, a portion of a surface water pond and
wooded land. The commercial building is unoccupied.
Redevelopment Plans:
The existing building will be demolished, and the PD plans to redevelop the property
with two high -density residential buildings that include approximately 400 units and
associated parking. Based on the DEQ risk calculator output that includes a calculated
exterior soil gas hazard index of 3.0, a vapor intrusion mitigation system (VIMS) will be
required.
In addition, methane gas is present onsite above the Brownfields 30% by volume (bv)
threshold, with low but measurable pressures within the planned building footprint as
well as outside the footprint within 50 feet of the western proposed building. Additional
methane testing is required, and the testing will need to be conducted over different
seasons.
Site History:
Previous uses of the Brownfields Property include undeveloped land (at least 1938 to
1978), entertainment venue and night clubs (1979 to 2001), an ice-skating rink (200 1 -
Raleigh Ice Center/25077-21-092/13November2023

2020), an outdoor hocky rink and lacrosse field (2000s to 2010s), a construction
equipment storage yard (2010s) and semi -truck trailer parking (2021 to 2022).
Crabtree Creek, which forms the northern boundary of the Brownfields Property located
north of Hodges Street, previously flowed onto the northwestern portion of the site. The
creek was re-routed to its current location, and the former onsite channel was filled
between 1971 and 1973. Although the fill material used in the channel is unknown, wood
debris was identified in a soil boring advanced in the area of the former channel in 2011.
This wood debris was present at 13 to 15 feet below ground surface (bgs).
Portions of the Brownfields Property were filled with 10 to 15 feet of soil, wood, inert
debris and other unknown material. To maintain the structural integrity of this fill,
retaining wall systems (block and anchor) were reportedly installed on the western portion
of the site. It is not clear if this fill was only placed in the former creek channel. In the late
1990s/early 2000s, additional fill material from construction sites located in downtown
Raleigh was brought onto the Brownfields Property and placed in the area east of the
building for an expansion pad. It is likely that at least a portion of this fill included
construction/demolition debris. A geotechnical boring, advanced on the east -central
portion of the site in 2011, identified the presence of asphalt at a depth of 6 to 8 feet bgs.
Potential Receptors:
Potential receptors include future onsite residents, visitors, onsite workers, construction
workers and trespassers.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
groundwater, sub -slab soil vapor, exterior soil gas, methane, 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. 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
hops://deq.nc. og_y/permits-rules/risk-based-remediation/risk-evaluation-resources.
For the purpose of looking at the site spatially, the site was addressed as a whole but
distinguishes between exterior soil gas and sub -slab soil vapor samples. In addition, two
risk calculators using sediment and surface water sample results for each of the onsite
pond and wetland area were performed. The first risk calculator below includes soil,
groundwater and sub -slab vapor. The second risk calculator is based only on the exterior
soil gas results, which allows for a comparison of the risk associated with sub -slab soil
vapor verses that based on exterior soil gas results only. The remaining risk calculators
were completed for surface water and sediment located in the southern pond and
northeastern wetland area.
Below is the risk output for the soil, groundwater and sub -slab vapor samples collected
across the site.
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Risk for Individual Pathways 1
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 25077-21-092
Exposure Unit ID: Sitewide Soil, GW and Sub -slab Vapor
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carciinogenic
Ri
Hazardindex
Risk exceeded?
Resident
Soil
8.0E-06
1.2E-01
NO
Groundwater Use*
4.8E-04
2.6E+01
YES
Non -Residential Worker
Soil
1.2E-06
9.6E-03
NO
Groundwater Use*
9.8E-05
4.0E+00
YES
Construction Worker
Soil
4.6E-07
9.0E-02
NO
Recreator/Trespasser
Soil
4.5E-06
6.7E-02
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carciin kenic
Ri
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
5.5E-06
1.3E+00
YES
Soil Gas to Indoor Air
3.2E-07
8.1E-01
NO
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
1.3E-06
3.1E-01
NO
Soil Gas to Indoor Air
2.5E-08
6.4E-02
NO
Indoor Air
NC
NC
NC
Soil
Risk values for soil collected across the Brownfields Property did not exceed the
regulatory carcinogenic threshold criteria nor a noncancer hazard index of 1.0. Soil data
was collected on the Brownfields Property in 2011, 2021 and 2022 from depths of 0-2
feet to 23 feet bgs. The soil data was obtained from 14 samples, including one duplicate
and one, three aliquot composite samples. Both arsenic and hexavalent chromium were
detected in onsite soils above their respective DEQ Preliminary Soil Remedial Goals
(PSRGs) for residential land uses.
Groundwater
The sitewide risk calculator summary output above indicates that the maximum
acceptable regulatory carcinogenic risk range of lE-4 is exceeded for the direct
residential pathway for groundwater use; however, no additional carcinogenic risk
exposure pathways were exceeded. The non -cancer hazard index threshold of 1.0 is
exceeded for direct residential and non-residential worker groundwater exposure
pathways. Arsenic, cadmium, mercury and barium concentrations in groundwater are
driving the risk for the direct groundwater exposure calculation; arsenic, mercury,
cadmium and barium drive the risk for non-residential direct groundwater use.
The calculated vapor intrusion risk output indicates that the non -cancer hazard index
threshold of 1.0 is exceeded for the residential groundwater to indoor air exposure
pathway. Mercury drives the risk for the calculated residential groundwater to indoor air
risk.
Groundwater data was collected on the Brownfields Property in 2011, 2021 and 2022
with 12 samples, including one duplicate, collected from 11 temporary monitoring wells.
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The wells were advanced in areas of potential fill material, the proposed eastern building
footprint, the undeveloped wooded area on the eastern portion of the site and the portion
of the property located north of Hodges Street. The onsite groundwater results identified
concentrations of volatile organic compounds (VOCs) and metals in excess of their
respective NC 2L groundwater standards. Methyl tert-butyl ether groundwater
contamination exceeds the Residential Vapor Intrusion Screening Levels (VISLs) for this
VOC in groundwater, and various additional contaminants detected do not have
established residential VISLs.
Sub -Slab Vapor
The soil gas to indoor air calculated risk values based on sub -slab vapor indicate a
noncancer hazard index of 0.81. While this hazard index is below the threshold of 1.0,
vapor intrusion guidance indicates that a system is recommended but is not required. The
PD has elected to install a VIMS system, which will be subject to pre- and post -
occupancy testing based on DWM guidance.
Three sub -slab vapor samples were collected on the Brownfields Property in 2020 and
2021. These samples were collected from below the existing slab using vapor pins into 1-
L Summa canisters. Acrolein exceeded its residential VISL for soil vapor. Other
compounds detected in the sub -slab vapor samples include acetone, 1,3-dichlorobenzene,
ethanol and trichlorofluoromethane, but there are no established VISLs for these
compounds.
Indoor Air
Indoor air samples were not collected in the Brownfields Property building; however, the
existing building will be demolished prior to redevelopment.
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Below is the risk output for the exterior soil gas samples collected across the site to
distinguish the output from those results based on sub -slab vapor data.
Risk for Individual Pathways
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 25077-21-092
Ex sure Unit ID: Exterior Soil Gas
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Construction Worker
Soil
NC
NC
NC
Recreator/Trespasser
Soil
NC
NC
NC
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
CarcinogenicRisk
I3azardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
4.5E-05
3.0E+00
YES
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
3.4E-06
2.4E-0.1
t NO
Indoor Air
NC
NC
I NC
Exterior Soil Gas
The Exterior Soil Gas risk calculator summary output indicates that the non -cancer
hazard index threshold of 1.0 is exceeded for the residential exposure pathway for vapor
intrusion. This threshold is not exceeded for the non-residential worker exposure
scenario. The carcinogenic risk of lE-4 is not exceeded for the residential or non-
residential worker exposure pathways.
The concentrations of benzene, ethylbenzene, xylenes, 1,3-butadiene, acrolein and
1,1,2,2-tetrachloroethane drive the risk for the calculated soil gas to indoor air value. The
non -cancer hazard index of 3.0 is based on these and other compounds, and the
Brownfields Redevelopment Section will require a VIMS for residential use. The PD
plans to install the VIMS to control potential vapor intrusion. Pre -occupancy and post -
occupancy sampling will be required.
In March 2021 (Phase I and II ESA Commercial Property, Hart & Hickman, 6/21/2021),
four exterior soil gas (SG) samples (SG-1 through SG-4) were installed 5.5 to 6 feet bgs
in known fill areas south and east of the building (SG-1 and -2), and in the central portion
of the site in previous areas of elevated VOC groundwater contamination (SG-3 and -4).
Multiple additional borings were advanced on the eastern portion of the site to collect
exterior soil gas samples within the footprint of the proposed high density residential
building; however, due to the presence of water or saturated soils, no exterior soil gas
samples could be collected in this portion of the Brownfields Property.
Raleigh Ice Center/25077-21-092/13November2023

In November 2021 (Supplemental Vapor Intrusion Assessment Report, Hart & Hickman,
3/18/2022), five additional exterior soil gas samples were collected to further evaluate the
onsite vapor concerns. These samples were collected in the central portion of the site
(SG-3A and SG-4A) and near the eastern proposed residential building (SG-25, SG-26
and SG-28).
Acrolein, benzene, 1,3-butadiene, ethylbenzene, 1,1,2,2-tetrachloroethane and total
xylenes were detected above their respective residential VISL. Other compounds
identified include acetone, 1,3-dichlorobenzene, dichlorotetrafluoroethane, ethanol, 4-
ethyltoluene, n-octane, trichlorofluoromethane and 2,2,4-trimethylpentane; however,
residential VISLs have not been established for these compounds. Redevelopment plans
have not yet been provided; therefore, it is unknown if any of the soil gas samples were
placed in areas of planned stairwells or elevator shafts; however, these will be targeted
areas for VIMs performance testing.
Methane
The risks of methane at a property are not incorporated into the DEQ risk calculator.
Therefore, Brownfields uses a protocol and threshold criteria where methane has been
detected on Brownfields sites.
In March/April 2021, methane samples were collected on the Brownfields Property from
the two sub -slab vapor (SSV) sample locations (SSV-1 and SSV-2), four exterior soil gas
sample locations (SG-1 through SG-4) as well as six additional sampling locations. Due
to the nature of SSV samples, these locations do not meet the minimum 5-foot sampling
depth requirement in the methane assessment protocol. In addition, the methane sampling
from SG-1 through SG-4 locations were collected after the leak checks were completed
and following the approximately 10-minute soil gas sampling period. The potential exists
that the methane concentrations may have bled off, prior to the methane sampling.
In November 2021, additional methane samples were collected from location SSV-3 (this
location does not meet the 5-foot depth requirement), exterior soil gas locations SG-3A,
SG-4A and SG-25 through SG-28 as well as 16 additional sampling locations within and
adjacent to the planned western residential building footprint. These samples were
collected the day prior to the soil gas sampling (based on sample dates), and two to three
days following the soil gas sampling event. Debris or organics were identified in methane
screening borings SG-11 (14-15 ft), SG-15 (3.25-11 ft), SG-16 (11-11.5 ft), SG-19 (7.5-8
ft), SG-20 (7-7.5 ft) and SG-33 (3.5-11 ft). The most significant debris was observed in a
suspected fill area located east-southeast of the existing commercial building. In addition,
wood debris was documented in exterior soil gas boring SG-2 during the March 2021
sampling event.
During the November 2021 methane sampling, two pressure and two landfill gas
measurements were collected at each sample location, with the exception of samples SG-
4A, SG25 and SG-28. Groundwater was encountered during the second sampling event at
these locations, and a second round of pressure/gas measurements could not be obtained.
Nested monitoring points were attempted at 5, 10 and 15 feet bgs in the sample locations;
however, due to refusal, groundwater or borehole collapse, samples from all three depths
were only collected from four locations (SG-10, SG-12, SG-15 and SG-33). Eight
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locations included sampling at approximately 5 and 10 ft bgs (SG-11, SG-14, SG-16, SG-
17, SG-18, SG-19, SG-21 and SG-22), and eight locations included sampling at only 5
feet bgs (SG-3A, SG-4A, SG-13, SG-23, SG-24, SG-25, SG-26 and SG-28).
During the 2021 methane sampling events, methane was detected in excess of the lower
explosive limit (LEL) of 5% in 10 boring locations. The methane may be the result of the
fill materials brought onto the Brownfields Property.
Additional methane sampling, including that to evaluate the impact of seasonal variation,
will be required following the removal of any unsuitable geotechnical fill, and methane
mitigation measures will be evaluated by a contractor that meets the specific
qualifications under the Brownfields methane guidance prior to occupancy of the planned
buildings.
Below is the risk output for the surface water and sediment samples collected from the
pond located on the southern portion of the site.
Risk for Individual Pathways
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 25077-21-092
Ex sure Unit ID: Southern Pond- Surface Water/Sediment
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Soil
3.9E-06
TOE-02
NO
_____ ___
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
6.0E-07
5.6E-03
NO
Groundwater Use*
NC
NC
NC
Construction Worker
Soil
2.2E-07
4.7E-02
NO
Recreator/Trespasser
Soil
2.2E-06
3.7E-02
NO
____
Surface Water*
4.7E-06
8.7E-02
NO
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
The Southern Pond risk calculator summary output indicates that neither the maximum
acceptable carcinogenic risk of lE-4 nor the non -cancer hazard index regulatory
threshold of 1.0 is exceeded for direct residential, non-residential, construction worker,
nor recreation/trespasser exposure pathways for soil, which in this case represents
sediment in the pond. Additionally, the carcinogenic risk and the non -cancer hazard index
thresholds are not exceeded for the direct surface water exposure pathway.
Below is the risk output for the surface water and sediment samples collected from the
wetland area located on the northeastern portion of the site.
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Risk for Individual Pathways 1
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 25077-21-092
Exposure Unit ID: Northeastern Wetland Area - Surface Water/Sediment
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carciinogenic
Ri
Hazardindex
Risk exceeded?
Resident
Soil
1.1E-05
2.2E-01
NO
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
2.0E-06
1.7E-02
NO
Groundwater Use*
NC
NC
NC
Construction Worker
Soil
5.5E-07
1.5E-01
NO
Recreator/Trespasser
Soil
6.2E-06
1.2E-01
NO
Surface Water*
2.7E-06
4.7E-02
NO
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carciin kenic
Ri
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
_
NC
NC
NC
The Northeastern Wetland Area risk calculator summary output indicates that neither the
maximum acceptable carcinogenic risk of 1E-4 nor the non -cancer hazard index
regulatory threshold of 1.0 is exceeded for direct residential, non-residential, construction
worker, nor recreation/trespasser exposure pathways for soil, which in this case
represents sediment in the wetland area. Additionally, the carcinogenic risk and the non -
cancer hazard index thresholds are not exceeded for the direct surface water exposure
pathway.
Land Use Restrictions (LURs):
The Brownfields Agreement will include the standard LURs regarding land uses, the
requirement for an approved Environmental Management Plan (EMP), redevelopment
reporting, prohibitions on groundwater use, restrictions on soil disturbance, no soil
import/export without DEQ approval, known contaminant uses, notification, access,
vapor intrusion and LUR update provisions.
Based on the site -specific data provided to the Brownfields program, the site reuse is
suitable as long as the agreed upon land use restrictions in the BFA are abided by.
Property Management Issues:
Based on the exterior soil gas hazard index of 3.0, a VIMS is required. A VIMS design
has not yet been provided to Brownfields. The construction start date is unknown, and an
EMP has not been provided for review.
Email correspondence from DEQ BRS to the PD team on April 12, 2022, stated that once
the fill material that is not geotechnically suitable has been excavated to the applicable
depth (which may contain at least some of the material responsible for the methane
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readings), methane samples, under an approved workplan, will be required at the base of
the excavation, as well as the evaluation of seasonal variability. It is unknown if the
excavation of this material will remove any methane generating fill and/or eliminate the
need for methane mitigation.
If elevated methane remains, the methane work, including mitigation activities, must be
completed by an approved consultant that has the qualifications to design and
successfully implement the methane system. The VIMS can be designed to mitigate both
VOCs and methane. Final grade, pre -occupancy and post -occupancy sampling will be
required.
Based on the proposed continued use as a parking lot, methane assessment was not
completed on the northwestern portion of the Brownfields Property (north of Hodges
Street). Prior to construction of any future buildings in which the construction type does
not eliminate a potential methane concern, methane assessment is required on this
northwestern portion of the Brownfields Property.
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