20010_Sonrise Industrial_Dec Memo_20231024

DECISION MEMORANDUM
DATE: October 24, 2023
FROM: Stephanie Graham
TO: BF Assessment File
RE: Sonrise Industrial Center
1200 Henry Street
Roanoke Rapids, Halifax County
BF # 20010-16-042
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than warehousing, distribution, food
processing, indoor aquaculture, industrial, retail, office, data center, 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 Halifax County Business Horizons, Inc, a private non-
profit corporation, located at 260 Premier Boulevard, Roanoke Rapids, NC 27870. Cathy
Scott is the contact for the PD, and Daniel Brown is the President of the corporation. The
PD has been in discussions with a confidential private party about purchasing the
Brownfields Property, and the sale is projected to close by November 30, 2023.
The Brownfields Property consists of 55.878 acres, which includes Monroe Street, and
includes four buildings, vacant land and surface parking. The parcel identification
numbers and tracts associated with the property include Tract 1: portion of 0911564,
0900566 and 0920096 (47.13 acres including Monroe Street); Tract 2: portion of
0911564 (1.24 acres); Tract 3: 0900551 (0.868 acres); Tract 4: 0900556 (1.64 acres); and
Tract 5: 0911457 (5.00 acres).
The Brownfields Property consists of a vacant industrial property previously occupied by
textile manufacturers. Some of the buildings and infrastructure at the Brownfields
Property have been salvaged by the current property owner, Sonrise Reclamation, LLC.
Redevelopment Plans:
To date, no site -specific drawings for the planned redevelopment have been provided by
the PD, but conceptually, we understand that the existing buildings at the Brownfields
Property will be retrofitted for the uses listed above. Based on the limited nature of vapor
intrusion data, vapor assessment and potentially mitigation steps may be necessary based
on the findings of pre -occupancy, and if necessary, post -occupancy sampling after the
existing buildings are retrofit and have operational HVAC systems.
Sonrise Industrial Center/20010-16-042/240et2023

Site History:
Previous uses of the Brownfields Property include textile mill operations from
approximately 1900 until 2003. A total of 15 buildings and two concrete -lined ponds
were present in 1994. The two ponds are located on the southern portion of the property
and were previously used as a water source for firefighting activities (small pond) and
wastewater pre-treatment (larger pond). The most recent textile facility (West Point
Stevens Rosemary Complex) operated from 1996 to 2003 and included the use of three
textile mill buildings, a finishing plant, two warehouses and a company store building.
Demolition activities of several buildings were conducted by Sonrise Reclamation, LLC
between 2005 and approximately 2014.
Seven underground storage tanks (USTs) were previously located onsite and related to
the former textile mill operations. Additional information is provided below.
• In 1991, a 100-gallon gasoline or diesel UST identified as Tank 1 was removed
from the fire pump building located near the reservoir on the southern portion of
the property. No contaminants of concern (COCs) were detected during soil
sampling, and the UST was replaced with either a 550 or 100-gallon tank, which
was subsequently removed in 2009. No closure documents were available for the
2009 UST closure activities, but in 2018 and under approval from the UST Trust
Fund Branch, one soil and one groundwater sample were collected in the area of
this removed UST. No COCs were identified in the soil sample, so the
groundwater sample was not analyzed. A No Further Action letter was issued
related to the 2018 sampling, and the removal of this UST is associated with
onsite UST Incident Number 10220 (Bibb Company Rosemary Plant).
• In 1991/1992, three USTs were removed, and petroleum soil contamination was
identified. These USTs included a 1,000-gallon gasoline UST (Tank 2), and two
550-gallon gasoline or diesel (Tank 3) and varsol (Tank 4) USTs. The
contaminated soil appears to have been excavated and land applied under DEQ
(previously DENR) approval in 1992 at an offsite location (900 Jefferson Street).
In 1997 and based on information provided by previous property owners,
additional soil excavation and sampling were conducted in the former UST pit
area, and reportedly, no COCs were detected in the soil samples collected. No
closure documentation was available for these three USTs; however, during the
2021 Brownfields assessment, a monitoring well (MW-4) was located in a relative
downgradient location of the former UST pit.
• In 1993, two additional USTs were removed from the Rosemary Plant
(Brownfields Property), and soil sampling identified petroleum COCs. Of note,
the removal of these two USTs are documented in a report associated with
Roanoke #2 Plant, which was the location of a second facility located
approximately 0.5 miles north of the Brownfields Property. The two plants were
owned and operated by the same entity (Bibb Company).
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Sonrise Industrial Center/20010-16-042/240et2023

Site assessment at the Brownfields Property in 2021 and 2022 identified impacts from
various petroleum and chlorinated solvent compounds above applicable regulatory
standards or screening levels.
Potential Receptors:
Potential onsite receptors include construction workers, onsite workers, and trespassers.
Based on the elevated concentrations of chlorinated solvents in well MW-15 on the south
(downgradient) side of the plant building, the Brownfields Redevelopment Section
consulted with the DWM Inactive Hazardous Sites Branch (IHSB) regarding the potential
for offsite migration of contaminants. In 2022, IHSB requested that the USEPA assess
this area. EPA, in consultation with the PD, conducted assessment work along the
southern property boundary and offsite to determine if offsite impacts existed related to
the known chlorinated solvent groundwater contamination found at the Brownfields
Property. EPA's assessment results confirmed the presence of elevated concentrations of
chlorinated solvents in well MW-15, noted the presence of chlorinated solvents in one
offsite surface water body, but did not detect site COCs in the shallow soil vapor along
the southern property boundary.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
groundwater, sub -slab vapor, indoor air, surface water, and sediment. 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 COCs.
Soil
Soil data from the Brownfields Property was collected in 2016 and 2021 to a depth of 20
to 25 feet (B-1) below ground surface (bgs), and arsenic was detected above its DEQ
Preliminary Soil Remedial Goal (PSRG) for industrial land use. Additional compounds
detected in soil included acenaphthylene, benzo(g,h,i)perylene and phenanthrene, but
there are no established PSRGs for these compounds. The residential land use risk is
exceeded; however, the intended reuse of the site is for non-residential only.
Groundwater
Onsite groundwater samples were collected in 2016, 2021 and 2022, and various volatile
organic compounds (VOCs), including trichloroethene (TCE) and tetrachloroethene
(PCE), were detected above their respective NC 2L groundwater standards. In addition,
1,2,3-trichlorobenzene was detected in onsite groundwater; however, a groundwater
standard has not been established for this compound. These COCs are associated with the
previous onsite operations. Various chlorinated solvents detected during the groundwater
sampling at the Brownfields Property exceed their respective Non -Residential Vapor
Intrusion Screening Levels (VISLs) for VOCs in groundwater. The TCE and PCE
concentrations were lower between the 2021 and 2022 sampling events, with PCE
concentrations in well MW-15 less than one-half the concentration in 2022 compared
Sonrise Industrial Center/20010-16-042/240et2023

with 2021, and with a decrease in an order of magnitude in the concentration of TCE in
well MW-15 from 2021 to 2022.
In EPA's investigation, they collected groundwater samples from several wells on the
downgradient side of the site (MW-3, MW-14, MW-15 and MW-16), and collected a
groundwater sample at the southern property boundary (TW-01) from a temporary well.
Sub -Slab Vapor
Ten sub -slab vapor samples, including one duplicate, were collected on the Brownfields
Property in 2021 and 2022. Sample SG-2 and its duplicate (SG-DUP), located in the
Fabricating Plant Annex, were collected below a wooden floor present in the area of
these samples; however, a slab was not confirmed to be present. The sub -slab samples
were collected from installed Vapor Pins. Ethylbenzene, naphthalene and total xylenes
exceeded their respective non-residential VISLs for soil vapor. Other compounds
detected in these sub -slab vapor samples include acetone, 1,3-dichlorobenzene, 4-
ethyltoluene and trichlorofluoromethane, but there are no established VISLs for these
compounds.
Exterior Soil Gas
During the 2022 EPA investigation, 31 passive exterior soil gas samples (Beacon
samplers), including two duplicates, were collected principally at the perimeter of the
Brownfields Property, with three onsite locations and three offsite locations. The
samplers were installed to detect shallow soil vapor at less than I -foot bgs and generally
concentrated along the south/southeastern property boundary. Three of the samples were
collected in the area of the former maintenance shop on the Brownfields Property. Three
additional samplers were placed at an offsite location, south of the Brownfields Property.
The analyte list was limited to benzene, toluene, ethylbenzene, total xylenes, PCE, TCE,
and their degradation products. While there were some detections of these compounds in
shallow soil vapor at the property boundary, none of these COCs were present at
concentrations above their respective non-residential VISL.
Crawlspace and Indoor Air
Given the size of the existing onsite buildings, there is very limited crawlspace and
indoor air data. That is principally because of the deteriorated condition of the buildings.
One crawlspace sample was collected from the office area of the Mill I building in 2021,
and one indoor air sample and its duplicate were collected in the former maintenance
shop in 2022. The crawlspace air sample is considered to be equivalent to indoor air for
regulatory purposes. Chloroform and naphthalene exceeded their respective non-
residential VISLs for indoor air. Other compounds detected in these samples include
acetone, cis-1,2-dichloroethylene and trichlorofluoromethane, but there are no established
VISLs for these compounds.
Additional indoor air, and potentially sub -slab vapor, data should be obtained after
existing buildings are retrofit and HVAC systems are operational pre -occupancy, and
potentially post -occupancy, to confirm the initial findings of the risk calculator output
with respect to the need for vapor intrusion mitigation measures.
4
Sonrise Industrial Center/20010-16-042/240et2023

Surface Water
In 2021, a surface water sample and its duplicate were collected from the former
wastewater reservoir located on the southern portion of the site. The estimated mercury
concentration exceeded the NC surface water target value for Class C waters. In addition,
cadmium and lead compounds were detected in the samples; however, the associated
standard could not be calculated, as the environmental consultant did not obtain hardness
data from the samples.
Sediment
In 2021, a sediment sample and its duplicate were also collected from the former
wastewater reservoir located on the southern portion of the site. Arsenic exceeded its
PSRG for industrial land use. Phenanthrene was also present in the sample, but a PSRG
has not been established for this compound.
Risk Calculations
Risk calculations were performed using the July 2022 DEQ Risk Calculator
https:Hdeq.nc. goy/permits-rules/risk-based-remediation/risk-evaluation-resources.
The risk calculator was most recently updated in July 2023; however, we evaluated the
contaminant list that changed for the most recent risk calculator but found that those
contaminants did not apply to this particular Brownfields Property. Therefore, the risk
calculator output from the July 2022 risk calculator is still considered valid for the data
set at this site. For the purposes of looking at the site spatially, the site was divided into
six areas consisting of Mill 1 and Northern Area; Mill 2 and Eastern Area; Mill 3, Mill 5,
Slasher Building and Delta 4 Finishing Plant; Fabricating Plant, Fabricating Plant Annex,
Distribution Warehouse and Maintenance Shop; Southern Reservoir; and Southern
Property Boundary. The sub -slab vapor samples were collected through vapor pins into
1-L Summa canisters from below existing slabs, although in some samples, the buildings
had been demolished or were not intact.
Sonrise Industrial Center/20010-16-042/24Oet2023

Mill 1 and Northern Area:
The risk calculations indicated the following based on available data, including the
following media: groundwater, residual soil, sub -slab vapor and indoor air (crawl space)
samples.
Risk for Individual Pathways 1
Version Date: July 2022
Basis: May 2022 EPA RSL Table
Site ID: 20010-16-042
Ex sure Unit ID: Mill 1/Northern Area
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
________ Soil
Groundwater Use*
1.5E-04
3.8E-01
YES
8.0E-05
1.7E+00
YES
Non -Residential Worker
Soil
8.7E-06
2.8E-02
NO
Groundwater Use*
1.8E-05
3.7E-01
NO
Construction Worker
Soil
3.9E-07
2.1E-01
NO
Recreator/Trespasser
Soil
8.2E-05
2.1E-01
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
2.6E-05
1.7E+00
YES
Soil Gas to Indoor Air
9.6E-07
3.4E-02
NO
Indoor Air
2.4E-05
6.9E-01
NO
Non -Residential Worker
Groundwater to Indoor Air
5.9E-06
4.0E-01
NO
Soil Gas to Indoor Air
7.3E-08
2.7E-03
NO
Indoor Air
5.6E-06
1.6E-01
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Eyceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NC
Source Groundwater
Exceedence of 2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NC
Source Groundwater
Exceedence of 213 at Receptor?
NC
The Mill 1 and Northern Area risk calculator summary output indicates that the
maximum acceptable regulatory carcinogenic risk range of lE-4 is exceeded for the
direct residential soil exposure pathway, and the non -cancer hazard index (HI) threshold
of 1.0 is exceeded for the direct residential groundwater exposure pathway. The
calculated vapor intrusion risk output indicates that the non -cancer HI threshold of 1.0 is
exceeded for the residential groundwater to indoor air exposure pathway. Although the
residential exposure pathways are exceeded, the intended reuse of the site is for non-
residential only.
Although indoor air data is very limited, and the hazard indices for both residential (0.69)
and non-residential exposures (0.16) is less than the regulatory threshold level of 1, the
risk calculator output falls between 0.1 and <1.0 for this category. This is generally
where Brownfields is not requiring, but is recommending, that a vapor intrusion
mitigation system (VIMS) be installed, particularly if TCE is a known site contaminant.
6
Sonrise Industrial Center/20010-16-042/240et2023

In this area of the Brownfields Property, the risk is driven by the concentrations of
naphthalene in the crawl space sample, although TCE has been present as recently as
2016 in well MW-1 near Mill 1.
Mill 2 and Eastern Area:
The risk calculations indicated the following based on available data, including the
following media: groundwater, limited residual soil and sub -slab vapor samples.
Risk for Individual Pathways 717 M.,
Version Date: July 2022
Basis: May 2022 EPA RSL Table
Site ID: 20010-16-042
Ex sure Unit ID: Mill 2/Eastern Area
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Soil
1.1E-05
2.1E-01
NO
Groundwater Use*
6.6E-08
3.7E-02
NO
Non -Residential Worker
Soil
2.4E-06
1.6E-02
NO
Groundwater Use*
1.8E-08
I 8.0E-03
NO
Construction Worker
Soil
4.0E-07
1.6E-01
NO
Recreator/IYespasser
Soil
6.0E-06
1.2E-01
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathw
Carcinogenicay Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
5.0E-08
2.5E-02
NO
Soil Gas to Indoor Air
3.5E-06
1.1E-01
NO
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
1.1E-08
5.9E-03
NO
Soil Gas to Indoor Air
2.7E-07
8.9E-03
NO
Indoor Air
NC
NC
NC
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NC
Source Groundwater
Exceedence of 2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NC
Source Groundwater
1 Exceedence of 213 at Receptor?
NC
The Mill 2 and Eastern Area risk calculator summary output indicates that neither the
maximum acceptable carcinogenic risk of lE-4 nor the non -cancer HI regulatory
threshold of 1.0 is exceeded for any of the direct exposure pathways for soil or
groundwater. In addition, the carcinogenic risk and non -cancer HI thresholds are not
exceeded for the residential and non-residential worker exposure pathways for vapor
intrusion.
7
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Mill 3, Mill 5, Slasher Building and Delta 4 Finishing Plant:
The risk calculations indicated the following based on available data, including the
following media: groundwater, residual soil, and sub -slab vapor samples.
Risk for Individual Pathways 1
Version Date: January 2022
Basis: November 2021 EPA RSL Table
Site ID: 20010-16-042
Ex sure Unit ID: Mills 3&5, Slasher Bldg., and Delta 4 Finishing Plant
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardindex
Risk exceeded?
Resident
Soil
2.7E-05
8.0E-01
NO
______
Groundwater Use*
6.8E-03
1.2E+03
YES
Non -Residential Worker
Soil
4.3E-06
6.4E-02
NO
Groundwater Use*
1.2E-03
2.7E+02
YES
Construction Worker
Soil
7.9E-07
4.1E-01
NO
Recreator/Trespasser
Soil
1.5&OS
4.4E-01
NO
________
Surface Water*
_
0.0E+00
0.0E+00
NO
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
3.0E-03
6.9E+02
YES
Soil Gas to Indoor Air
1.0E-04
3.7E+00
YES
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
5.1E-04
1.6E+02
YES
Soil Gas to Indoor Air
--------------------------------------------
Indoor Air
7.6E-06
-----------------
NC
3.0E-01
---------
NC
NO
------------
___NC
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NC
Source Groundwater
Exceedence of 2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NC
Source Groundwater
Exceedence of 2B at Receptor?
NC
The Mill 3, Mill 5, Slasher Building and Delta 4 Finishing Plant risk calculator summary
output indicates that the maximum acceptable regulatory carcinogenic risk range of 1 E-4
and the non -cancer HI threshold of 1.0 are exceeded for the direct residential and non-
residential worker groundwater exposure pathways. The drivers for these exceedances are
mainly attributed to both TCE and PCE.
The calculated vapor intrusion risk output indicates that the acceptable regulatory
carcinogenic risk range of lE-4 and the non -cancer HI threshold of 1.0 are exceeded for
the residential and non-residential groundwater to indoor air exposure pathway. The risk
drivers for these exceedances are TCE and PCE. The non -cancer HI threshold exceeds
the residential soil gas to indoor air pathway with the risk driver being naphthalene. The
calculated carcinogenic risk for the residential soil gas to indoor air pathway is equal to
the maximum acceptable threshold of lE-4 and exceeds the non -cancer HI threshold
value of 1.0. However, the calculated values for the soil gas to indoor air pathway for
non-residential exposures does not exceed the acceptable carcinogenic risk of 1E-04, nor
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Sonrise Industrial Center/20010-16-042/240et2023

the threshold HI value of 1.0. The HI of 0.3 does fall within a range in which a VIMS is
recommended to mitigate the risk of vapor intrusion, though it is not required. Further, as
previously noted, the intended reuse of the Brownfields Property will be only for non-
residential uses and not for residential land use.
Fabricating Plant, Fabricating Plant Annex, Distribution Warehouse and Maintenance
Shop:
The risk calculations indicated the following based on available data, including the
following media: groundwater, sub -slab vapor and indoor air samples. A soil sample (B8)
was collected in this area; however, there were no detections in this sample.
Risk for Individual Pathways 1
Version Date: July 2022
Basis: May 2022 EPA RSL Table
Site ID: 20010-16-042
Ex sure Unit ID: Fabricating Plant/Annex, Distribution Warehouse, Maint. Shop
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carciinsogenic
Ri
Hazardtndex
Risk exceeded?
Resident
Soil
NC
NC
NC
Groundwater Use*
3.6E-07
2.0E-02
NO
Non -Residential Worker
Soil
NC
NC
NC
Groundwater Use*
8.5E-08
4.7E-03
NO
Construction Worker
Soil
NC
NC
NC
Recreator/Trespasser
Soil
NC
NC
NC
------------
Surface Water*
NC
NC
---
NC
VAPOR INTRUSION CALCULATORS
Receptor
Path-AnyCarcinogenic
RiskRisk
Ilazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
1.5E-07
1.6E-02
NO
----------
Soil Gas to Indoor Air
9.1E-05
----
5.9E+00
----
YES
Indoor Air
1.6E-05
6.6E-01
NO
Non -Residential Worker
Groundwater to Indoor Air
3.5E-08
3.7E-03
NO
Soil Gas to Indoor Air
7.0E-06
4.7E-01
NO
Indoor Air
3.5E-06
1.6E-01
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NC
Source Groundwater
Exceedence of 2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NC
Source Groundwater
Exceedence of 213 at Receptor?
NC
The Fabricating Plant, Fabricating Plant Annex, Distribution Warehouse and
Maintenance Shop risk calculator summary output indicates that neither the maximum
acceptable carcinogenic risk of IE-4 nor the non -cancer HI regulatory threshold of 1.0 is
exceeded for direct residential and non-residential exposure pathways for groundwater.
Soil samples have not been collected from beneath these buildings.
The calculated vapor intrusion risk output indicates that the non -cancer HI regulatory
threshold of 1.0 is exceeded for the residential soil gas to indoor air exposure pathway,
9
Sonrise Industrial Center/20010-16-042/240et2023

but the site reuse will not be residential. Although TCE, PCE, and other petroleum
hydrocarbon compounds are present in sub -slab vapor, the carcinogenic risk driver for
this exposure pathway is the concentration of ethylbenzene and for the non -cancer
pathway, the high concentration of xylenes.
The non-residential soil gas to indoor air HI of 0.47 falls within the range where we
recommend, but do not require a VIMS. Specific redevelopment plans for this
Brownfields Property, including how any large spaces may be partitioned, have not been
shared with the Brownfields Redevelopment Section to date. An understanding of such
plans and pre -occupancy and post -occupancy sampling will help to confirm the need for
a VIMS.
Indoor air data collected from within the existing buildings at the Brownfields Property
are very limited; the calculated HIs for both residential (0.66) and non-residential
exposure pathways (0.16) in this area of the Brownfields Property are less than the
regulatory threshold level of 1 and fall within the range between 0.1 and <1.0. Generally,
under these circumstances, Brownfields would not require, but would recommend that a
VIMS be installed, particularly if TCE is a known site contaminant. In this area of the
Brownfields Property, the indoor air calculated risk values are driven by the
concentrations of naphthalene and chloroform. TCE and PCE were detected in low
concentrations in the indoor air sample from the maintenance shop, and although both of
these compounds are detected in groundwater at the Brownfields Property, neither were
detected in soil gas samples collected near the maintenance shop, suggesting that the TCE
and PCE may arise from an indoor air contaminant and not from vapor intrusion at this
location.
10
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Southern Reservoir:
The risk calculations indicated the following based on available data, including the
following media: surface water and sediment samples.
Risk for Individual Pathways 1
Version Date: July 2022
Basis: May 2022 EPA RSL Table
Site ID: 20010-16-042
Ex sure Unit ID: Southern Reservoir- Surface Water/Sediment
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardindex
Risk exceeded?
Resident
Soil
7.4E-04
1.5E+00
YES
----- ---- ________
Groundwater Use*
NC
NC
----
NC
Non -Residential Worker
Soil
3.8E-05
1.1E-01
NO
Groundwater Use*
NC
NC
NC
Construction Worker
Soil
6.2E-05
6.5E-01
NO
Recreator/Trespasser
-------- Soil
-------------
Surface Water*
4.1E-04
1.3E-05
8.0E-01
9.9E-01
YES
------
NO
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
CarcinogenicRisk
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
--------------------------------------------
Indoor Air
_
NC
------------------
NC
_
NC
------------------
NC
NC
------------------
NC
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NC
Source Groundwater
Exceedence of 2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NC
Source Groundwater
Exceedence of 2B at Receptor?
NC
The Southern Reservoir risk calculator summary output indicates that the maximum
acceptable regulatory carcinogenic risk range of lE-4 and the non -cancer HI regulatory
threshold of 1.0 are exceeded for direct residential and non-residential soil exposure
pathways, which in this case represents sediment samples collected from the reservoir.
The risk driver for the exceedances is attributed to the presence of hexavalent chromium
in these sediment samples. Additionally, the maximum acceptable carcinogenic risk for
exposure to surface water is not exceeded, but the non -cancer HI threshold is nearly
exceeded with a calculated value of 0.99.
Sonrise Industrial Center/20010-16-042/240ct2023

Southern Property Boundary:
The risk calculations indicated the following based on available data, including the
following media: groundwater.
Risk for Individual Pathways 1
Version Date: July 2022
Basis: May 2022 EPA RSL Table
Site ID: 20010-16-042
Exposure Unit ID: Southern Property Boundary
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
carcinogenic
Risk
Hazardindex
Risk exceeded?
Resident
Soil
NC
NC
NC
--------------------
Groundwater Use*
-
6.1E-06
2.1E-01
NO
Non -Residential Worker
Soil
NC
NC
NC
Groundwater Use*
1.2E-06
4.5E-02
NO
Construction Worker
Soil
NC
NC
NC
Recreator/Trespasser
Soil
NC
NC
NC
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS qF
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
2.3E-07
1.0E-01
NO
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
Non-Residential Worker
Groundwater to Indoor Air
5.2E-08
2.4E-02
NO
- ---
Soil Gas to Indoor Air
----------------Indoor Air ------------
------------------
NC
------NC ------
- --
NC
------NC-------
NC
-----1vC----
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NC
Source Groundwater
Exceedence of 21, at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NC
Source Groundwater
Exceedence of 2B at Receptor?
NC
The Southern Property Boundary risk calculator summary output indicates that neither
the maximum acceptable carcinogenic risk of IE-4 nor the non -cancer HI regulatory
threshold of 1.0 is exceeded for residential nor non-residential direct exposure pathways
for groundwater. In addition, the vapor intrusion carcinogenic risk and non -cancer HI
thresholds are not exceeded for the residential and non-residential worker exposure
pathways based on the groundwater to indoor air calculations.
Land Use Restrictions:
The Brownfields Agreement (BFA) will include the standard land use restrictions (LUR)
regarding land uses, the requirement for an approved Environmental Management Plan,
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. In addition, prohibition
of the use of the Brownfields Property for childcare or adult care centers, schools or
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residential use is prohibited without the proper closure of the onsite reservoirs and written
DEQ approval. Drycleaning operations using chlorinated solvents are also prohibited.
Based on the site -specific data provided to the Brownfields 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:
Based on the calculated risk values across the Brownfields Property and that the intended
reuse of the site is for non-residential purposes only, a VIMS is not being required for the
existing buildings at the Brownfields Property.
However, the PD is negotiating a sale of the Brownfields Property to a buyer at the time
this is being prepared, and a specific redevelopment plan has not yet been shared with the
Brownfields Redevelopment Section. Once additional information as to the details of the
redevelopment plans are known with respect to existing buildings (partitioning the space,
location of any new penetrations through the existing slabs, etc.), further evaluation of the
potential for vapor intrusion would be required to confirm the site is safe for its intended
reuse. Included in that evaluation would be representative indoor air sampling once the
tenant spaces in the existing buildings are built out, and HVAC units are operating, but
prior to occupancy.
A VIMS will be required for new construction, if those buildings are planned to be
constructed over known contaminated areas.
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