25067_Dynatech III_Dec Memo 20230425

DRAFT DECISION MEMORANDUM
DATE: April 25, 2023
FROM: Carolyn Minnich TO: BF Assessment File

RE: Dynatech III 2205, 2209, & 2301 Toomey Ave 660 & 704 West Tremont Ave Charlotte, Mecklenburg County
BF # 25067-21-060
Based on the following information, it has been determined that the above referenced site, whose intended use is for no uses other than for office, retail, hotel, open space, restaurant, beverage or food production facility, parking, recreation, warehousing,
industrial, institutional, high density rental residential, for rent only townhome and, with
prior DEQ approval, other commercial uses, can be made suitable for such uses. Introduction: The Brownfields Property is approximately 6.458 acres in Charlotte, North Carolina and
identified by the Mecklenburg County GIS as Parcel Identification Numbers (PINs) as
follows: Address Parcel Identification Number
2205 & 2209 Toomey Avenue 11906424
660 & 704 West Tremont Avenue 11906420
Portion of 2213 Toomey Avenue Dynatech Brownfields Property 02002-98-060 No Parcel ID

Figure 1 Property Boundaries between Dynatech (02002-98-060), Dynatech III (25067-21-060) The Brownfields Property lies near and to the northeast of the intersection of I-77 and Remount Road. The area contains commercial, light industrial, residential, and vacant land, which was previously developed.

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The Prospective Developer (PD) is 704 West Tremont Owner, LLC, a member-managed Delaware limited liability company that has been qualified to transact business in the
State of North Carolina. 704 West Tremont Owner, LLC’s sole member is Toomey
Multifamily JV, LLC. Redevelopment Plans:
Redevelopment activities include construction of new, high‐density rental residential
buildings, new access roads, parking and landscaped areas. The residential units will be rental only. The PD intends to install a methane mitigation system/vapor mitigation system in the new residential buildings.
In addition, a portion of the former Dynatech Brownfields Agreement (02002-98-060) is
included in the current Dynatech III Brownfields Property footprint. The former agreement will be superseded in its entirety for the portions of redrawn property lines with the proposed Dynatech III Brownfields Agreement. The remaining portions is the subject of Dynatech II Project No. 25001-21-060. The figure above with red and blue
lines depicts the changes in boundaries.

Figure 2 Proposed Redevelopment Plans
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Site History: The Dynatech III parcels were undeveloped land from as early as 1905. Development
began in 1931 and consisted primarily of residential properties and a single commercial
property. Several row houses on 704 W. Tremont Avenue constructed by 1943 were razed in 1993 and a warehouse was constructed in 1994 that was recently demolished in connection with redevelopment. In 2006 a trailer and material storage yard were identified on 2207 Toomey Avenue. Former tenants of the Brownfields Property included
a shoemaker, a plumbing and heating company, a fencing and grading company, and a
trucking company. Former tenants of 2213 Toomey Avenue include haulers of household goods, operators of textile machinery, and Dynatech Industries. The fencing and grading company disposed of materials qualifying as “beneficial fill”
under 15A NCAC 13B.0562 at an average depth of seven feet below ground surface in an
approximately 0.161-acre area depicted on the plat component of the Notice of Brownfields Property referenced below in paragraph 17 as documented in a Solid Waste Disposal Record recorded on April 10, 1995 in the Mecklenburg County land records, Book 8111, Page 223.

The Dynatech Brownfields Property (located at 2213 Toomey Avenue) was developed for industrial use in 1969 and was occupied by Eastern Transit Storage from 1968 to 1973, Frank G.W. McKittrick Textile Machinery from 1973 to 1985, Dynatech Industries, Inc. from 1985 to 1990, and RG Automation/Carolina Custom Tank from
1996 to present. Dynatech Industries performed chrome plating of compressor parts
during its time at the site, generating hazardous waste and reportedly discharging waste to a septic system located on the 2315 Toomey Avenue parcel. Assessments carried out at the Dynatech parcel in the 1990s identified metals and methyl ethyl ketone (MEK) impacts to the subsurface. Removal remedies were conducted for soil, groundwater, and
wastewater in the early 1990s and the site was granted No Further Remedial Action
Planned (NFRAP) status under the federal Superfund Program in 1994. The Dynatech parcel entered into the North Carolina Brownfields Program in 1998. As stated in the Introduction and shown on Figure1. Dynatech III Brownfields Property has portions for the former Dynatech Brownfields Property.

Several Brownfields Properties are adjacent and near to the Dynatech III Brownfields Property. The following table lists number, name, address, and recordation information. BF Number BF Name Address Recorded Date Deed Bk
20045-16-060 Powers Site 436 W Tremont Ave 10/6/2017 32177/574
21022-17-060 Adams Property 510 W Tremont Ave 1/4/2023 37870/309
17002-13-060 Toomey Ave 2240-2250 Toomey Ave 6/9/2017 31867/547
02002-98-060 Dynatech 2213 Toomey Ave 10/17/2003 16323/290
25001-21-060 Dynatech II 2213 Toomey Ave Active Eligible Not recorded
25068-21-060 Dynatech IV 2320 Toomey Ave Active Eligible Not recorded
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Figure 3 Brownfields Site in the surrounding area Environmental Assessment In December 2020, Partner Engineering (Partner) completed a Phase I Environmental
Site Assessment (ESA). According to information provided in the Phase I ESA, the multifamily parcels consisted primarily of single-family residences from the early 1930 through 2014. A commercial building (2315 Toomey/728 West Tremont) was constructed on the multifamily parcels in the early 1990s. Results of the Phase I ESA identified the following recognized environmental conditions (RECs) in connection with
the Site:
• The site reconnaissance of the 2207 Toomey Avenue parcel found above-ground storage tanks (ASTs) and 55-gallon steel drums in an area with heavy vegetation that prevented observations of soil conditions that might have indicated releases.
The presence of drums and ASTs therefore constituted a REC.
• The Adams Brownfields property located on the southeastern adjacent property, has documented methane gas and elevated concentrations of volatile organic compounds in the subsurface. The potential for impact to the Site from documented impacts on the adjacent Adams Brownfields property was identified
as an environmental concern.
• The Powers Site Brownfields property has documented methane gas in the subsurface. The potential for impact to the Site from documented impacts on the adjacent Powers Site Brownfields property was identified as an environmental
concern. To address environmental concerns identified Partner conducted a Phase II Subsurface Investigation in January 2021. Phase II assessment activities included collection of soil, groundwater, and exterior soil gas samples for laboratory analysis and test pits for
geotechnical exploration. In addition, landfill gas and pressure measurements were collected from exterior soil gas monitoring points to evaluate the potential for methane gas in the subsurface. Results of the Phase II assessment activities identified the following:
• Semi Volatile Organic Compounds (VOCs) were identified at concentrations
exceeding the DEQ IHSB Residential Preliminary Soil Remediation Goals
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(PSRGs in soil samples collected near the septic system in the southwestern portion of the Site.
• Groundwater analytical results identified total chromium at concentrations above the North Carolina 2L Standard in a sample collected near the on-Site septic system (B-2GW). Total chromium and lead were also detected in a groundwater sample collected in the northwestern portion of the multifamily parcels (B-4GW)
at concentrations above the 2L Standards. According to information provided in
the report, the detected metals concentrations are likely due to elevated turbidity in the samples submitted for laboratory analysis.
• Results of soil gas sampling identified vinyl chloride and benzene at concentrations above the DEQ DWM Residential Vapor Intrusion Sub-Slab and
Exterior Soil Gas Screening Levels (SGSLs) in the northern portion of the Site. Low levels of 1,3-butadiene were also detected at concentrations above the DEQ DWM Vapor Intrusion Residential and/or Non-Residential SGSLs in several soil gas samples collected at the Site. This is a common contaminant detected from newly installed wells. Ethylbenzene was also detected at a concentration above
the DWM Vapor Intrusion Residential SGSL in the northern part of the multifamily parcels.
• Results of landfill gas readings identified the presence of methane at a concentration of 0.672 percent by volume air in one soil gas monitoring point
location. Methane was not detected at concentrations above the Lower Explosive Limit (LEL) of 5 percent by volume air in subsurface soil gas measurements.
• Test pit exploration found geotechnically unsuitable soils due to debris (wood, masonry, etc.) to depths between approximately 2 and 8 ft below ground surface
(bgs) in the northern portion of the multifamily parcels and to a depth of 16 feet
bgs in the south-central portion of the multifamily parcels.
• In addition, Partner identified the discharge of hazardous plating waste to an on-Site septic system located in the southeastern portion of the multifamily parcel to represent a controlled REC (discussed further below).
In May 2021, Partner performed a Methane Assessment at the Dynatech II and III Brownfields Properties. Assessment activities included installation and sample collection from nineteen landfill gas monitoring points (MSG-4 through MSG-22). The Methane Assessment found limited areas surrounding the Dynatech facility with methane
detections. Most of the detections constituted probable transient-level readings, above background but below Brownfields guidance benchmarks. A single persistent detection of methane at approximately 36-38 %bv occurred in MSG-16 (5 ft bgs) on the northwest part of the property. Two other locations, MSG-8 and
MSG-18, respectively to the southwest and northeast of the Dynatech facility, had methane detections above 1.25 %bv and below 30 %bv. The assessment delineated relatively limited areas affected by methane that coincide with known debris burial areas. The maximum static pressure measured was 0.44 in of water at MSG-16. No other
sample locations indicating static pressure above background or negligible levels were
observed, including at the two other sample locations with methane detections above 1.25% bv (MSG-8 and MSG-18). The static pressure reading observed during prior subsurface assessment at MVSG-7 was not replicated at the immediately adjacent MSG-
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17 location during the Methane Assessment. Other static pressure conditions presented as negative numbers, which indicate vacuums, suggesting that there is not an ongoing
pressure generating source of methane at the site.
In June 2021, Partner performed Brownfields assessment activities on the property. Assessment activities included advancement of six soil borings and 32 characterization soil borings for a total of six soil samples and sixteen soil characterization samples
selected for laboratory analysis. Assessment activities also included groundwater sample
collection from four monitoring wells. Additionally, soil gas samples were collected on the northeastern portion of the Site from four soil gas sample points previously installed by Partner during the May 2021 Methane Assessment.
In November 2022, Partner completed a Methane Mitigation System (MMS) design
report. They system is currently being installed in 2023. Potential Receptors: Potential receptors are: construction workers, on-site workers, future residents, visitors,
animals (dog park/farm animals), and trespassers.
Contaminated Media: DEQ has evaluated data collected from the following media at the subject property: soil, groundwater, and soil gas (both methane and TO-15). DEQ relies on the following data to
base its conclusions regarding the subject property and its suitability for its intended
reuse. Please see the Brownfield Agreement’s Exhibit 2 for specific sample locations, dates, and contaminants of concern (COCs). Soil
• SVOCs were detected in subsurface soil above Residential PSRGs or above laboratory detection limits that have no PSRG. PAH detections include: benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, dibenz(a,h)anthracene, indeno(1,2,3-cd)pyrene, phenanthrene and p-isopropyltoluene

• The following metal concentrations were detected in subsurface soil above Residential PSRGs: arsenic, hexavalent chromium, lead. Arsenic concentrations are consistent with background detections in the surrounding area.

• Twenty-nine soil samples collected across the property in 2020-2021. Soil samples were analyzed to aid in the in-situ characterization for soil export. Over 10,000 cubic yards of soil will be exported off site during redevelopment and
done in accordance with the approved EMP.
• Soil samples were collected in 1994 during the Dynatech remedial investigated and results indicated concentrations of cadmium and total chromium above soil
PSRGs. Historical reports have laboratory data sheets, but no soil boring logs
were available for review. These detections were not replicated in the 2020 in-situ sampling event.
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Sediment
• Sediment samples were collected from the unnamed intermittent perennial stream that flows to Irwin Creek on the Brownfields Property. Arsenic and benzo(a)pyrene concentrations were detected above
Residential PSRGs. These samples were collected on the Dynatech II
Brownfields Property and technically not on the brownfields property for this decision memo. See figure to the right for location. Surface Water
• An unnamed intermittent perennial stream is on the eastern portion of the Brownfields Property and trends generally north-south toward Irwin Creek. Surface water samples were collected and no detections above 2B Surface Water Quality Standards.
Groundwater
• No VOCs were detected in groundwater above 2L Groundwater
Quality Standards. The following were detected above laboratory method detection limits and do not have screening values: acetone, benzyl alcohol, fluoranthene, and pyrene.
• Metals were detected in groundwater above 2L Groundwater Quality Standards:
chromium and lead.

Vapor Blue shaded area is Dynatech III, proposed for multi-family high density residential use Green shaded area is Dynatech II, propose for non-residential use
Exterior Soil Gas
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• Partner installed and collected soil gas samples within or near the footprint of
proposed multi‐family buildings and existing Site buildings.
• The soil gas monitoring points were also used to measure landfill gas concentrations in the subsurface. The soil gas samples were collected from approximately 5 to 10 ft bgs. o 1-3-Butadiene was detected in soil gas samples collected in the eastern
and western portions of the property at concentrations that exceed the DEQ DWM Residential SGSLs of 3.1 µg/m3. o Benzene (up to 189 µg/m3) was detected at concentrations above the DEQ DWM Residential Vapor Intrusion SGSL of 12 µg/m3 in samples collected in the eastern portion of the property.
o Naphthalene (up to 12.5 µg/m3) and vinyl chloride (up to 10.8 µg/m3) were detected at concentrations above the DEQ DWM Residential Vapor Intrusion SGSLs of 2.8 µg/m3 and 5.6 µg/m3, respectively. o Ethylbenzene was detected slightly above the Residential Vapor Intrusion SGSL of 37 µg/m3.
o No other VOCs were detected at concentrations above the DEQ DWM Residential or Non‐Residential Vapor Intrusion Soil Gas Screening Levels (SGSLs). Methane
• In February, ten soil gas points were installed to specifically collect and analyze fir methane. Methane was below detections limits for nine of 10 samples and was found at 0.672 percent by volume (Less than the Brownfields Program threshold criteria of 1.25 percent by volume as a residential passive mitigation threshold) at a monitoring point on the southwestern part of the parcels. For reference, methane
is considered combustible between a Lower Explosive Limit of 5 percent and an Upper Explosive Limit of approximately 15 percent by volume. Static pressure was found as an apparent anomaly with uncertain origins at one location; otherwise, the readings were negligible across the dataset.
• In May 2021, nineteen methane monitoring points were installed and sampled on
the Brownfields Property. Methane was detected in excess of the lower explosive limit (LEL) of 5% in 3 sample locations.
• The maximum static pressure measured was 0.44 in of water at MSG-16. No
other sample locations indicating static pressure above background or negligible
levels were observed, including at the two other sample locations with methane detections above 1.25% bv (MSG-8 and MSG-18). The static pressure reading observed during prior subsurface assessment at MVSG-7 was not replicated at the immediately adjacent MSG-17 location during the Methane Assessment. Other static pressure conditions presented as negative numbers, which indicate
vacuums, suggesting that there is not an ongoing pressure generating source of methane at the site.
• Methane is thought to be occurring due to the fill materials that are present on the
adjacent brownfields property to the southeast. Methane mitigation measures are
required at the Adams Brownfields Property and Powers Brownfields Property.

Sub-Slab Vapor No sub-slab vapor testing was completed.
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Indoor Air
No indoor air sampling was completed.
Risk Calculations: Risk calculations were performed using the January 2022 DEQ Risk Calculator https://deq.nc.gov/permits-rules/risk-based-remediation/risk-evaluation-resources.
For the purposes of looking at the site spatially, the site was not divided into areas. Two
risk calculators were completed for the property. First one was worst case for all media, soil, groundwater, and vapor. The second risk calculator removed soil that was hauled off site during redevelopment phrase. The soil was properly disposed of at local municipal solid waste landfill (MSWLF). Disposal tickets and waste manifest are in the
Redevelopment Summary Report.
The risk calculations indicated the following based on available data, including the following media: groundwater, residual soil (based on confirmatory soil data), exterior soil gas, sub-slab vapor, sediment, and surface water samples

1) Risk Calculator with impacted soils before redevelopment activities.

2) Risk Calculator with soils remaining on the property after export for development.
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3. The remaining issue is residential use vapor pathway for soil gas to indoor air. The risk driver is 1-3 Butadiene detections. This can be a common interference contaminate from newly installed wells. If this chemical is removed from the risk calculator, then the hazard quotient is below 1. The PD has already commented to a MMS and VIMS for residential buildings.

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Results from the risk evaluation indicate that residential risk indices were exceeded for groundwater use. An Environmental Management Plan (EMP), approved by DEQ, will
be required before the start of soil grading or excavation activities to prevent exposure to
site workers from unacceptable levels of contaminants, and to manage the safe handling and disposal of potentially contaminated materials during construction. In addition, final grade sampling of exposed shallow soil will be required. Groundwater use will be prohibited through land use restrictions. Due to the presence of methane on the
brownfields property as discussed above, a methane mitigation plan is required.
Land Use Restrictions:
The standard land use restrictions as to land use, no physical redevelopment without an EMP, reporting, prohibitions on groundwater use, restrictions on soil disturbance, vapor intrusion provisions, known contaminant uses, notices, access, and land use restriction
update provisions will be included.
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 ISSUES
EMP approved and signed on 10/19/2021.
The Methane Mitigation System design was accepted and signed in November 2022. The design plans support passive ventilation of subsurface gases below planned impervious surfaces (e.g., parking areas, sidewalks, etc.) surrounding the buildings.