23010_Raleigh Union Station Bus_DM_20231030

DECISION MEMORANDUM
DATE: October 30, 2023
FROM: Stephanie Graham
TO: BF Assessment File
RE: Raleigh Union Station (RUS) Bus
200 S. West Street
Raleigh, Wake County
BF # 23010-19-092
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than for a multi -modal public transportation
center, retail, office, beverage or food production facility, restaurant, cocktail bar, event
space, hotel, childcare, adult care, educational space, parking, high -density residential
with affordable housing units consistent with local zoning conditions, health care facility,
grocery, recreation, and subject to DEQ prior written approval, other commercial uses,
can be made suitable for such uses.
Introduction:
The Prospective Developer (PD) is Research Triangle Regional Public Transportation
Authority dba GoTriangle, located at 4600 Emperor Boulevard, Suite 100, Durham, NC
27703. Its President and CEO is Charles Lattuca of the same address. The 1.739-acre
Brownfields Property is located at 200 S. West Street, Raleigh, NC and identified by PID
1703488236. The Brownfields Property was formerly comprised of three parcels located
at 200, 206 and 210 S. West Street, Raleigh, NC and identified by PIDs 1703488450,
1703488314 and 1703488250, respectively; however, in the Fall of 2023, these parcels
were combined into the one parcel referenced above.
The Brownfields Property consisted of three former commercial/warehouse buildings
with full and/or partial basements. These structures were demolished, with the exception
of building facades, under an Environmental Management Plan (EMP) approved by DEQ
on April 18, 2022. A second EMP for construction activities was provided July 28, 2023
with a subsequent revision provided to DEQ for review on October 12, 2023. It was
historically reported that the Brownfields Property was impacted by former offsite dry-
cleaning operations and/or petroleum releases associated with the northern and western
adjacent properties. However, 2021 data has not confirmed a continued impact from these
chlorinated solvent releases.
Additionally, the Brownfields Property is surrounded by three adjacent Brownfields sites
identified as Warehouse District ( BF# 16023-12-092) to the north, Dillion Station (BF#
18056-14-092) to the east and Raleigh Union Station (BF# 17031-13-092) to the
south/southwest. Chlorinated solvents, polycyclic aromatic hydrocarbons (PAHs) and
petroleum contamination were noted on these adjacent Brownfields Properties; however,
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it does not appear that these contaminants have significantly impacted the RUS Bus
Brownfields Property.
Redevelopment Plans:
The PD plans to redevelop the property with a multi -modal public transportation center,
retail, office, beverage or food production facility, restaurant, cocktail bar, event space,
hotel, childcare, adult care, educational space, parking, high -density residential with
affordable housing units consistent with local zoning conditions, health care facility,
grocery, recreation, and subject to DEQ prior written approval, other commercial uses.
The Brownfields Program understands that the PD is planning on installing a vapor
intrusion mitigation system. We concur with this plan, based on the risk calculator
results, and will be requesting that the PD follow the NC DEQ Brownfields Vapor
Intrusion Assessment Work Plan & Report Checklist.
Site History:
Previous uses of the northern area of the Brownfields Property include ice and
refrigeration companies (1896-1914), a casket manufacturer (1920-1981), a likely
plumbing supply company (1986-1991), a design company (1997-2002) and a restaurant
(2003-2020). Previous uses of the 206 and 210 S. West Street buildings include a window
coverings company (1896), a spoke factory (1903), a biscuit company (1909-1914), a
monument facility (1914) and a warehousing and retail sales of forklift truck parts (1936-
early 2000s).
The northern area (previously addressed as 200 S. West Street) is identified on the
Inactive Hazardous Waste Sites Priority List as Raleigh TTA — Wilson Parcel
(NONCD0001124). This listing is associated with groundwater contamination related to
former offsite dry-cleaning operations and/or petroleum releases located on the northern
adjacent property (Dillon A Parcel) that were identified as impacting the northern parcel
of the Brownfields Property. Additionally, a gasoline underground storage tank (UST)
may be located on this northern Brownfields parcel, as documented in a notification
submitted to the Inactive Hazardous Site Branch (IHSB) in 2005. The status or location
of the UST is unknown.
The central and southern areas of the Brownfields Property (previously located at 206
and 210 S. West Street) are identified on the Inactive Hazardous Waste Sites Priority List
as Raleigh TTA — Dillon B Parcel (NONCD0001126). This listing is associated with
groundwater contamination related to a former UST located on the western adjacent
property (Dillion C Parcel) that was identified as impacting these parcels of the
Brownfields Property.
Potential Receptors:
Potential receptors consist of future onsite occupants, including residential tenants,
visitors, construction workers and trespassers.
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Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
groundwater and sub -slab soil vapor. 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.
Soil
Soil data was obtained from 14 samples, including two duplicates, collected on the
Brownfields Property. Five samples were collected at depths between 6-7, 9 and 10 feet
below ground surface (bgs) in 2004, and nine samples were collected at depths between
0-3 and 3-8 feet bgs in 2021. The report summarizing the 2004 data was not signed nor
sealed by an environmental professional, and it was missing the analytical data; therefore,
while reviewed by the Brownfields Program, no data reported from the 2004
investigation was included in the risk calculator or Exhibit 2 to the Brownfields
Agreement.
No volatile organic compounds (VOCs) were detected in soil above their respective NC
Department of Environmental Quality Preliminary Soil Remediation Goals (DEQ
PSRGs) for residential settings. Benzo(a)pyrene was the only semi-VOC (SVOC)
detected above its residential PSRG. Metals detected above the DEQ PSRGs for
residential settings were limited to single digit values of arsenic and values of hexavalent
chromium less than 1 milligram/kilogram (mg/kg). Other compounds for which there is
not an established PSRG were detected in site soil, and these compounds include p-
isopropyltoluene and the PAHs acenaphthylene, benzo(g,h,i)perylene and phenanthrene.
Groundwater
The most recent groundwater assessment was completed in 2021 and consisted of the
collection of four samples, including one duplicate. The samples were collected to
evaluate impacts to the Brownfields Property from the adjacent, offsite releases noted
above. Site groundwater results indicated concentrations of certain PAHs and metals in
excess of their respective NC 2L groundwater standards. The sample event in 2021 did
not confirm the presence of chlorinated VOCs that had been identified in one well (MW-
C-03) that was installed at 200 S. West Street and sampled in 2004. No groundwater
contaminants detected in 2021 at the Brownfields Property exceed the Residential Vapor
Intrusion Screening Levels (VISLs) for VOCs in groundwater.
Surface Water
Surface water is not located on the Brownfields Property.
Exterior Soil Gas
No exterior soil gas samples have been collected. Prior to demolition, the footprint of the
former buildings covered the entire Brownfields Property.
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Sub -Slab Vapor
Six sub -slab vapor samples, including one duplicate, were collected on the Brownfields
Property in 2021. Two of the samples and the duplicate (SV-0I and its duplicate as well
as SV-3) were collected from Vapor Pins, and the three remaining samples (SG-01, SG-
02 and SG-03) were collected 10 feet below the building slabs. Benzene, 1,3-butadiene,
ethylbenzene and n-hexane exceeded their respective residential VISLs for soil vapor.
Other compounds detected in these sub -slab vapor samples were acetone, ethanol, 4-
ethyltoluene, trichlorofluoromethane and 2,2,4-trimethylpentane but there are no
established VISLs for these compounds.
Indoor Air
No indoor air samples were collected in the former Brownfields buildings. With the
exception of several building facades, the former buildings were demolished to make way
for the new redevelopment.
Risk Calculations
Risk calculations were performed using the January 2023 DEQ Risk Calculator
https: Hdeq.nc. gov/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 and found that those
contaminants did not apply to this particular Brownfields Property. Therefore, the risk
calculator output from the January 2023 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 evaluated
as a whole with a site -wide calculator.
The risk calculations indicated the following based on available data, including the
following media: groundwater, soil, and sub -slab vapor. The sub -slab samples were
collected from vapor pins as well as samples collected 10 feet below the slab. The highest
concentrations in the sub -slab samples were identified from the 10-foot samples.
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Risk for Individual Pathways 1
Version Date: January 2023
Basis: November 2022 EPA RSL Table
Site ID: 23010-19-092
Exposure Unit ID: Sitewide GW, Soil and Sub -Slab Vapor
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil
1.5E-05
3.2E-01
NO
Groundwater Use*
7.1E-05
6.3E-01
NO
Non -Residential Worker
Soil
1.4E-06
2.3E-02
NO
Groundwater Use*
5.6E-06
9.4E-02
NO
Construction Worker
Soil
3.6E-07
2.2E-01
NO
Recreator/rrespasser
Soil
8.6E-06
1.8E-01
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carciinnogenic
sk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
1.1E-08
0.0E+00
NO
Soil Gas to Indoor Air
1.9E-05
9.1E-01
NO
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
8.9E- 10
0.0E+00
NO
Soil Gas to Indoor Air
1.4E-06
7.2E-02
NO
Indoor Air
NC
NC
NC
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of2L at Receptor?
NC
Source Groundwater
Exceedence of2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of2B at Receptor?
NC
Source Groundwater
Exceedence of2B at Receptor?
NC
The risk calculator summary output indicates that none of the calculated risk values or
hazard indices exceed the acceptable risk ranges for residential, non-residential worker,
construction worker or receptor/trespasser for direct exposure pathway scenarios. This
output also indicates that there is no unacceptable vapor intrusion risk for residential or
non-residential worker exposure pathways for groundwater to indoor air or soil gas to
indoor air. However, the hazard index for soil gas to indoor air is at 0.91, just below the
threshold value of 1.0. Therefore, we recommend that a vapor intrusion mitigation system
(VIMS) system be installed. The PD plans to install a VIMS.
Land Use Restrictions:
The Brownfields Agreement will include the standard land use restrictions (LURs)
pertaining to approved land uses, which include a reference to the City of Raleigh's
Conditional Use District Zoning Conditions dated September 20, 2019, no physical
redevelopment without an approved EMP, redevelopment reporting, prohibitions on
groundwater use, restrictions on soil disturbance, no soil import/export without DEQ
approval, clean fill cover for any playgrounds or schools, vapor intrusion provisions,
known contaminant uses, notification, access, and LUR update provisions.
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Based on the site -specific data provided to the Brownfields 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 Issues:
An EMP was submitted for the demolition of the existing buildings, which included the
preservation of some building facades, removal of footings and the backfilling of an
existing basement. This EMP was approved on April 18, 2022. A second EMP for
building construction has been provided and is in review.
The EMP confirms the PD will be installing a VIMS, which is recommended by DEQ
due to the hazard index for soil gas to indoor air (0.91) at the Brownfields Property.
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