23016_TW Alexander_DM_20191108

DECISION MEMORANDUM
DATE: November 8, 2019
FROM: Reina Clark & Sharon Eckard
TO: BF Assessment File
RE: TW Alexander -IBM
0 TW Alexander Dr., 0, 3102, 3204, 3252, 3268 S. Miami Blvd.
Durham, Durham County
BF # 23016-19-032
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than the construction of industrial flex
buildings, associated parking, and subject to DEQ's prior written approval, other
commercial uses, can be made suitable for such uses.
Introduction:
The Brownfields Property comprises six parcels, totaling 51.15 acres, and assigned Parcel
ID Numbers 0749-03-31-9242, 0749-03-41-4159, 0749-04-51-1176, 0749-04-50-1918,
0749-03-40-3468, and 0748-01-49-4407 by the Durham County Tax Administration
Office. These six parcels are currently owned by International Business Machine
Corporation (IBM). IBM purchased parcels 0749-03-31-9242, 0749-03-41-4159, 0749-
04-51-1176, 0749-03-40-3468, and 0748-01-49-440 on January 9, 1978 from Cullasaja
Company (recorded as Durham County Register of Deeds at Book 961, Page 347) and
parcel 0749-04-50-1918 (recorded as Durham County Register of Deeds at Book 1107,
Page 42) on March 3, 1983 from Mr. and Mrs. Dewey A. Briggs.
The parcels comprising the Brownfields Property have not been developed following
IBM's acquisition of the parcels, though certain of the parcels are reported to have had
single family residential dwellings historically. A stream named Stirrup Iron Creek runs
through a topographic low across the Brownfields Property from northwest to southeast.
Designated wetlands areas are also located on the Brownfields Property.
The Prospective Developer (PD) is Merritt — IB1, LLC, which has its principal office
located at 2066 Lord Baltimore Drive in Baltimore, Maryland 21244. The PD contact is
Robb Merritt whose principal office is located at 2066 Lord Baltimore Drive, Baltimore,
Maryland 21244. The PD is contractually obligated to purchase the Brownfields Property
within 30 days of a completed Brownfield Agreement.
Redevelopment Plans:
The PD intends to invest approximately $41.5 million to redevelop the site with four flex -
style buildings totaling 285,497 square ft designed for light industrial use as permitted by
a City of Durham zoning ordinance. Redevelopment is limited to areas outside the
wetland on the topographic ridges of the Brownfields Property.

Site History:
According to historical research documentation, past use of the Brownfields Property
includes agricultural and residential uses, although residential structures were removed
sometime between 1972 and 1981. The site was purchased by IBM between 1978 and
1983, but IBM did not construct any structures or facilities, or operate on the Brownfields
Property. Therefore, the site is primarily wooded and undeveloped.
Chlorinated solvents (1, 1, 1 -trichloroethane (1,1,1-TCA), 1,1,2-TCA, 1, 1 -dichloroethane
(1,1-DCA), 1,2-DCA, 1, 1 -dichloroethylene (1,1-DCE), 1,4-dioxane,
dichlorodifluoromethane, and vinyl chloride) have been documented at the Brownfields
Property in groundwater that has migrated to the site from an off -site solvent plume
associated with the former Edward Weck, Inc. (Weck) facility, located on a north
adjacent parcel, across TW Alexander Drive. Investigation of the Weck site is
documented in IHSB REC records (Project No. NCD001493931). Migration of
contaminated groundwater is influenced by a subsurface diabase dike.
Potential Receptors:
Potential receptors are: construction workers, on -site workers, visitors, animals, and
trespassers.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
groundwater, surface water, and soil gas. DEQ relies on the following data to base its
conclusions regarding the subject property and its suitability for its intended reuse.
Soil
Four soil samples were collected from one to six feet below ground surface in the
footprints of each of the four proposed flex warehouse structures to be developed at the
site and screened for the presence of volatile organic compounds (VOCs) using a
photoionization detector (PID). Of the four soil samples collected from each building
footprint, two were submitted for laboratory analysis of VOCs totaling eight soil samples
for VOC analysis. Remaining soil from the one- to six-foot sample interval was
homogenized and one composite soil sample from each of the proposed building
footprints were submitted for laboratory analysis of semi-VOCs (SVOCs) and RCRA
metals including speciated chromium totaling four soil samples for SVOC and RCRA
analysis. With the exception of acetone, VOCs and SVOCs were not detected above
laboratory method detection limits in soil samples collected. Arsenic, barium, chromium,
lead, mercury, and selenium were detected in one or more soil samples collected;
however, laboratory analysis did not indicate the presence of metals in soils at
concentrations exceeding their respective Industrial/Commercial Preliminary Soil
Remediation Goals (PSRGs), May 2019.
Groundwater
Groundwater quality on the north portion of the site has been assessed since 1993 in
response to the chlorinated solvent release originating on the north adjacent parcel

(NCD001493931). Since that time, benzene (1.1 micrograms per liter [ug/L]), carbon
tetrachloride (1.9 ug/L), 1,2-dichloroethane (1,2-DCA, 1.1 ug/L), 1,4-dixoane (9.3 ug/L),
1,1,2-trichloroethane (1,1,2-TCA, 0.62 ug/L), and vinyl chloride (0.2 ug/L) have been
detected in groundwater at the Brownfields Property at concentrations exceeding their
respective North Carolina Groundwater Quality Standards (NCGQS). In addition,
dichlorodifluoromethane (21.9-58 ug/L) and 1,1-dichloroethene (1,1-DCE, 190 ug/L)
have been detected at concentrations exceeding their Non -Residential Groundwater
Vapor Intrusion Screening Levels of 6.2 ug/L and 160 ug/L, respectively, in onsite wells
M-4-150, AD-50, and CW-4Dike.
Surface Water
Surface water quality has been assessed at the Brownfields Property from two sampling
locations, 9G1802 and SW-2 as part of the investigation of the contiguous Weck
Property. Chloroform, 1,1-DCE, dichlorofluoromethane, and 1,1,1-TCA have been
detected in surface water samples at concentrations exceeding laboratory method
detection limits, but below their respective applicable surface water standards.
Soil Gas Vapor
A total of 24 soil gas samples were collected from the footprints of the four proposed flex
warehouse structures to be constructed at the Brownfield Property. Multiple VOCs were
detected in each soil gas sample at concentrations exceeding laboratory method detection
limits, but below their respective Non -Residential Vapor Intrusion Screening Levels
(VISLs).
Risk Calculations
Risk Calculations were performed using the DWM Risk Calculator (May 2019 version).
For the purposes of looking at the site spatially, risk analysis of soil and soil gas data was
divided by proposed building footprints resulting in four risk calculators for soil and soil
gas. Groundwater quality was combined and interpreted as a cumulative site -wide risk
analysis. The risk calculations indicated the following based on available data, including
the following media: groundwater, surface water, soil, and soil gas samples:

Risk for Individual Pathways rel 1 W.
Version Date: May 2019
Basis: May 2019 EPA RSL Table
Site ID: TW Alexander Flex
Exposure Unit ID: Cummulative groundwater and surfacewater
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carc inogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Soil
0.0E+00
0.0E+00
NO
Groundwater Use*
4.9E-05
3.1E+00
YES
Non -Residential Worker
Soil
0.0E+00
0.0E+00
NO
Groundwater Use*
8.9E-06
7.0E-01
NO
Construction Worker
Soil
0.0E+00
0.0E+00
NO
Recreator/Trespasserr7
Soil
Surface Water*
0.0E+00
0.0E+00
NO
6.8E-08
3.8E-03
NO
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
8.3E-06
9.1E+00
YES
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
1.6E-06
2.2E+00
YES
Sort Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
The elevated detections of dichlorodifluoromethane have contributed to an exceedance of
risk for both residential and non-residential use with respect to groundwater to indoor air
vapor intrusion. In addition, the elevated concentration of 1,1,2-TCA has contributed to
an exceedance of risk for a residential scenario with respect to groundwater combined
pathways; however, groundwater use will be prohibited by the land use restrictions in the
Brownfields Agreement so there should be no direct contact with groundwater by onsite
uses and the property will be limited to non-residential use. Historical surface water
analytical data does not appear to pose an unacceptable risk to future site occupants.

Risk for Individual Pathways rel 1
Version Date: May 2019
Basis: May 2019 EPA RSL Table
Site ID: TW Alexander Flex Property
Exposure Unit ID: Building 1
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carc�skenic
Hazard Index
Risk exceeded?
Resident
Soil
2.1E_06
4.5E_02
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil
4.7E-07
3.4E-03
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Construction Worker
Soil
7.8E-08
3.6E-02
NO
Recreator/Trespasserr7
Soil
Surface Water*
1.2E-06
2.4E-02
NO
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
8.7E-06
1.8E-01
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Sort Gas to Indoor Air
6.3E-07
1.5E-02
NO
Indoor Air
0.0E+00
0.0E+00
NO
Soil and soil gas data collected from the footprint of proposed Building 1 (see attached
figure) were input to the May 2019 Cumulative Risk Calculator. The Risk Calculator
indicates that soil contaminants do not pose an unacceptable risk to construction workers
and/or future workers and soil gas contaminants do not pose an unacceptable vapor
intrusion risk to future workers of Building 1.

Risk for Individual Pathways rel 1
Version Date: May 2019
Basis: May 2019 EPA RSL Table
Site ID: TW Alexander Flex Property
Exposure Unit ID: Building 2
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carc�skenic
Hazard Index
Risk exceeded?
Resident
Soil
2.5E_06
5.1E_02
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil
5.7E-07
3.7E-03
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Construction Worker
Soil
9.4E-08
4.0E-02
NO
Recreator/Trespasserr7
Soil
Surface Water*
1.4E-06
2.9E-02
NO
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
1.2E-05
2.8E-01
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Sort Gas to Indoor Air
6.4E-07
2.2E-02
NO
Indoor Air
0.0E+00
0.0E+00
NO
Soil and soil gas data collected from the footprint of proposed Building 2 were input to
the May 2019 Cumulative Risk Calculator. The Risk Calculator indicates that soil
contaminants do not pose an unacceptable risk to construction workers and/or future
workers and soil gas contaminants do not pose an unacceptable vapor intrusion risk to
future workers of Building 2.

Risk for Individual Pathways rel 1
Version Date: May 2019
Basis: May 2019 EPA RSL Table
Site ID: TW Alexander Flex Property
Exposure Unit ID: Building 3
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carc�skenic
Hazard Index
Risk exceeded?
Resident
Soil
9.3E_06
6.2E_02
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil
8.0E-07
4.5E-03
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Construction Worker
Soil
6.9E-07
4.5E-02
NO
Recreator/Trespasserr7
Soil
Surface Water*
5.2E-06
3.4E-02
NO
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
5.8E-06
1.2E-01
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Sort Gas to Indoor Air
4.0E-07
9.8E-03
NO
Indoor Air
0.0E+00
0.0E+00
NO
Soil and soil gas data collected from the footprint of proposed Building 3 were input to
the May 2019 Cumulative Risk Calculator. The Risk Calculator indicates that soil
contaminants do not pose an unacceptable risk to construction workers and/or future
workers and soil gas contaminants do not pose an unacceptable vapor intrusion risk to
future workers of Building 3.

Risk for Individual Pathways rel 1 W.
Version Date: May 2019
Basis: May 2019 EPA RSL Table
Site ID: TW Alexander Flex Property
Exposure Unit ID: Building 4
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carc�skenic
Hazard Index
Risk exceeded?
Resident
Soil
1.4E_06
3.1E-02
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil
3.1E-07
2.4E-03
NO
Groundwater Use*
0.0E+00
0.0E+00
NO
Construction Worker
Soil
5.1E-08
2.5E-02
NO
Recreator/Trespasserr7
Soil
Surface Water*
7.6E-07
1.7E-02
NO
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
1.7E-05
4.1E-01
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Sort Gas to Indoor Air
1.3E-06
3.3E-02
NO
Indoor Air
0.0E+00
0.0E+00
NO
Soil and soil gas data collected from the footprint of proposed Building 4 were input to
the May 2019 Cumulative Risk Calculator. The Risk Calculator indicates that soil
contaminants do not pose an unacceptable risk to construction workers and/or future
workers and soil gas contaminants do not pose an unacceptable vapor intrusion risk to
future workers of Building 4.
Required Land Use Restrictions:
The Brownfields Agreement for this property will include standard land use restrictions,
including prohibition on groundwater use, soil restrictions, EMP requirement, access,
notifications, and well abandonment with the exception of active groundwater monitoring
wells AD-50, M-4-50R, M-R-150R, M-4-200R, M-3-50, CW-4D, CW-41)ike, CW-4S,
CW-5D, CW-5S, CW-6D, and CW-6S, subject to the protection or abandonment and
replacement of groundwater monitoring wells as necessary for continued monitoring of
the Weck groundwater plume.
Based on the site -specific data provided to the Brownfield program, the site will be
suitable for the intended reuse as long as the agreed upon land use restrictions in the BFA
are abided by.