22059_GlaxoSmithKline_DM_06.10.2020

DECISION MEMORANDUM
DATE: June 9, 2020
FROM: Brad Atkinson
TO: Brownfields Assessment File
RE: G1axoSmithKline LLC
3029 E. Cornwallis Rd.
Durham, Durham County
Brownfields Project No. 22059-18-032
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than office, industrial, research laboratory,
parking, open space, recreational use, and with prior written approval from DEQ, other
commercial uses, can be made suitable for such uses.
Introduction:
The Prospective Developer is TKC — 3029 Holdings, LLC located at 4500 Cameron
Valley Parkway, Ste. 400, Charlotte, NC 28211.
The Brownfields Property is comprised of approximately 104 acres of previously
developed commercial property in Research Triangle Park, Durham County with PIN
157260. All previous structures have been razed and the property is not in use.
The Brownfields Property is regulated under the DWM Hazardous Waste Section with
permit number NCD052547635 and the DWM Underground Storage Tank Section with
incident numbers 14105, 26415 and 85976.
Redevelopment Plans:
The Prospective Developer desires to redevelop the Brownfields Property for non-
residential uses with eight proposed buildings. Site development plans call for two
phases of development. Phase I of the redevelopment consists of six buildings that are
currently planned for areas outside of the known contaminated areas of the Brownfields
Property and Phase II consists of two buildings that may be located over the Brownfields
Property's groundwater plumes.
The maximum total footprint of all buildings on the Brownfields Property is limited to
683,522 square feet based on the 104-acre site per Research Triangle Park Foundation
zoning restrictions. Square footage, location, and number of the individual buildings may
change from the current proposed design depending on the needs of the future building
occupants. All parking is planned as surface parking and no subgrade construction is
planned. VI mitigation is not warranted for the six Phase I buildings as proposed in their
current locations. VI mitigation will likely be necessary for the two proposed Phase II

buildings. Additional assessment in Phase II will be needed to evaluate the potential
risks associated with vapor intrusion and contaminated soils.
Site History:
From at least 1937 until 1957, the Brownfields Property was used for agricultural and
residential purposes. Between 1957 and 1959, the Brownfields Property was purchased
as a part of a block of property to become the Research Triangle Park. The Brownfields
Property was purchased in 1960 by the Chemstrand Research Center, Inc. (Chemstrand).
Chemstrand Research Center, Inc. was a wholly -owned subsidiary of the Chemstrand
Corporation, a joint venture between the Monsanto Company and the American Viscose
Corporation. Chemstrand developed the Brownfields Property for textiles research,
development, and manufacturing from the 1960s until the early 1980s. During that time,
Monsanto became the full owner of the Brownfields property via the purchase of
American Viscose's interest in the joint venture.
On February 17, 1984, Monsanto sold the Brownfields Property to the Burroughs
Wellcome Company at which time it was used for pharmaceutical research and
development. Pharmaceutical research and development operations continued through
different entities as a result of multiple mergers and acquisitions. These entities included
Glaxo Wellcome, and ultimately G1axoSmithKline (GSK). At the time of the original
development and over the duration of the Monsanto and Burroughs Wellcome ownership,
the Brownfields Property improvements consisted of approximately 78,990 square feet of
office/laboratory manufacturing space, two warehouses, three waste storage pads, an
incinerator building, tennis courts, a wastewater aeration basin, and a wastewater pond
that was later backfilled and used for recreational fields.
In 2011-2012, GSK decommissioned the facility and demolished all the vertical
improvements down to the foundations except for one warehouse building (Warehouse
B), a water pump station building, the tennis courts and the concrete/asphalt parking and
driveway areas.
On December 13, 2018, the Prospective Developer purchased the Brownfields Property
from GSK. The Warehouse B building, tennis courts, and the remaining portion of a
concrete slab associated with former Warehouse A were demolished by the Prospective
Developer in early April 2020.
All remediation activities referenced below were conducted by GSK under its Resource
Conservation and Recovery Act [RCRA] Permit NCD 052547635. Since the mid- 1980s,
environmental investigations and site remediation were completed with oversight by the
NC Hazardous Waste Section and the US Environmental Protection Agency (EPA). The
EPA oversight is limited to the assessment and remediation of releases of polychlorinated
biphenyls (PCBs) under Toxic Substances Control Act (TSCA) regulation. Since 1996,
environmental investigations and site remediation have been completed as part of
corrective action activities under GSK's RCRA Permit NCD 052547635. On February
26, 2019, the Prospective Developer was approved to be listed as owner of the facility on
the GSK RCRA Permit NCD 052547635 for the facility. The approval was made by way
2

of a Class 1 permit modification under 40 CFR 270.42 as adopted in 15A NCAC 13A
.0113, which was approved by the NC Hazardous Waste Section and issued to GSK. The
approval letter also acknowledged that GSK shall, for purposes and requirements of the
RCRA permit, remain the legal operator of the facility and will retain sole responsibility
for RCRA compliance, including operation of corrective action activities and
maintenance of financial assurance. Any pending or completed brownfields agreement
does not and will not change this GSK operator designation or their permit liabilities and
obligations.
RCRA corrective action activities completed at the Brownfields Property have identified
multiple Solid Waste Management Units (SWMUs) and Areas of Concern (ADCs). In
general, the SWMUs represent areas where waste storage, waste landfilling, waste
treatment, wastewater treatment and discharge, and chemical storage activities were
performed. AOCs are areas where elevated levels of constituents were detected in the
soil or groundwater that were not released as a result of a process and where a local
source was not identified, unlike the identification of the SWMUs.
Summaries of the SWMUs and AOCs where releases were identified are as follows:
SWMU 4: SWMU 4 is located in the eastern portion of the Brownfields Property and is
a former concrete wastewater aeration basin previously used as a biological and chemical
treatment unit for laboratory wastewater from 1960 until 1966, when the basin was taken
out of operation and no longer used. Prior to being taken out of service, the treated
wastewater was discharged to an adjacent surface impoundment (SWMU 12) for further
aeration and biological treatment. Once use of the basin was discontinued, wastewater
was discharged to the Durham County public sewer system. The former wastewater
aeration basin in SWMU 4 was excavated and removed in 1988.
Soil excavation activities were completed at SWMU 4 (along with AOC Fermentation
Building and AOC Stormwater Channel) in 2004 and 2005 to remove soil impacted with
VOCs, SVOCs, and PCBs. As part of excavation activities, approximately 2,280 tons of
excavated soil were exported for disposal at Republic Services, Inc.'s Upper Piedmont
Landfill in Rougemont, North Carolina, and 66 tons of PCB -impacted soil (PCB
detections above 50 milligrams per kilogram [mg/kg]) were exported for disposal at
Chemical Waste Management, Inc.'s Emelle, Alabama facility. EPA approved the PCB
remedy on December 1, 2011. NC Hazardous Waste Section issued a No Further Action
(NFA) letter for SWMU 4 for the soil contamination on April 22, 2016 and a NFA letter
for the localized groundwater impact on November 12, 2019.
SWMU 12: SWMU 12 is located in the eastern portion of the Brownfields Property and
is a former surface impoundment that received treated wastewater from SWMU 4. In
1984, the former surface impoundment was drained and backfilled with soil from a local
rock quarry in Morrisville, North Carolina, and was subsequently used as recreational
fields. The 2004 soil excavation activities completed at SWMU 4 included the drainage
ditch from SWMU 4 to SWMU 12 to remove PCBs at concentrations above the
residential Primary Remediation Goal established by EPA of 0.22 mg/kg.

Additional soil sampling was conducted at SWMU 12 in 2012 which indicated that
remaining soil met the TSCA High Occupancy Area cleanup level for PCBs of less than
or equal to 10 mg/kg for areas with an appropriate soil cover. The existing 18-inch soil
cover was approved as the remedy by EPA on April 29, 2013; it must be maintained as
part of EPA requirements under land use restrictions recorded with the property deed at
the Durham County Register of Deeds Office on November 6, 2014 in Book 7597, Pages
858 — 861. The NC Hazardous Waste Section issued a NFA Letter for VOCs in soils on
April 22, 2016.
SWMU 13: SWMU 13 is located in the northern portion of the Brownfields Property and
is a former landfill area where chemical wastes were placed in a series of unlined
trenches from approximately 1960 to 1972. In the mid- 1980s, five of the trenches were
excavated to bedrock (approximately 15 feet below ground surface [bgs]), backfilled with
soil, and covered with a clay cap. In addition to use as a former landfill, this area was
also used as a former fire training pit where fuels were burned for employee fire
suppression training. In 2013 through 2014, soil excavation activities were completed at
SWMU 13 to remove PCBs in soils at concentrations above the TSCA High Occupancy
Area Standard (HOS) of 1 mg/kg in accessible areas including outside the fenced area,
and in shallow soils in the vicinity of the fire training pit.
Results of post -excavation sampling in SWMU 13 indicated that remaining soil had
successfully been remediated to the TSCA HOS cleanup level for PCBs of less than or
equal to 10 mg/kg for areas with an appropriate soil cover. The existing 24-inch soil
cover was approved by EPA as the remedy and must be maintained as part of EPA
requirements under land use restrictions recorded with the property deed at the Durham
County Register of Deeds Office on November 6, 2014 in Book 7597, Pages 858 — 861.
Remediation of VOCs in soil or weathered rock and groundwater at SWMU 13 is
currently being conducted by soil vapor extraction and insitu treatment of groundwater by
injection of zero-valent iron (ZVI) into the aquifer (DEQ Injection Permit WI 0501044),
respectively, as part of RCRA correction action activities.
SWMU 15: SWMU 15 is located in the central portion of the Brownfields Property and
is a former bum/gravel pit that was used for waste disposal from approximately 1960
through 1970. In addition, two former 30,000-gallon fuel oil underground storage tanks
(USTs) were located in this area. Historical assessment activities conducted at SWMU
15 identified the presence of PCBs in soil and VOCs in soil and groundwater above
regulatory screening criteria. In 2003, the fuel oil USTs were closed in -place by
removing residual petroleum sludge followed by placement of foam and concrete in the
USTs. A fuel oil return line associated with the closed -in -place USTs was also removed
during corrective action activities. The UST fill port structures, vent pipes, and metal
pump pit were then removed and disposed of off -site. Post -UST closure soil sampling
results did not indicate exceedances of DEQ UST Section Maximum Soil Contaminant
Concentrations (MSCCs).
2

A Notice of No Further Action (NFA) was granted for the petroleum release (UST
Section Incident No. 26415) on March 5, 2015. Approval for a self -implementing
remedy for PCB contaminated soil under TSCA regulation was issued by EPA in a letter
dated August 8, 2013. In 2013 through 2014, soil excavation activities were completed at
SWMU 15 to remove PCBs at concentrations above the HOS and VOCs above the
applicable DWM PSRGs and site -specific soil concentrations based on Synthetic
Precipitation Leaching Procedure (SPLP) testing.
Excavations completed for SWMU-15 were terminated at bedrock and additional impacts
may potentially exist at the base of those excavations and/or in bedrock below the
excavations. To address these impacts, zero valent iron (ZVI) was placed at the base of
the excavation at a thickness of approximately one foot to aid in the remediation of VOCs
in underlying weathered bedrock and groundwater. The ZVI was mixed with sand
followed by approximately two 2-foot lifts of 3- to 4-inch ballast stone.
In a letter dated April 22, 2016 from the NC Hazardous Waste Section, SWMU 15
received NFA status for VOCs in soil. Remediation of VOCs in groundwater at SWMU
15 is currently being conducted by the injection of ZVI into the aquifer (DEQ Injection
Permit WI 0501044) as part of RCRA correction action activities.
SWMU 16: SWMU 16 is located in the west -central portion of the Brownfields Property
in the vicinity of a former waste storage area where management of hazardous substances
occurred. Historical assessment activities conducted at SWMU 16 identified the presence
of PCBs in soil and VOCs in soil and groundwater above regulatory screening criteria.
Approval for a self -implementing remedy for PCB contaminated soil under TSCA was
issued by EPA on August 8, 2013. In 2013 through 2014, soil excavation activities were
completed at SWMU 16 to remove PCBs at concentrations above the HOS and VOCs
above their respective PSRGs and site -specific soil concentrations based on SPLP testing.
Excavations completed for SWMU-16 were terminated at bedrock. Because additional
impacts could potentially exist at the base of those excavations and/or in bedrock below
the excavations, ZVI was placed at the base of the excavation at a thickness of
approximately one foot to aid in the remediation of VOCs in underlying weathered
bedrock and groundwater. The ZVI was mixed with sand followed by approximately two
2-foot lifts of 3- to 4-inch ballast stone.
In a letter dated April 22, 2016 from the NC Hazardous Waste Section, SWMU 16
received NFA status for VOCs in soil. Remediation of VOCs in groundwater at SWMU
16 is currently being conducted by the injection of ZVI into the aquifer as part of RCRA
correction action activities.
AOC GW-6, and AOC W-1: The AOCs named AOC GW-6 and AOC W-1 are located
in the southwestern and western portions, respectively, of the Brownfields Property in
areas not known to have been associated with any manufacturing or waste management
activities. However, assessment activities conducted in the vicinity of these AOCs
indicated the presence of VOCs in groundwater above regulatory screening criteria. GSK
5

has extended AOC GW-6 groundwater monitoring and remediation efforts upgradient
along geologic strike, and refers to this area as Area Along Strike of AOC GW-6, which
is located in the central to southwestern portion of the Brownfields Property.
AOC Fermentation Building: AOC Fermentation Building is located in the western
portion of the Brownfields Property. During Monsanto operations, wastewater
discharges that included some PCB content were mistakenly drained to a stormwater
discharge. Soil excavation activities were completed at AOC Fermentation Building
(along with SWMU-4 and AOC Stormwater Channel) in 2004 and 2005 to remove PCBs
to below 0.22 mg/kg, the Residential Primary Remediation Goal established by EPA. No
contaminants other than PCBs were detected in the soil at AOC Fermentation Building.
Approximately 709.52 tons of excavated soil were disposed of off -site at Republic
Services, Inc.'s Upper Piedmont Landfill in Rougemont, North Carolina. Following
excavation, the area was backfilled with clean fill. Under TSCA regulation, EPA
approved the self -implementing remedy on August 8, 2013.
AOC North Parking Lot: AOC North Parking Lot is located in the central portion of the
Brownfields Property. PCB -impacted soil was identified during a site improvement
project in 2002. Soil excavation activities were subsequently completed in 2002, 2003,
2013, and 2014 to remove PCBs. Approval for a self -implementing remedy for PCB
contaminated soil under TSCA regulation was issued by EPA in a letter dated August 8,
2013.
AOC Stormwater Channel: AOC Stormwater Channel is located in the northwestern
portion of the Brownfields Property and is a former drainage channel not known to have
been associated with any waste management activities. However, assessment activities
conducted in the vicinity of AOC Stormwater Channel indicated the presence of PCBs in
soil. Soil excavation activities were subsequently completed at AOC Stormwater Channel
(along with SWMU-4 and AOC Fermentation Building) in 2004 and 2005 to remove
PCBs to below 0.22 mg/kg, the Residential Primary Remediation Goal established by
EPA. Approximately 3,247.84 tons of excavated soil were disposed of off -site at
Republic Services, Inc.'s Upper Piedmont Landfill in Rougemont, North Carolina.
Following excavation, the area was backfilled with clean fill. This remedy was approved
by EPA in a letter dated December 1, 2011.
Potential Receptors:
Potential receptors are: construction workers, on -site workers, future workers, visitors,
and trespassers.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property:
Groundwater, soil 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
2

Soil contamination was assessed and remediated under the RCRA permit which has been
and will continue to be overseen by both the NC Hazardous Waste Section and the EPA.
The Hazardous Waste Section retained oversight responsibility for VOC contaminated
soil. EPA retained oversight responsibility for PCB contaminated soil with clean-up
standards based on the Toxic Substance Clean-up Act standards of 40 CFR § 761.61.
Historical soil assessment activities conducted at the Brownfields property have
identified the presence of polychlorinated biphenyls (PCBs), volatile organic compounds
(VOCs), and/or semi-VOCs (SVOCs) in the SWMUs and AOCs. PCBs were also
identified in areas outside of the SWMUs and AOCs as a potential result of termite and
dust management practices performed historically in the northern portion of the
Brownfields property. Specifically, PCBs detected during historical soil assessment
activities have included Aroclors 1232, 1242, 1248, 1254, and 1260. GSK environmental
personnel maintain that, to the best of their knowledge, all VOCs present in soil at the
Brownfields Property have previously been excavated and disposed of off -site, except
those VOCs at depth in soil or weathered rock remaining in the RCRA permit designated
area known as SWMU 12 & SWMU 13.
Summaries of the soil contamination related to SWMU and ADCs are as follows:
SWMU 4: In 2004 and 2005, all soil impacted with VOCs, SVOCs, or PCBs above their
respective clean-up levels has been excavated, removed off -site, and disposed of in a
licensed disposal facility.
SWMU 12: PCBs remain in soil at depths ranging from 2 — 9 feet bgs at concentrations
equal to or less than 10 mg/kg, which is allowable under TSCA regulations. No VOCs in
soil are believed to remain above the DWM non-residential Preliminary Soil Remedial
Goals (PSRGs) in this area.
SWMU 13: Results of post -excavation sampling in SWMU 13 indicated that remaining
soil had successfully been remediated to the TSCA High Occupancy Area cleanup level
for PCBs of less than or equal to 10 mg/kg for areas with an appropriate soil cover. Soil
contaminants remaining are PCBs (<10 mg/kg), TCE (5.8J mg/kg), and chloroform (3.4J
mg/kg) at depths ranging from 2 — 14 feet bgs at various locations in this area.
SWMU 15: Post -UST closure soil sampling results did not indicate exceedances of DEQ
UST Section Maximum Soil Contaminant Concentrations (MSCCs). In 2013 through
2014, soil excavation activities were completed at SWMU 15 to remove PCBs at
concentrations above the HOS, VOCs above the PSRGs, and site -specific soil
concentrations based on Synthetic Precipitation Leaching Procedure (SPLP) testing.
SWMU 16: In 2013 through 2014, soil excavation activities were completed at SWMU
16 to remove PCBs at concentrations above the HOS, VOCs above their respective
PSRGs, and site -specific soil concentrations based on SPLP testing.
7

AOC GW-6, and AOC W-1: No soil contaminants are known to exist above their
respective PSRGs in these areas nor in the Area Along Strike of AOC GW-6.
AOC Fermentation Building: No contaminants other than PCBs were detected in the soil
at AOC Fermentation Building, and the impacted soil was previously excavated to below
0.22 mg/kg, the Residential Primary Remediation Goal established by EPA.
AOC North Parking Lot: PCB -impacted soil was identified during a site improvement
project in 2002, but soil excavation activities completed in 2002, 2003, 2013, and 2014
removed PCBs to below 1 mg/kg, the High Occupancy Standard established by EPA.
AOC Stormwater Channel: PCB -impacted soil was identified, but soil excavation
activities in 2004 and 2005 removed PCBs to below 0.22 mg/kg, the Residential Primary
Remediation Goal established by EPA.
Groundwater
Groundwater monitoring has occurred for multiple decades in upwards of 100 monitoring
wells over that time period. Historical groundwater assessment activities conducted at the
Brownfields Property have identified the presence of VOCs in groundwater at
concentrations above the DEQ 15A North Carolina Administrative Code (NCAC)
02L .0202 Groundwater Quality Standards (2L Standards). VOCs detected in
groundwater above 2L Standards include primarily trichloroethylene (TCE),
tetrachloroethylene (PCE), and associated degradation compounds cis-1,2-dichloroethene
(cis-1,2-DCE) and vinyl chloride. Additionally, non -chlorinated VOCs, such as benzene,
have been detected at concentrations above their respective 2L Standards in groundwater.
Groundwater assessment and monitoring has occurred under the oversight of the NC
Hazardous Waste Section for multiple decades. A portion of the groundwater plume has
flowed offsite to the north; however, GSK maintains responsibility for addressing any
off -site risks from this segment of the plume.
Summaries of groundwater impacts at SWMUs and AOCs are as follows:
SWMU 4: PCE and benzene were detected in groundwater at GW-53S on 9/24/2012 at
0.97 micrograms per liter (µg/L) and 15 µg/L, respectively, and on 4/3/2019, those same
compounds were detected at <0.39 µg/L and 2.9 µg/L, respectively, indicating a decline
of these compounds in this well over that time period.
SWMU 12: No groundwater contaminants above the 2L standards are known to exist in
this area.
SWMU 13: Remediation of VOCs in groundwater at SWMU 13 is currently being
conducted by soil vapor extraction and insitu treatment of groundwater by injection of
zero-valent iron (ZVI) into the aquifer (DEQ Injection Permit WI 0501044) as part of
RCRA correction action activities. TCE and 1,2-dichloroethane were detected in

groundwater in this area up to the maximum concentrations of 150,000 µg/L and 29,000
µg/L, respectively in wells BNP-1/IW-17 on 04/08/2008. However, the most recent
concentrations for those compounds in these same wells were <150 µg/L and 390 µg/L,
respectively.
SWMU 15 & SWMU 16: TCE was detected in groundwater at GW-41 S, a well
associated with both SWMU 15 and SWMU 16, at 4,300 µg/L on 3/20/2008 and at 33
µg/L on 4/2/2019, indicating about a two order of magnitude reduction in concentration
of TCE in this well over that time period.
AOC GW-6 and AOC W-1: At AOC GW-6, TCE and Tetrachloroethene (PCE) were
detected in groundwater at 55 µg/L and 7.6 µg/L on 3/18/2008, and at <0.74 µg/L on
4/2/2019 and 0.39 µg/L on 4/1/2019, respectively. At AOC W-1, TCE and PCE were
detected in groundwater at 200 µg/L and 7.4 µg/L respectively on 4/10/2014 and 3/14/20,
and at <74 µg/L and <39 µg/L on 4/3/2019 respectively.
AOC Fermentation Building: No groundwater contaminants are known to exist above
applicable 2L standards in this area.
AOC North Parking Lot: No groundwater contaminants are known to exist above the
applicable 2L standards in this area.
AOC Stormwater Channel: No groundwater contaminants are known to exist above the
applicable 2L standards in this area.
Surface Water
Surface water is not located on the site.
Soil Vapor
Twenty exterior soil gas samples were collected from within the planned footprints of the
six proposed Phase I buildings of the redevelopment. Soil vapor monitoring points were
installed from 6 to 11.5 feet bgs. No soil vapor samples were collected in the Phase II
redevelopment area.
No soil gas analytes were detected above their respective non-residential soil -gas
screening levels. TCE was detected at a concentration of 86 µg/m3 and 20 µg/m3 at
SVMP-6 and SVMP-5, respectively. All other detections of TCE ranged from below
reporting limits up to the estimated value of 7.1J µg/m3. Benzene was detected at 95
µg/L, 86 µg/m3 and 74 µg/m3 at SVMP-2, SVMP-17 and SVMP-15, respectively.
Benzene was detected at concentrations ranging from LOJ µg/m3 to 62 µg/m3 in each of
the other of the soil gas samples.
Sub -Slab Vapor
No structures are present on the Brownfields Property. Therefore, no sub -slab samples
were collected.
0

Indoor Air
No structures are present on the Brownfields Property. Therefore, no indoor air samples
were collected.
Risk Calculations
Risk calculations were performed using the most recent DEQ Risk Calculator
https:Hdeq.nc. gov/permits-rules/risk-based-remediation/risk-evaluation-resources.
For the purposes of looking at the site spatially, risk calculators were run for the footprint
of each proposed building as reflected on the map at the end of this document. Due to the
vast amount of groundwater data collected over multiple decades from upwards of 100
monitoring wells, groundwater data used for the risk calculators was limited to data found
in Exhibit 2. Soil gas data used for the risk calculations was from recent soil gas
assessment work conducted on behalf of the Prospective Developer. Soil data that
exceeds PSRGs exists only for SWMU 12 and SWMU 13 because all other soil with
known exceedances of the PSRGs is believed to have been excavated and removed from
the Brownfields Property during remediation overseen by the NC Hazardous Waste
Section and the EPA.
Phase I buildings: Risk calculators were performed for the footprints of Buildings 1 — 6
planned for Phase I. Only soil gas data was used in the risk calculation because no soil or
groundwater contaminants beneath the footprints of the Phase I buildings was present in
Exhibit 2.
Phase II buildings: Risk calculators were performed for the footprints of Buildings 7 and
8 planned for Phase II. Only groundwater data was used in the risk calculation because
no soil gas data yet exists and no soil contaminants beneath the footprints of the Phase II
buildings was present in Exhibit 2. Groundwater data used for Building 7 are from
SWMU 15/16 from Exhibit 2. Groundwater data used for Building 8 are from Area
Along Strike of AOC GW-6 from Exhibit 2.
Construction over SWMU 12 and 13 has been deed -restricted by RCRA; therefore, no
risk calculations were run by Brownfields for those areas with known soil and
groundwater contaminants.
The risk calculations indicated the following based on available data, including the
following media: groundwater and soil gas, with the limitations as described above.
The risk calculation results for each of the six buildings in Phase I (Buildings 1-6)
indicate that based on the range of a low of 1.2E-02 (0.012) to a maximum noncancer risk
hazard index for soil gas to indoor air of 9.2E-02 (0.092), no vapor mitigation is
warranted for any of the six Phase I buildings given their current proposed footprint. The
acceptable environmental risk range of carcinogenic risk of up to 1E-04 is not exceeded
for any of the six buildings.
10

The risk calculation results for the remaining two buildings to be constructed during the
Phase II redevelopment (Buildings 7 and 8) indicate that based on the range of a low of
1.9E-01 (0.19) for Building 7 to a maximum noncancer risk hazard index for
groundwater to indoor air of 8.2E-01 (0.82) in Building 8, a concern exists that potential
vapors could accumulate beneath the slab of a future building and potentially create a
vapor intrusion problem. Therefore, prior to building construction in this area, additional
assessment of soil gas, potentially followed by sub -slab soil vapor and/or indoor air, is
warranted. Based on the results, a passive or active vapor intrusion mitigation system
may or may not be required in these two buildings.
The acceptable environmental risk range of carcinogenic risk of up to 1E-04 is not
exceeded for any of the two Phase II proposed buildings.
Risk calculations indicate that based on a noncancer risk hazard index of 1.4 for
nonresidential groundwater use scenarios for Building 8, which exceeds the regulatory
threshold of a hazard index of 1, that groundwater use must be restricted.
Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-032
Ex sure Unit ID: Buildin 1 - Phase I
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
Carcinogenic
Hazard Index
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
1.2E-06
5.0E-02
NO
Indoor Air
NC
NC
NC
11

Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-059
Exposure Unit ID: Building 2 -Phase I
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Iiazardlndex
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 _ �7 ________
Surface Water*
NC
NC
NC
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
llazardlndex
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
1.8E-06
9.2E-02
NO
Indoor Air
NC
NC
NC
Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-059
Exposure Unit ID: Building 3 -Phase I
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carci nogenic
Risk
llazardlndex
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
Carcinogenic
Risk
llazardlndex
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
Sort Gas to Indoor Air
4.5E-06
5.11-02
NO
Indoor Air
NC
NC
NC
12

Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-032
Ex sureUnit ID: Buildin 4 - Phase I
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
Surface Water*
NC
NC
NC
-
NC
tm --- NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardhidex
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
4.0E-07
1.2E-02
NO
Indoor Air
NC
NC
NC
Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-032
Exposure Unit ID: Building 5 - Phase I
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
Carciinnogenic
sk
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
1.4E-06
5.0E-02
NO
Indoor Air
NC
NC
NC
13

Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-032
Exposure Unit ID: Building 6-Phase I
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Iiazardlndex
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 _ �7 ________
Surface Water*
NC
NC
NC
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
llazardlndex
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
1.3E-06
5.9E-02
NO
Indoor Air
NC
NC
NC
Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-032
Exposure Unit ID: Building 7-Phase II
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carci nogenic
Risk
llazardlndex
Risk exceeded?
Resident
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
NC
NC
NC
--------------
Groundwater Use*
8.1E-05
3.5E-01
NO
Construction Worker
Soil
NC
NC
NC
Recreator/Trespasser
Soil
NC
NC
NC
-------
Surface Water*
NC
NC
-----
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
llazardlndex
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
1.4E-05
1.9E-01
NO
Sort Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
14

Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22059-18-032
Exposure Unit ID: Building 8 - Phase II
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
CarcinogenicRisk
I3azardlndex
Risk exceeded?
Resident
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
NC
NC
NC
Groundwater Use*
7.8E-05
1.4E+00
YES
Construction Worker
Soil
NC
NC
NC
Recreator/Trespasser
Soil _ r7 ________
Surface Water*
NC
NC
NC
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
CarcinogenicHazardlndex
Risk
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
1.5E-05
8.2E-01
NO
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
Required Land Use Restrictions:
Land use restrictions (LURs) will include those related to the following: anticipated land
uses and their definitions, daycares, requirement for an Environmental Management Plan
and redevelopment report, groundwater use, soil disturbance, final grade sampling, access
for environmental work, vapor mitigation, maintaining soil cover and vegetative growth
on existing soil caps part of EPA and RCRA remedial efforts, prohibition on the
movement of PCB impacted soil without DEQ approval, prohibition on use of products
with known contaminants unless above ground piping over solid surfaces with secondary
containment and a site -specific spill control plan are employed, and LUR update
obligation.
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.
Property Management Unit considerations:
Unless pre-emptive vapor mitigation is employed for the buildings proposed in Phase II,
additional soil gas assessment will be warranted for the proposed buildings in that later
phase.
Off -site contamination is managed by G1axoSmithKline with oversight from the RCRA
Program.
15

Former Monsanto/G1axoSmithKline facility with Proposed buildings in yellow and Phase
I / Phase II boundary in fuchsia.
16