25087_Hammond Center_DM_20230801

DECISION MEMORANDUM
DATE: August 1, 2023
FROM: Shristi R. Shrestha
TO: BF Assessment File
RE: Hammond Center Drive
100, 101, and 120 Hammond Center Drive
Raleigh, Wake County
BF # 25087-21-092
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 rental residential, office,
retail, recreational, parking uses, and subject to DEQ prior written approval, other
commercial uses, can be made suitable for such uses.
Introduction:
The Brownfields Property Application (BPA) was submitted on October 15, 2021, under
the former address of 100 Knowles Street, Raleigh. The Prospective Developer (PD) is
Maple Multi -Family Development Land SE, L.P., a limited partnership with its principal
office located at 4509 Creedmoor Rd, Suite 308, Raleigh, NC 27612. The Vice President
for the PD is Robert H. Brooks, and the contact person is Mark Mathews.
The Brownfields Property is comprised of three parcels totaling 35.77 acres: 100
Hammonds Center (PIN 1702772682), 10.05 acres, 101 Hammonds Center Drive (PIN
1702668490), 10.03 acres and 120 Hammonds Center Drive (PIN 1702677491),15.60
acres. The current property owner is CH-AFH I/Raleigh downtown south LLC located at
4509 Creedmoor Rd Suite 308, Raleigh NC 27612.
Redevelopment Plans:
The PD plans to redevelop the property into a multi -family apartment community. Final
redevelopment plans are complete and were submitted in June 2023. The apartment count
will not exceed 350. The application states that the apartment community will include
generous amount of green space for recreational use of the residents.
Due to the detection of trichloroethene (TCE) in two of the exterior soil gas samples in
excess of its Residential Vapor Intrusion Screening Level (VISL) under the future
footprint of two of the three planned buildings and near or within the planned utility
corridor, DEQ has highly recommended that the PD install a Vapor Intrusion Mitigation
System (VIMS) in accordance with our VIMS design checklist. The PD submitted a
VIMS design on March 6, 2023.
Hammond Center Drive/25087-21-092/20230801

Site History:
The Brownfields Property was agricultural, wooded and undeveloped land in 1938. From
1949 to 1968, a pond named Parker Pond was located on the southern portion of the
Brownfields Property. A structure was also present along the semi -circular roadway on
the along the northwestern boundary in the early 1970s. The pond on the southern portion
appeared to be drained or reduced in size by 1973, with only a small pond along the
southwestern boundary. There is no indication that the Brownfields Property itself was
ever developed with structures, although recent observations indicate dumping of trash
and household debris at the end of Hammond Center Drive
A stream, Wildcat Branch, runs through the Brownfields Property near the eastern
boundary. Two monitoring wells were installed in 2009 on the Brownfields Property in
the northeastern area, west of Wildcat Branch. The monitoring wells were installed
related to contamination identified from the Raleigh Metals property located east of
Hammond Road. Raleigh Metal Recycling, or its predecessors, have been located to the
east of the property since the early 1950s, prior to the development of Hammond Road.
In the site vicinity, commercial and industrial properties are located to the north, such as
International Paper (now Evergreen Packaging) and Winn Dixie (now UPS) were
developed adjacent to the northwest and farther north in the mid- 1950s and expanded in
the 1980s and 1990s. The residential neighborhood to the west has been present since the
mid-1960s.
Potential Receptors:
Potential receptors are construction workers, on -site workers, future residents, and
trespassers.
Contaminated Media:
DEQ has evaluated data collected from the following media at the Brownfields Property:
soil, groundwater and exterior 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).
Risk Calculations:
Risk calculations were performed using the January 2023 DEQ Risk Calculator
https:Hdeg.nc. goy/permits-rules/risk-based-remediation/risk-evaluation-resources.
For the purposes of looking at the site spatially, the site was evaluated as a whole.
The risk calculations indicated the following based on available data, including the
following media: soil, groundwater and exterior soil gas samples.
2
Hammond Center Drive/25087-21-092/20230801

Risk for Individual Pathways M
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 25087-21-092
Exposure Unit ID: Site wide (Soil, GW & Soil as)
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carciinnsogenic
Hazard Index
Ri sk exceeded?
Resident
Soil
7.0E-06
8.0E-02
NO
Groundwater Use*
1.3E-04
2.6E+00
YES
Non -Residential Worker
Soil
7.6E-07
5.7E-03
NO
Groundwater Use*
2.8E-05
5.2E-01
NO
Construction Worker
Soil
4.8E-07
5.7E-02
NO
Recreator/Trespasser
Soil
3.9E-06
4.4E-02
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Ri sk exceeded?
Resident
Groundwater to Indoor Air
2.5E-06
3.8E-01
NO
Soil Gas to Indoor Air
1.0E-05
8.8E-01
NO
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
4.8E-07
9.1E-02
NO
Soil Gas to Indoor Air
7.3E-07
7.0E-02
NO
Indoor Air
NC
NC
NC
The risk calculator output shows that the noncancer hazard index (HI) for resident direct
groundwater use exceeds the regulatory threshold of 1, and the acceptable cancer risk
range of 1.0E-04. The soil gas to indoor air calculated HI is 0.88; although this does not
exceed the threshold HI of 1, this value is based on exterior soil gas samples only. Further
because TCE was detected in excess of its Residential VISL in exterior soil gas samples
near planned utility corridors, we are concerned, as we have seen at other sites, that
although the calculated soil gas to indoor air risk value at 0.88 is less than 1.0, that the
construction of the buildings on the Brownfields Property, especially the two southern
buildings will change site conditions creating areas in which TCE migration along
preferential pathways or accumulation of vapors in sub -slab areas may pose a risk of
vapor intrusion into the living space. Therefore, we have recommended that a vapor
intrusion mitigation system (VIMS) be designed and installed for these buildings.
Soil
The soil samples were collected with direct push techniques using disposable soil liners
placed within the dual tube soil sampler. The samples depth range was from ground
surface to depth ranging from 10-25 ft bgs. No soil import or export has been done to or
from the Brownfields Property at this time; any future import or export will be done
under an approved Environmental Management Plan (EMP). Only arsenic and hexavalent
chromium concentrations in site soils exceeded their respective January 2023 North
Carolina Department of Environmental Quality (NCDEQ) Inactive Hazardous Waste Site
Branch (IHSB) Preliminary Soil Remediation Goals (PSRGs). However, calculated risk
values indicate that compounds in soil at the Brownfields Property do not exceed the
acceptable risk thresholds for any soil exposure scenario as noted in the risk output
above.
Hammond Center Drive/25087-21-092/20230801

Groundwater
Based on the environmental assessment done at the Brownfields Property, the
groundwater flow is anticipated to be towards the east to Wildcat Branch. The depth of
groundwater encountered at the Brownfields Property was from 2.4 ft bgs to 6.7 ft bgs.
Groundwater will not be used as a water supply for this site and a land use restriction will
further prohibit its use. The hazard index was exceeded in resident groundwater use due
to the presence of compounds like Arsenic, Cadmium, Naphthalene and
Trichloroethylene.
Surface Water
Surface water was not sampled at the Brownfields property.
Exterior Soil Gas
Exterior soil gas samples were collected at the Brownfields Property without the
Brownfields Program's input or approval prior to applying to the Program. During the
Phase II assessment of the Brownfields Property exterior soil gas samples that were
collected on October 16, 2021, were not collected in accordance with our VI assessment
protocols. The final vacuums in the Summa canisters were below the recommended
limit. Hence, the exterior soil gas samples were collected again in August 2022, and the
results from the previous soil gas assessment were disregarded, and not used in the
preparation of Exhibit 2 or the risk calculators.
TCE and 1,3-butadiene were detected in exterior soil gas samples in excess of their
respective Residential VISLs. There were several other contaminants detected, acetone,
dichlorodifluoromethane (Freon 12), ethanol, and 4-ethyltoluene were also detected, but
there are no established screening levels for these compounds.
The main drivers of risk for the calculation of the soil gas to indoor air vapor intrusion
risk scenario is the presence of primarily TCE in samples UCSV-Ul, located near a
utility line, and UCSV-B 1, located under the future building footprint, at 39 and 38
µg/m3, respectively and 1,3-butadiene at 20 µg/main sample UCSV-U2. As discussed
above, based on the toxicology of TCE, the fact that these detections were in exterior soil
gas near planned utility corridors, there is uncertainty as to the impact that the
construction of these residential structures may have on the potential for vapor intrusion
into the buildings. Therefore, it is highly recommended that a VIMS system be placed
under at least the two southern buildings on this Brownfields Property. and the samples
UCSV- B 1 are located under two of the future building footprints.
Vapor intrusion risk will be addressed through the VI land use restriction in the
Brownfields Agreement.
Indoor Air
No buildings have been constructed as of yet; hence this is not applicable.
4
Hammond Center Drive/25087-21-092/20230801

Land Use Restrictions:
The land use restrictions at the property will include the typical land use restrictions
related to approved land uses, no physical redevelopment without an EMP,
redevelopment reporting, restrictions on groundwater use, soil disturbance and fill/export
of soil, final grade sampling, known contaminant uses, notices, access, deed, and land use
restriction update provisions.
Based on the site -specific data provided to the Brownfield Redevelopment Section, the
site reuse is suitable for the site if the agreed upon land use restrictions in the BFA are
abided by.
PROPERTY MANAGEMENT ISSUES: The Brownfields Property is currently
undeveloped. Construction was originally slated to being in April 2023, but has been
delayed. A redevelopment plan was submitted on 6/27/2023. A VIMS system design
system submittal was done by PD on March 6, 2023. VIMS design was approved, and the
letter was sent out on 7/19/2023.
Post -recordation issues are expected to include performance monitoring of the VIMS and
final grade sampling.
Hammond Center Drive/25087-21-092/20230801