25097_Eno Industrial_DM_20231114

DECISION MEMORANDUM
DATE: November 14, 2023
FROM: Shristi R. Shrestha
TO: BF Assessment File
RE: Eno Industrial Park
1420 Old Oxford Road
1225, 1507, & 1539 Hamlin Road
Durham, Durham County
BF # 25097-21-032
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than industrial, office, warehousing, parking,
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 November 15, 2021.
The Prospective Developer (PD) is Welcome Venture Park LLC, a limited liability
company with its principal office located at 5858 Westheimer Road, Suite 800, Houston,
Texas 77057. The entity manager for the PD is Ted Kakambouras and the contact person
is Randy Warren. The president for the PD is Welcome Wilson Jr. who is also the signing
official.
The Brownfields Property originally consisted of four parcels totaling about 160.731
acres: 1420 Old Oxford Road (Parcel ID 177731) about 7.81 acres, 1225 Hamlin Road
(Parcel ID 236462) at about 49.27 acres, 1507 Hamlin Road (Parcel ID 236464) at 46.21
acres, and 1539 Hamlin Road (Parcel ID 236463) at about 58.40 acres. The PD has
purchased the property since the application was submitted. The land is currently vacant
and is zoned for industrial use.
Redevelopment Plans:
The PD plans to redevelop the land into non-residential light industrial and office use
with paved parking and landscaped areas around the buildings. A portion of the
Brownfields Property to the southwest was suspected to have been impacted from an off -
site volatile organic compound (VOC) plume from the former Mitsubishi Electronics site.
Phase II and additional site assessment in the area where the new buildings are planned
indicated that those detections were outside the footprint of the planned buildings. Hence,
it was concluded that there is no need for a vapor intrusion mitigation system.
Site History:
The Brownfields Property is currently vacant and is covered with vegetation with no
commercial development occurring historically other than tobacco farming and older
Eno Industrial Park/25087-21-032/20231114

residential structures. There are several streams, ponds and wetland areas on the
Brownfields Property.
Surrounding area properties are classified as industrial. Immediately to the southwest is
the former Mitsubishi Electronics facility (NC DEQ Inactive Hazardous Sites Branch
(IHSB ID No. NONCD0002085). This facility has a known chlorinated VOC issue in
soil, surface water, and in a groundwater plume consisting principally of
tetrachoroethylene (PCE) and its breakdown products, which have migrated to the
southernmost part of the Brownfields Property. IHSB continues to require monitoring of
the Mitsubishi wells, including those located on the Brownfields Property. The
Prospective Developer is required to replace monitoring wells MW-13, MW-14, MW-17,
MW-20 and MW-24 as required by the DEQ IHSB, in accordance with Subchapter 2C of
Title 15A of the North Carolina Administrative Code, and consistent with the locations
agreed to by DEQ, unless an alternate schedule is approved by DEQ.
Immediately to the east of the Brownfields Property is the combined Beckman Durham
and Chuck Sandefer residential site (NCN000410370), with known VOC contamination
in soil and groundwater that has impacted nearby potable water supply wells, and a
Durham County Public school site with a NC UST Section Leaking Underground Storage
Tank (USY Incident #7017). The direction of groundwater flow from these sites is
towards the eastern part of the Brownfields Property.
There was an area on the southwest part of 1225 Hamlin Road (parcel #236462) at the
Brownfields Property where an abandoned pole -mounted transformer was located. This
area was defined in the January 30th, 2023 Redevelopment Summary Report. During the
Phase I environmental site assessment, it was found to contain polychlorinated biphenyls
(PCB). Known remedial activities at the Brownfields Property included the removal of a
PCB -contaminated transformer on December 19, 2022, and 35.41 tons of soil deemed to
be impacted with PCBs. This was done according to a DEQ-approved EMP that was
executed on December 16, 2022.
Potential Receptors:
Potential receptors are construction workers, on -site workers, visitors, and trespassers.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
groundwater, sediment, surface water, 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://deq.ne. goy/permits-rules/risk-based-remediation/risk-evaluation-resources.
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For the purpose of looking at the site spatially, the site was evaluated as whole.
The risk calculations indicated the following based on available data, including the
following media: residual soil, groundwater, stream sediment, and exterior soil gas.
Sitewide risk calculator (excludes soil samples that represent soil removed that was
removed from the property)
Risk for Individual Pathways
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 25097-21-032
Exposure Unit ID: Sitewide Soil, groundwater, exterior soil as)
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded'.
Resident
Soil
1.8E-05
4.3E-01
NO
Groundwater Use*
2.2E-04
3.9E+00
YES
Non -Residential Worker
Soil
1.8E-06
3.1E-02
NO
Groundwater Use*
4.5E-05
6.6E-01
NO
Construction Worker
Soil
1.3E-06
1.6E-01
NO
Recreator/Trespasser
Soil
1.0E-05
2.4E-01
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
4.0E-06
5.6E-01
NO
Soil Gas to Indoor Air
1.5E-04
2.6E+00
YES
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
8.0E-07
1.3E-01
NO
Soil Gas to Indoor Air
1.1E-05
2.1E-01
NO
Indoor Air
NC
NC
NC
Eno Industrial Park/25087-21-032/20231114

Risk for Individual Pathways
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 25097-21-032
Ex sure Unit ID: Sitewide Sediment, groundwater, exterior soil as
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Soil
5.7E-06
1.4E-02
NO
Groundwater Use*
2.2E-04
3.9E+00
YES
Non -Residential Worker
Soil
2.7E-07
1.1E-03
NO
Groundwater Use*
4.5E-05
6.6E-01
NO
Construction Worker
Soil
4.9E-07
6.9E-03
NO
Recreator/Trespasser
Soil
3.2E-06
7.1E-03
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Riskexceeded?
Resident
Groundwater to Indoor Air
4.0E-06
5.6E-01
NO
Soil Gas to Indoor Air
1.4E-04
2.5E+00
YES
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
8.0E-07
1.3E-01
NO
Soil Gas to Indoor Air
1.1E-05
2.0E-01
NO
Indoor Air
NC
NC
NC
Soil
The soil samples were collected using stainless steel hand auger and a track -mounted
DPT drilling rig. The depth of soil samples was in the range of 0-20 ft below ground
surface (bgs). Soil that contained polychlorinated biphenyls (PCBs) and total petroleum
hydrocarbons were removed from the Brownfields Property. The calculated risk values
for soil 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.
Groundwater
The monitoring wells for the groundwater samples were installed at a depth range of 27-
85 ft bgs. The groundwater samples were collected according to NCBP approved work
plan. The contaminants which were detected above the 2L Groundwater Standards (April
1, 2022 version) were arsenic, barium, chromium, lead, and selenium. The risk for
resident groundwater use has been exceeded as can be seen in the risk calculator output
above. The main drivers for risk for this scenario were the presence of arsenic, barium
and selenium compounds. Groundwater will not be used for water supply purpose at this
nonresidential Brownfields Property, therefore this exposure pathway is not complete.
The monitoring wells that are located on the property for Mitsubishi site are MW-13,
MW-14, MW-17, MW-20 and MW-24. Data from these wells were taken into account
while running the risk calculator.
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Surface Water
Two surface water samples were collected at the Brownfields Property. A third location
was planned but it was dry at the time of sample collection. The risk calculator output did
not indicate exceedances of acceptable environmental risk threshold criteria based on
these data.
Sediment
Sediment samples were collected at the Brownfields property. None of the samples
exceed the Industrial/Commercial health based PSRG. Data from these points were
considered in the second risk calculator whose output is listed above. The output shows
that there isn't a significant difference when the sediment data was incorporated into the
risk calculator.
Exterior Soil Gas
Originally, 15 soil gas samples were collected during Phase II assessment work in
November 2021; however, this work was not approved by the Brownfields Program. An
additional 14 soil gas samples were collected in July 2022 in accordance with an NCBP
approved work plan. The risk calculator output shows that the environmental risk for
non -cancer hazard index for residential soil gas to indoor air has been calculated as 2.6,
which exceeds the regulatory threshold value of 1.
Contaminants that were detected above the screening levels were 1,3-butadiene and
chloroform. Other contaminants that were detected, but do not have established screening
levels were ethanol, 4-ethyltoluene, 1-octene and n-octane 2,2,4 trimethylpentane,
tricholorofluoromethane, trichlorotrifluoroethane, and dichlorodifluoromethane. The
main driver for the risk in this scenario was the presence of 1,3- butadiene. 1,3-butadiene
has been associated with sampling artifact when soil gas probes are not allowed to
properly stabilize prior to sampling. This is likely the reason why we see 1,3-butadiene
in these samples. Further, residential use is not planned at the Brownfields Property, so
this exposure pathway is not germane to the intended reuse of the Brownfields Property.
Sub -Slab Vapor
The Brownfields Property was vacant at the time of assessment; therefore, these types of
samples are not applicable.
Indoor Air
The Brownfields Property was vacant at the time of assessment; therefore, these types of
samples are not applicable.
Land Use Restrictions:
The Brownfields Agreement for this Brownfields Property will include typical land use
restrictions including approved uses, land use definitions, requirements for an EMP,
vapor intrusion, access notice and land use restrictions update LUR's.
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Based on the site -specific data provided to the Brownfield Redevelopment Section, 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 ISSUES
The Brownfields property is vacant and grading work started on April 10, 2023. Based on
assessment data and an evaluation of acceptable risk, there is no vapor intrusion
mitigation in the nonresidential buildings planned at the Brownfields Property. There are
no known property management issues at this time.
Any request for residential use of the Brownfields Property, or for buildings in closer
proximity to the VOC plume in the future would require additional vapor intrusion
evaluation.
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