DERR-2025-002622

REMEDIAL ACTION PLAN
Paxton Development
203 to 225 West Paxton Avenue
Salt Lake City, Utah
Voluntary Cleanup Site #C-129
Prepared for
Paxton Project, LLC
2630 Canyon Road
Springville, Utah
Prepared by
Geosyntec Consultants, Inc.
215 South State Street
Salt Lake City, Utah 84111

Geosyntec Project SLC1091
February 13, 2025
Updated: April 9, 2025

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TABLE OF CONTENTS
ACRONYMS AND ABBREVIATIONS ...................................................................................III
1. INTRODUCTION .................................................................................................................1
1.1 Site Location and Description ......................................................................................1
1.2 Site Background ...........................................................................................................1
1.3 Site Setting ...................................................................................................................1
1.4 Site Geology and Hydrogeology ..................................................................................1
1.5 Site Impacts Summary ..................................................................................................2
1.5.1 Phase I ESA ......................................................................................................3
1.5.2 Site Characterization ........................................................................................3
1.6 Evaluation of Risk Pathways ........................................................................................5
1.6.1 Impacted Media ................................................................................................5
1.6.2 Potential Receptors ...........................................................................................5
1.6.3 Pathways for Exposure .....................................................................................5
1.7 Remedial Action Objectives .........................................................................................6
1.8 Remedial Action Cleanup Goals ..................................................................................6
2. REMEDIAL ACTION COMPONENTS ..............................................................................8
2.1 Building Foundation and Pavement Removal ..............................................................8
2.2 Hydraulic Lift Removal ................................................................................................8
2.3 Shallow Soil Excavation ..............................................................................................9
2.4 Subsurface Soil Excavation ........................................................................................10
2.5 Petroleum Impacted Groundwater Treatment ............................................................11
2.6 Potential Unexpected Impacts ....................................................................................11
2.7 Vapor Intrusion Mitigation .........................................................................................12
2.8 Monitoring Well Abandonment .................................................................................12
2.9 Monitoring Well Installation and Sampling ...............................................................12
2.10 Laboratory Analytical Methods ..................................................................................13
2.11 Quality Control Sampling ..........................................................................................13
2.12 Sample Handling and Custody ...................................................................................13
2.13 Sampling Equipment Decontamination ......................................................................13
3. SITE CONTROL MEASURES ...........................................................................................14
3.1 Health and Safety Plan ...............................................................................................14
3.2 Project Controls ..........................................................................................................14
3.3 Remedial Equipment Decontamination ......................................................................14
3.4 Dust Control ...............................................................................................................14
3.5 Stormwater Control ....................................................................................................14
3.6 Construction Dewatering ............................................................................................15
3.7 Public Involvement .....................................................................................................15
3.8 Materials Management ...............................................................................................15
4. SCHEDULE AND POST REMEDIATION ACTIVITIES ................................................16

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5. REFERENCES ....................................................................................................................17

LIST OF FIGURES
Figure 1: Site Location
Figure 2: Site Layout
Figure 3: Shallow Soil Sample Locations
Figure 4: Subsurface Soil Sample Locations
Figure 5: Groundwater Sample Locations
Figure 6: Soil Gas Sample Locations
Figure 7: Remaining Foundations/Impervious Surfaces and Hydraulic Lifts
Figure 8: Shallow Soil Excavation Area
Figure 9: Proposed Subsurface Soil Excavation Areas
Figure 10: Approximate Future Monitoring Well Locations

LIST OF TABLES
Table 1: Soil Sample Summary with Cleanup Goals
Table 2: Groundwater Sample Summary with Cleanup Goals

LIST OF APPENDICES
Appendix A: Background Arsenic Data
Appendix B: Proposed VIMS Design
Appendix C: Public Notice

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ACRONYMS AND ABBREVIATIONS
bgs Below Ground Surface
COC Constituents of Concern
DERR Division of Environmental Response and Remediation
EPA United States Environmental Protection Agency
ESA Environmental Site Assessment
ISL Initial Screening Level
MCL Maximum Containment Level
QAPP Quality Assurance Project Plan
RAP Remedial Action Plan
RCRA Resource Conservation and Recovery Metals
REC Recognized Environmental Condition
RSL Regional Screening Level
SCR Site Characterization Report
SOP Standard Operating Procedure
TPH-DRO Total petroleum hydrocarbons - diesel range organics
TPH-GRO Total petroleum hydrocarbons - gasoline range organics
TCE Trichloroethene
UDEQ Utah Department of Environmental Quality
UGWQS Utah Groundwater Quality Standard
VCP Voluntary Cleanup Program
VISL Vapor Intrusion Screening Level
VOC Volatile organic compound

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1. INTRODUCTION
On behalf of Paxton Project, LLC (Paxton), Geosyntec Consultants (Geosyntec) has prepared this
Remedial Action Plan (RAP) for the planned Paxton residential development project located at
203 to 225 West Paxton Avenue in Salt Lake City, Utah (Site). This RAP describes the
remediation activities that will address environmental impacts identified at the Site, as well as the
Site Management Plan (SMP) and Environmental Covenant that will be prepared for the Site.
The characterization and remediation of the Site are being conducted under the Utah Department
of Environmental Quality (UDEQ), Division of Environmental Response and Remediation’s
(DERR) Voluntary Cleanup Program (VCP), Voluntary Cleanup Site #C-129.
1.1 Site Location and Description
The Site is approximately 0.71 acres in size and was previously occupied by a towing/auto repair
business (Tucker Towing) and two residential dwellings. The location and boundaries of the Site
are presented on Figure 1. The general layout of the Site and key features are presented on Figure
2. It is noted that the Site buildings and structures were previously demolished down to the
foundations. The footprint of the remaining foundations and concrete/asphalt surfaces are shown
on Figure 7.
1.2 Site Background
Based on historical records, the Site was used for residential purposes dating back to at least 1898.
Towing and/or auto repair operations began at the Site in the 1940s and continued until June 2024
(Atlas 2023). Paxton is planning to redevelop the property with a multi-unit residential/commercial
development and has entered into the DERR VCP to address the impacts that have been observed
at the Site (see Section 1.5) as part of the planned development. The Site was accepted into the
VCP program on April 1, 2024. Drawings depicting the details of the planned future development
were previously submitted to DERR.
1.3 Site Setting
The Site is located approximately 1.5 miles southwest of downtown Salt Lake City, Utah. Land
use in the surrounding area is comprised of a mixture of residential, commercial and light industrial
properties. The general topography of the surrounding area is flat with a slight downward slope to
the west.
1.4 Site Geology and Hydrogeology
The Site is located within the Salt Lake Valley, which is part of the Great Basin physiographic
province of the western United States The valley is bordered on the east and northeast by the
Wasatch Range, to the northwest by the Great Salt Lake, on the west by the Oquirrh Mountains,
and to the south by the Traverse Mountains. The valley is filled with unconsolidated to semi-
consolidated sediments with thicknesses reaching up to 4,000 feet in certain areas. The basin fill
mainly consists of fluvial and lacustrine deposits eroded from the surrounding mountains that

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intermingle with alluvial-fan deposits and, to a lesser degree, deltaic and landslide deposits along
the valley margins. Surface deposits in the center of the valley primarily consist of offshore
lacustrine silt and clay, which were deposited during the Pleistocene Bonneville lake cycle
approximately 12,000 to 29,000 years ago.
Based on subsurface borings from the previous site investigations, surface soils are primarily
composed of fill from approximately 0 to 2 feet below ground surface (bgs). Surface fill is
underlain predominately by clays with minor silty sand and clayey sand zones to approximate
depths of 45 feet bgs (the maximum depth of previous investigations conducted at the Site) (AGEC
2023b).
Groundwater has been observed to be present at depths ranging from approximately 4 to 6 feet bgs
with a relatively flat gradient across the Site (AGEC 2023b and Geosyntec 2024a). Regional
groundwater flow is estimated to be towards the west, based on topography. The nearest surface
water body is the Jordan River, which is located approximately 1 mile west of the Site.
1.5 Site Impacts Summary
This section presents a summary of identified impacts at the Site based on the characterization
activities that have been conducted, including initial due diligence activities conducted by Paxton
prior to acquiring the property and the site characterization activities conducted under the VCP as
outlined below:
Due Diligence Investigations
 A Phase I Environmental Site Assessment (ESA) was performed by Atlas in December
2023 (Atlas 2023).
 Limited Phase II subsurface investigations were performed in September and October
2023 by AGEC (AGEC 2023a and AGEC 2023b). The initial investigation was
conducted in September 2023 and included the completion of five borings to collect soil
and groundwater samples at areas of potential concern. The subsequent investigation was
conducted in October 2023 and included the installation of 10 monitoring wells and the
collection of two surface soil samples from surface-stained areas in the storage yard in
the center of the Site.
VCP Site Characterization
 Site Characterization investigation activities were conducted between July 2024 and
September 2024 (Geosyntec 2024a). These activities included the collection of soil
samples at 16 locations at depths ranging from the ground surface to 18 inches bgs,
collection of groundwater samples from the existing monitoring wells that were installed
during the due diligence investigations, and collection of two soil gas samples.
Details regarding the findings of each of the above investigations are provided in the referenced
reports and are summarized below.

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1.5.1 Phase I ESA
The Phase I ESA identified the following Recognized Environmental Conditions (RECs)
associated with the Site:
 Towing/automotive repair activities were previously conducted at the Site and included the
presence of two former in-ground hydraulic lifts (the former hydraulic lift located in the
southwestern portion of the Site was identified in the Phase I ESA as an “underground
vault”). The location of the lifts is shown on Figure 2.
 The potential for chlorinated solvent impacts from the adjacent former RETEP property,
which is located to the north of the Site at 216 West Paxton Avenue. The RETEP property
is listed on the U.S. Environmental Protection Agency (EPA) Comprehensive
Environmental Response, Compensation and Liability Information System (CERCLIS)
database and has undergone investigation by the EPA and DERR related to chlorinated
solvent impacts to soil and groundwater (Atlas 2023).
1.5.2 Site Characterization
The samples collected during the previous investigation and characterization activities were
compared against the screening levels identified under the VCP, including:
 EPA residential Regional Screening Levels (RSLs);
 EPA Maximum Contaminant Levels (MCLs);
 EPA residential Vapor Intrusion Screening Levels (VISLs); and
 DERR Initial Screening Levels (ISLs).
A summary of the identified impacts for each sample media is presented below. Additional details
are provided in the Site Characterization Report (Geosyntec 2024a).
 Shallow Soil (0 to 18 inches bgs) – Shallow soil sample locations are presented in Figure 3.
Metals (e.g., arsenic, lead and/or cadmium) were observed above the EPA residential RSLs
in all of the soil samples. The maximum detected arsenic, cadmium and lead concentrations
were reported at 34.6 mg/kg, 8.79 mg/kg and 714 mg/kg, respectively. Cadmium exceedances
were identified at one sample location (S-4) from 0 to 6 inches bgs. Lead exceedances were
observed in seven sample locations (S-1, S-3, S-4, S-6, S-7, S-15, and SS-1) at depths of 0 to
6 inches and/or 6 to 12 inches bgs. No lead exceedances were observed at deeper depths, with
the exception of samples S-3 and S-6 from 12 to 18 inches bgs. Arsenic concentrations
exceeded the screening levels at all of the sample locations. It is noted that naturally occurring
concentrations of arsenic are regularly observed exceeding the screening levels in Salt Lake
Valley.
Exceedances for Oil and Grease were detected above the DERR ISL of 1,000 mg/kg at seven
of the 16 sample locations (S-4, S-5, S-6, S-7, S-11, S-12 and SS-1), with reported

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concentrations ranging from 1,250 mg/kg to 11,500 mg/kg. Additionally, total petroleum
hydrocarbons – diesel range organics (TPH-DRO) was also detected above the DERR ISL of
500 mg/kg at sample locations S-5 and S-7 (TPH-DRO concentrations of 542 mg/kg and 1,180
mg/kg, respectively). No exceedances for total petroleum hydrocarbons – gasoline range
organics (TPH-GRO) were detected in any of the sample locations. All of the exceedances
were observed in the samples collected from 0-6 inches, except for location SS-1 where the
exceedance was observed in the 6-12 inch bgs interval. Deeper samples (from 6-12 inches or
12-18 inches) were collected from all of the locations where exceedances were observed,
except for locations S-5 and S-11 (deeper samples were not proposed for these locations). No
DERR ISL exceedances were identified in the deeper samples. Similar to the observed
detections of metals, the data suggests that while detections of Oil and Grease and TPH-DRO
in soil are present in select areas, the impacts do not appear to extend below 12 inches in depth
and in most cases are only present in the upper 6 inches.
Trace detections of one or more volatile organic compounds (VOCs) were detected at all 16
sample locations. However, all of the reported detections were below EPA residential RSLs
for soil indicating that significant concentrations of VOCs are not present in shallow soil. This
is consistent with the samples collected during the initial investigations, which also did not
identify significant VOCs in soil.
 Subsurface Soil – Subsurface soil sample locations are presented in Figure 4. Oil and Grease
was above screening levels at two locations, including: GP-5 from a depth of 7 to 8 feet bgs
(below the water table) and MW-3 from a depth of 1 to 2 feet bgs.
Chlorinated VOC concentrations did not exceed screening levels in any soil samples, with the
exception of the soil sample that was collected in boring GP-4 from 6 to 7 feet below ground
surface (bgs). Trichloroethene (TCE) was detected in this sample at a concentration exceeding
the residential RSL, but below the industrial RSL. This sample appears to have been collected
from below the groundwater table. As discussed below, VOCs have been detected in
groundwater beneath the Site and appear to be related to the adjacent RETEP property. The
subsurface soil samples at all other locations were below screening levels.
 Groundwater – Groundwater sample locations are presented in Figure 5. VOCs were detected
above screening levels in the groundwater samples collected from five borings (GP-1 through
GP-5) seven monitoring wells (MW-2, through MW-8). Petroleum hydrocarbons (TPH-DRO
and/or TPH-GRO) were also observed above screening levels in boring GP-5 and two
monitoring wells (e.g., MW-2 and MW-7). All of the groundwater exceedances were observed
in the uppermost saturated groundwater zone and no significant impacts were identified in the
two monitoring wells screened at deeper intervals within the Site (MW-9 and MW-10). No
significant on-site sources of potential VOC impacts were identified, and the available data
suggests that the observed detections are potentially related to the adjacent RETEP site or
another off-site source.

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 Soil Gas - Soil gas sample locations are presented on Figure 6. Both of the soil gas samples
showed VOCs concentrations above the screening levels. The detection of elevated VOC
levels in soil gas is consistent with the observed groundwater concentrations which also exceed
screening levels.
1.6 Evaluation of Risk Pathways
This section provides a qualitative evaluation of the potential to human and ecological risks based
on the identified Site impacts and the proposed development plan. The risk evaluation was
conservatively prepared assuming no remediation activities at the Site.
1.6.1 Impacted Media
Impacted media at the Site includes shallow soil, subsurface soil, soil gas and groundwater.
Identified constituents of concern (COC) for shallow soil include metals (arsenic, lead and
cadmium) and petroleum constituents (Oil and Grease and TPH-DRO). Identified COCs for
subsurface soil potentially include Oil and Grease and TCE, although these constituents were
detected in samples from below the water table. Identified COCs for groundwater include
petroleum constituents (TPH-DRO and TPH-GRO) and select VOCs. Identified COCs for soil gas
include VOCs.
1.6.2 Potential Receptors
Potential receptors based on the planned development of the Site include future
workers/maintenance personnel and residents. Based on the environmental setting which is urban
in nature and the proposed development plan, there is not expected to be significant ecological
receptors within the Site. Ecological receptors would likely be limited to small mammals, birds or
invertebrates.
1.6.3 Pathways for Exposure
Potential exposure pathways for surface and subsurface soil would include dermal contact,
incidental ingestion, and inhalation of dust for both potential workers/maintenance personnel and
residents. Ecological receptors could also be exposed to surface and subsurface soil, but this
likelihood is considered minimal given the environmental setting and planned development which
includes covering most of the property with site structures or impervious surfaces.
Drinking water for the development will be supplied by the municipal drinking water system and
groundwater will not be used for any purposes. Therefore, ingestion and direct use of groundwater
is not a complete exposure pathway for site receptors. While groundwater will not be used for any
purpose, potential dermal contact or incidental ingestion would be a potentially complete exposure
route for maintenance workers during excavation activities that may encounter groundwater.
Vapor intrusion from groundwater is also a complete exposure pathway for workers/maintenance
personnel and residents. Soil gas could also expose subsurface animals (e.g., vols or subsurface
invertebrates).
An overview of proposed remedies for potential exposure pathways is provided in Section 1.7.

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1.7 Remedial Action Objectives
Based on the identified impacts and risks, this RAP has been developed to achieve the following
objectives and facilitate the development of the Site:
 Remove surface and subsurface soil that exceeds action levels;
 Remove the source and enhance the biodegradation of petroleum hydrocarbon impacted
groundwater;
 Mitigate the vapor intrusion pathway through installation and operation of a vapor
mitigation system; and
 Prevent future groundwater use and provide for long-term management of the Site through
implementation of institutional controls.
The specific remedial action components that will be executed to achieve these objectives are
presented in Section 2.0.
1.8 Remedial Action Cleanup Goals
The proposed remedial action goals for the soil excavation and removal activities are summarized
on Table 1 and are based on the EPA residential RSLs and DERR ISLs, with the exception of
arsenic. For arsenic, which has an EPA RSLs that exceeds typical background soil concentrations
in the Salt Lake City area, the proposed remedial action goal will be based on the average
background arsenic concentration data from the Site and surrounding area as described below.
To develop a representative average arsenic background concentration, Geosyntec reviewed
available data from the following sources:
 Paxton Site – The locations of the soil samples from the Paxton Site were reviewed to
determine if they were potentially representative of background conditions. Of the soil
samples collected from the Site, only one location (sample S-10) is considered potentially
representative of background conditions. Sample S-10 is located within the former
residential property in the northwestern portion of the Site (see Figure 3) that was not
previously utilized for industrial purposes. It is noted that no other constituents were
detected in exceedance of the remedial action goals in the samples from this location. The
detected average arsenic concentration from this sample location was 11.7 mg/kg (average
concentration of two samples collected at this location from depths of 0 to 6 and 6 to 12
inches bgs).
 Surrounding VCP Sites – Geosyntec reviewed data from VCP sites located within 0.75
miles of the Paxton Site. Four VCP sites were identified within this radius where arsenic
background cleanup levels were developed within the last three years, including Liberty

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Corner (VCP Site #C-125), Bumper House and Chrome Works (VCP Site #C-103), Union
Pacific Provo Line (VCP Site #C-109), and Trillium Flow Technologies (VCP Site #C-
109). The arsenic background cleanup levels for these properties are summarized in Table
A-1 (Appendix A) and range from approximately 13 to 35 mg/kg.
 RETEP Property – As part of the DERR and EPA investigation activities at the RETEP
property (DERR 2018), which is located adjacent to the north of the Site, a background
sample was collected from Riley Elementary School. Riley Elementary School is located
approximately 0.9 miles west of the Site. The reported background arsenic concentration
in this sample was 31.7 mg/kg.
Background arsenic data from the above sites is summarized on Table A-1 (Appendix A). The
location of each of the above sites in relation to the Paxton Site are shown on Figure A-1 (Appendix
A). Geosyntec proposes to use the average arsenic concentration from the above sources of 23.5
mg/kg, as the proposed remediation goal for arsenic at the Site.
The proposed remedial action goals for groundwater are summarized on Table 2 and are based on
the EPA VISLs and DERR ISLs.

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2. REMEDIAL ACTION COMPONENTS
The following subsections describe the measures that will be implemented at the Site to mitigate
the identified impacts and facilitate the planned development activities.
2.1 Building Foundation and Pavement Removal
Building foundations and paved surfaces will be removed via excavation. Concrete and asphalt
will be disposed of as general construction debris. The locations of remaining building foundations
and pavement are shown on Figure 7.
Upon removal of the foundations and pavement, the underlying soil will be visually inspected and
screened with a photoionization detector (PID) by an environmental professional. If impacts are
identified, the impacted soil will be excavated and properly managed at a permitted off-site facility.
Excavation will continue until the impacted soil has been removed based on visual observations
and PID screening results and confirmation samples will be collected from the base and sidewalls
of each excavation (a minimum of one sample from the base and one sample from each side wall).
Samples will be collected in accordance with the sampling procedures (SOP-002) presented in the
Quality Assurance Project Plan (QAPP) (Geosyntec 2024b). Additional opportunistic samples
may be collected based on the judgement of the environmental professional if previously
unencountered impacts are observed or to adequately cover the excavation area, if determined
appropriate. All samples will be analyzed for TPH-DRO/GRO, Oil and Grease, VOCs and RCRA
metals using the analytical methods presented in Section 2.10. If the confirmation samples identify
remaining impacts, additional excavation will be conducted following which additional
confirmation samples will be collected/analyzed.
2.2 Hydraulic Lift Removal
The two hydraulic lifts will be removed via excavation. Hydraulic fluid from the lifts will be
drained and appropriately managed prior to disposal of the lifts. The locations of remaining
building foundations and hydraulic lifts are shown on Figure 7.
Upon removal of the lifts, the underlying soil will be visually inspected and screened with a
photoionization detector (PID) by an environmental professional. If impacts are identified, the
impacted soil will be excavated and properly managed at a permitted off-site facility and waste
manifests will be provided with the Remedial Action Completion Report. Excavation will continue
until the impacted soil has been removed based on visual observations and PID screening results.
It is not currently anticipated that the excavation will extend beyond the water table, but if impacts
are observed below the water table, the environmental professional will consult with the UDEQ
representative regarding the depth at which the excavation should be terminated. It is envisioned
that the excavation could extend below the water table if significant smear zone impacts or
contaminant sources are identified. If impacts are left in place below the water table, it will be
documented in the Remedial Action Completion Report.

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Confirmation samples will be collected following the removal of each lift and any impacted soil
identified during field screening. Confirmation samples will be collected from the base and
sidewalls of each excavation (a minimum of one sample from the base and one sample from each
side wall). Samples will be collected in accordance with the sampling procedures (SOP-002)
presented in the Quality Assurance Project Plan (QAPP) (Geosyntec 2024b). Additional samples
may be collected based on the judgement of the environmental professional to adequately cover
the excavation area, if determined appropriate. All samples will be analyzed for TPH-DRO/GRO,
Oil and Grease, VOCs and RCRA metals using the analytical methods presented in Section 2.10.
If the confirmation samples identify remaining impacts, additional excavation will be conducted
following which additional confirmation samples will be collected/analyzed.
2.3 Shallow Soil Excavation
Excavation will be performed to remove the metals (arsenic, lead and cadmium) and petroleum
hydrocarbon (Oil and Grease and TPH-DRO) related impacts observed in shallow soil within the
Site. This will include excavation in the area shown on Figure 8 to a depth of approximately 12
inches bgs with slightly deeper excavation around locations S-3 and S-6 where deeper impacts
(from 12-18 inches bgs) were identified. Upon removal, all soil will be properly disposed of off-
site. The total excavation area is estimated to be approximately 16,700 square feet and the
excavation volume is estimated to be approximately 800 cubic yards (assuming an expansion
factor of 1.3).
Upon removal of the impacted soil, confirmation samples will be collected from the bottom of the
excavation areas using a grid spacing of approximately 40 feet. During the site characterization,
the vertical extent of impacts was not delineated at three sample locations (e.g., S-3, S-5, S-11,
and S-15). The confirmation samples from the grids where these samples were located will be
biased to be co-located with the prior sample locations. Side wall confirmation samples will also
be collected from the shallow excavation area with an approximate spacing of 60 feet at shown on
Figure 8.
Confirmation samples will be collected in accordance with the sampling procedures presented in
the QAPP for the project (SOP-002). Based on the estimated excavation area, it is anticipated that
a total of approximately 14 bottom and 10 side wall confirmation samples will be collected from
the shallow soil excavation area. The excavation activities will be overseen by an environmental
professional who will also conduct the sampling activities.
The shallow soil excavation confirmation samples will be analyzed for arsenic, lead, cadmium,
TPH-DRO and Oil and Grease, based on the COC identified during the site characterization
activities. All analyses will be performed using the analytical methods presented in Section 2.10.
If the confirmation samples identify that impacts remain, additional excavation will be conducted
following which additional confirmation samples will be collected/analyzed.
It is currently not known whether fill materials will be needed to facilitate Site construction
following the completion of the excavation activities described herein. If needed, clean fill
materials that meet the standards set for the Site will be imported.

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2.4 Subsurface Soil Excavation
The subsurface soil excavation areas are presented on Figure 9. Excavation will be conducted to
remove isolated impacts to subsurface soil identified during previous sampling activities, as
follows:
 MW-3: Impacts in this boring were limited to Oil and Grease which was detected in a soil
sample at a concentration (1,220 mg/kg at a depth of 1 to 2 feet bgs) above the DERR ISL
of 1,000 mg/kg. No other exceedances of the site screening levels were observed at this
location.
At location MW-3, an approximately 5 feet by 5 feet area will be excavated to a depth
approximately 1 foot below the depth where the identified impacts were observed.
 GP-4: An elevated concentration of TCE (2.21 mg/kg) exceeding the residential RSL (0.94
mg/kg) was detected in a subsurface soil sample collected from 6 to 7 feet bgs in boring
GP-4. It is noted that the shallow soil sample collected from this location (0 to 1 feet bgs)
did not show elevated levels of TCE. At location MW-4, an approximately 5 feet by 5 feet
area will be excavated to a depth approximately 1 foot below the depth where the identified
impacts were observed.
 GP-5: An elevated concentration of Oil and Grease was detected at depth of 7 to 8 feet bgs
in the subsurface soil sample collected from GP-5. The reported Oil and Grease
concentration at this depth was 1,360 mg/kg in comparison to the DERR ISL of 1,000
mg/kg. GP-5 is located adjacent to one of the hydraulic lifts that will be removed. Impacted
soil in this area will be addressed in conjunction with the hydraulic lift removal as described
in Section 2.2.
Upon reaching the target depth at each proposed subsurface soil excavation location, the in-place
soil will be screened both visually and with a PID by an environmental professional. If no impacts
are observed the excavation will be terminated and confirmation samples will be collected from
the base of the excavation and sidewalls (a minimum of one sample from the base and one sample
from each side wall). Based on the estimated excavation areas, it is anticipated that a total of five
confirmation samples will be collected from each subsurface soil excavation area. Additional
samples may be collected based on the judgement of the environmental professional to adequately
cover the excavation area, if determined appropriate.
If additional impacts are observed, the excavations will be expanded in stepwise fashion, both
vertically and horizontally, until no indications of visual impacts or elevated PID readings are
observed, prior to collecting the confirmation samples. The excavations will not be extended
beyond the property boundary and potential excavations below the water table will be conducted
in accordance with the approach described in Section 2.2. If impacts are left in place due to the
above conditions, they will be documented in the Remedial Action Completion report. All
impacted soil removed during the excavation activities will be properly managed off-site.

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The subsurface soil excavation confirmation samples will be analyzed for the constituents that
were previously observed to exceed the clean-up goals (Oil and Grease for MW-3 and VOCs for
GP-4) using the analytical methods presented in Section 2.10. If the confirmation samples identify
remaining impacts, additional excavation will be conducted where determined necessary and
additional confirmation samples will be collected and analyzed.
It is currently not known whether fill materials will be needed to facilitate Site construction
following the completion of the excavation activities described herein. If needed, clean fill
materials that meet the standards set for the Site will be imported.
2.5 Petroleum Impacted Groundwater Treatment
Petroleum hydrocarbon (TPH-DRO and/or TPH-GRO) were observed in shallow groundwater in
a localized area within the central portion of the Site (e.g., GP-5, MW-2 and MW-7). The likely
sources of these impacts will be addressed in conjunction with the building foundation and
pavement removal, hydraulic lift removal, shallow soil excavation and subsurface soil excavations
activities and the related confirmation sampling as detailed in Sections 2.1 to 2.4.
As a proactive measure, Oxygen Release Compound (ORC) will also be applied to treat the
localized petroleum hydrocarbons in groundwater at the Site. ORC is designed to increase
dissolved oxygen concentrations and enhance aerobic biodegradation of petroleum
hydrocarbons. Upon contact with groundwater, ORC becomes hydrated and produces a controlled
release of molecular oxygen (10% by weight) for periods of up to 12 months following a single
application. This extended release period allows for sustained aerobic biodegradation while
significantly accelerating the natural attenuation process and improving the efficiency of
petroleum hydrocarbon remediation.
Approximately 150 pounds of ORC will be applied at or below the groundwater table via open
excavations (e.g., excavations associated with removal of the hydraulic lift near GP-5 and
subsurface soil excavation at GP-4) in the central portion of the Site.
Groundwater sampling (utilizing the monitoring wells to be installed following the completion of
Site development/construction activities) will be conducted as described in Section 2.9 to confirm
the effectiveness of the source removal and enhanced groundwater bioremediation activities. If
petroleum hydrocarbon concentrations are observed to exceed cleanup goals during future
groundwater sampling, additional ORC applications or other corrective measures will be
considered as contingency measures following discussion with and approval by UDEQ.
2.6 Potential Unexpected Impacts
If unexpected impacts are identified during implementation of the RAP or other site development
activities, it is envisioned that additional remediation will be conducted using the same general
methodologies described herein following consultation with UDEQ.

Paxton RAP
12
2.7 Vapor Intrusion Mitigation
The Site building will be equipped with a vapor intrusion mitigation system (VIMS) to prevent
potential soil gas migration from the subsurface and prevent human exposure. The proposed VIMS
design is included in Appendix B. The VIMS will consist of vapor barrier and active sub-slab
depressurization (SSD) system beneath the occupied commercial and residential portions of the
ground floor. The VIMS will also be installed beneath the stair wells and elevators that extend to
the ground floor to prevent potential vapor migration through these corridors to upper portions of
the building.
Construction quality assurance (CQA) related inspections will be conducted by Geosyntec during
installation and start-up of the VIMS to help ensure that it is properly installed and operated. As-
built drawings for the completed VIMS system will be provided in the Remedial Action
Completion Report. On-going monitoring will also be conducted following system start-up to
confirm the effectiveness of the VIMS system. Monitoring, operation and maintenance activities,
and contingencies for the VIMS will be described in the Site Management Plan (SMP).
2.8 Monitoring Well Abandonment
The existing on-site monitoring wells will be abandoned to facilitate future construction activities.
The wells will be abandoned in accordance with Utah Administrative Code Section R655-4-14.
Opportunistic groundwater samples may be obtained from the on-site monitoring wells prior to
abandonment. If collected, this data will be utilized to help inform the monitoring well installation
and the groundwater sampling activities outlined in the SMP (see Section 2.9).
2.9 Monitoring Well Installation and Sampling
Three new monitoring wells will be installed at the Site following completion of
development/construction activities to facilitate future groundwater monitoring activities. The
wells will be positioned around the perimeter of the future building in areas where the most
significant groundwater impacts have been observed. The exact locations of the wells will be
finalized following building construction, but approximate locations are shown in Figure 10.
The monitoring wells will be constructed, developed, and sampled in accordance with the Standard
Operating Procedures (SOPs) in the QAPP (Geosyntec 2024b). The wells will be constructed with
2-inch Schedule 40 polyvinyl chloride (PVC) material with approximately 10 feet of well screen,
which will be screened across the water table. At each well, a sand filter pack will be used to
backfill the annular space between the well casing and borehole from total depth to approximately
2 feet above the top of the well screen. Hydrated bentonite chips will be placed above the sand
filter pack to a depth of approximately 1 foot bgs. Wells will be completed at the surface with flush
mounted protective vaults.
The monitoring wells will be sampled using low-flow sampling method and samples will be
analyzed for TPH-GRO/DRO, Oil and Grease, and VOCs (including 1,4-dioxane) using the
methods specified in Section 2.10. The monitoring wells will be sampled using low-flow sampling

Paxton RAP
13
methods. Details regarding the frequency, duration, and evaluation of groundwater sampling
results will be provided in the SMP.
2.10 Laboratory Analytical Methods
All confirmation samples will be submitted to Pace Analytical Laboratory, a National
Environmental Laboratory Accreditation Conference-accredited and Utah-certified analytical
laboratory. Analyses will be completed for the previously identified analytes using the following
EPA approved methods:
 RCRA metals by Method 6010B/7470A/7471A
 TPH-DRO/GRO by Method 8015
 Oil and Grease by Method 1664A/9071
 VOCs by Method 8260B
All analyses will be performed in accordance with method specific requirements and requirements
specified in the QAPP using standard analytical turnaround times. Laboratory reports will include
a Level 3 data package.
2.11 Quality Control Sampling
Quality control samples will include field duplicate, matrix spike/matrix spike duplicate,
equipment blank and trip blank samples (VOCs only). Quality control samples will be collected at
the frequency specified in the QAPP.
2.12 Sample Handling and Custody
Upon collection, all samples will be given a unique identification and will be managed in
accordance with the sample labeling, handling, custody and documentation requirements presented
in the QAPP.
2.13 Sampling Equipment Decontamination
All non-disposable equipment will be decontaminated prior to use and in-between sample
locations in accordance with the procedures specified in the QAPP (SOP-12).

Paxton RAP
14
3. SITE CONTROL MEASURES
The following measures will be conducted during implemented of the activities described herein
to help protect human health and minimize impacts to the environment.
3.1 Health and Safety Plan
A Health and Safety Plan (HASP) will be prepared and implemented to address potential exposure
to site impacts during RAP implementation. All contractors and subcontractors selected to
implement these activities will be responsible for the health and safety of their employees and will
also be required to prepare and implement their own HASP.
3.2 Project Controls
The remediation contractor will be responsible for subsurface clearance, including Blue-Stakes
notification, prior to excavation activities. The contractor will also be responsible for Site security
and the other measures described within this section.
3.3 Remedial Equipment Decontamination
A decontamination area will be designated at the Site to clean remediation equipment (i.e.,
excavators, trucks and other equipment) that comes in contact with impacted soil or other media
prior to leaving the Site. Visible soil and debris will be brushed from the equipment prior to leaving
the Site. Hand tools and other small equipment will also be cleaned before they are removed from
the site.
3.4 Dust Control
The remediation contractor will be required to prepare and implement a dust control plan during
excavation and other potential dust generation activities to prevent potential exposure to impacted
materials. Soil wetting will be the primary control to prevent dust generation. All soil loads leaving
the site will also be tarped or covered. Additional dust control measures that may be implemented,
if determined necessary, include:
 Limiting drop heights when loading soil;
 Stop of work during periods with high winds or other reduced work activities;
 Wetting of stockpiles;
 Other measures, as determined necessary.
3.5 Stormwater Control
A Storm Water Pollution Prevention Plan (SWPP) is not required for the project, as the Site is less
than 1 acre is size. However; contractors will be required to prepare and implement appropriate
Best Management Practices during storm /precipitation events to prevent run-off from the Site. If
excavated materials are stockpiled on-site, appropriate measures (e.g., grading/sloping, berming,

Paxton RAP
15
covering, etc.) will be implemented to minimize potential spreading of impacts. All trucks and
equipment will also be inspected, and cleaned if determined necessary, to prevent tracking of
impacted material from the Site.
3.6 Construction Dewatering
Based on the planned building design, significant construction dewatering is not anticipated. In
limited locations where dewatering is required, all dewatering water will be containerized (e.g.,
using a frac-tank or equivalent) and characterized for management at an off-site disposal facility.
If changes to the above water management strategy are determined to be advantageous (e.g.,
discharge of treated water to the storm sewer or waters of the state are desired), appropriate permits
and approvals will be obtained prior to discharge.
3.7 Public Involvement
A public notice has been prepared to inform the general public and adjacent properties of the
proposed remediation activities. A copy of the notice will be published in the Salt Lake Tribune
and Deseret News and will also be hand-delivered to the adjacent properties. A copy of the public
notice is presented in Appendix C.
3.8 Materials Management
Potential impacted materials generated during the remediation activities will include soil generated
from the shallow surface and subsurface excavation activities and potential excavation of soil
below the building foundations/hydraulic lifts, if determined to be necessary. Additionally,
groundwater may be generated from limited construction dewatering activities in select areas.
These materials will be managed at appropriately permitted off-site facilities. Generated soil and
groundwater will be characterized based on samples collected during the site characterization and
additional samples, if any, required by the disposal facility(ies). Based on available data, it is
assumed that the soil and groundwater will be managed as non-hazardous waste.
The volume of soil and groundwater that is managed during the project will be tracked and waste
manifests will be provided with the Remedial Action Completion Report. Disposal documentation
for hydraulic fluid removed from the lifts will also be included in the Remedial Action Completion
Report.

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16
4. SCHEDULE AND POST REMEDIATION ACTIVITIES
Paxton is prepared to immediately initiate implementation of the RAP and anticipates the
following schedule which would start after completion of the public comment period, resolution
of any comments, and receipt of UDEQ approval:
 Week 1 – Preparation, mobilization, and monitoring well abandonment
 Week 2 – Pavement removal, foundation removal, hydraulic lift removal, and confirmation
sampling
 Week 3 – Soil excavation, confirmation sampling, and ORC application
 Weeks 4 to 5 – Contingency for additional excavation and confirmation sampling (if
determined necessary)
Other components of the RAP (VIMS construction, monitoring well installation and sampling,
etc.) will be contingent on the building schedule. UDEQ will be notified seven days before these
activities are conducted.
Following implementation of the RAP, the following will be conducted:
 Remediation Action Completion Report – This report will be prepared to summarize the
activities conducted and the associated Site observations. It is envisioned that the report
will include the following:
o Site figures;
o Confirmation sample laboratory reports, chain-of-custody forms and validation
reports;
o As-build drawings for the VIMS;
o Photographs documenting the implemented measures; and
o Waste disposal manifests.
 Environmental Covenant - An environmental covenant will be prepared and put in place
to describe the Site impacts and the activity use limitations to prohibit the extraction or use
of groundwater at the Site and reference the Site Management Plan (SMP) that will apply
to the Site. The environmental covenant will be recorded on the chain-of-title for the parcel.
 Site Management Plan – A SMP will be prepared and implemented to help ensure the
continued proper operation and maintenance of the VIMS. The SMP will also describe
future groundwater monitoring activities and include appropriate measures to be
implemented if there are any future subsurface construction or maintenance related
activities.

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17
5. REFERENCES
AGEC. 2023a. Limited Subsurface Sampling Investigation, Tucker Towing, 203 to 225 West
Paxton Avenue, Salt Lake City, Utah. September 2023.
AGEC. 2023b. Limited Subsurface Sampling Investigation No. 2, Tucker Towing, 203 to 225 West
Paxton Avenue, Salt Lake City, Utah. October 2023.
ATLAS. 2023. Phase I Environmental Assessment, Tucker Towing, 215 West Paxton Avenue, Salt
Lake City, Utah. December 2023.
Geosyntec. 2024a. Site Characterization Report, Paxton Development, 203 to 225 West Paxton
Avenue, Salt Lake City, Utah. December 2024 (updated January 30, 2025).
Geosyntec. 2024b. Quality Assurance Project Plan, Paxton Development, 203 to 225 West Paxton
Avenue, Salt Lake City, Utah. June 2024.

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Legend Figure
1
Site Location
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT November 2024
Client LogoPaxton
DevelopmentApproximate Site Boundary
Site
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Legend
Figure
2
Site Location
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT November 2024
Client LogoPaxton
DevelopmentApproximate Site Boundary
Site
Paxton Ave.
W Lucy Ave.
Paxton Place
Apartments
RETEP site
Private Residence
Shop Building
Storage BuildingResidences
Storage
Building
In-ground Lift
Storage Yard
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Legend
Figure
3
Shallow Soil Sample Locations
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT February 2025
Client LogoPaxton
Development
Approximate Site Boundary
Shallow Sample Location (Sample Depths
Shown in Parenthesis)
SS-1 (6-12”,
12-18”)
S-1 (0-6”, 6-
12”, 12-18”)
S-2 (0-6”)
S-4 (0-6”,
12-18”)S-5 (0-6”)
S-6 (0-6”,
12-18”)S-7 (0-6”, 6-
12”, 12-18”)S-8 (0-6”)
S-3 (0-6”, 6-
12”, 12-18”)
S-9 (0-6”)
S-10 (0-6”,
6-12”)
S-14
(0-6”,
6-12”)
S-11 (0-6”)S-12 (0-6”,
6-12”)
S-13 (0-6”)
S-15 (0-6”)
SS-2 (0-6”)
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Legend
Figure
4
Subsurface Soil Sample Locations
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT February 2025
Client LogoPaxton
Development
Approximate Site Boundary
Soil Boring/Monitoring Well Location (Soil
Sample Depths Shown in Parenthesis)
GP-2 (6’-7’)
MW-8
(7’)
MW-4
(7’)
GP-1
(6’-7’)
GP-4 (0’-1’, 6’-7’)
MW-7
(7’)
MW-2 (7’)
MW-3
(1’-2’ )
GP-5
(‘0-1’, 7’-8’ )
MW-6 (7’)
GP-3
(7’-8’)
MW-1 (7’)
MW-10
(7’)
MW-9
(7’)
MW-5 (7’)
Borings Identified with “GP”; Wells
Identified with “MW”
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Legend
Figure
5
Groundwater Sample Locations
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT February 2025
Client LogoPaxton
Development
Approximate Site Boundary
Soil Boring/Monitoring Well Location
GP-2
MW-8 MW-4
GP-1
GP-4
MW-7
MW-2
MW-3
GP-5
MW-6
GP-3
MW-1
MW-10
MW-9
MW-5
Borings Identified with “GP”; Wells
Identified with “MW”
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Legend
Figure
6
Soil Gas Sample Locations
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT December 2024
Client LogoPaxton
DevelopmentApproximate Site Boundary
Soil Gas Vapor Probe
SV-1SV-2
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Legend
Figure
7Salt Lake City, UT November 2024
Client LogoPaxton
Development
Approximate Site Boundary
Approximate Areas With Impervious
Surfaces
Remaining Foundations/Impervious Surfaces and
Hydraulic Lifts
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Approximate Areas with Building
Foundations
Approximate Location of Hydraulic Lifts
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Figure
8
Shallow Soil Excavation Area
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT February 2025
Client LogoPaxton
Development
Approximate Site Boundary
Approximate Shallow Soil Excavation Area
Shallow Sample Location (Sample Depths
Shown in Parenthesis)
SS-1 (6-12”,
12-18”)
S-1 (0-6”, 6-
12”, 12-18”)
S-2 (0-6”)
S-4 (0-6”,
12-18”)S-5 (0-6”)
S-6 (0-6”,
12-18”)
S-7 (0-6”, 6-
12”, 12-18”)S-8 (0-6”)
S-3 (0-6”, 6-
12”, 12-18”)
S-9 (0-6”)
S-10 (0-6”,
6-12”)
S-14
(0-6”,
6-12”)
S-11 (0-6”)S-12 (0-6”,
6-12”)
S-13 (0-6”)
S-15 (0-6”)
SS-2 (0-6”)
Shallow Sample Location with Exceedance of
Cleanup Goal (Sample Depths Shown in
Parenthesis with Exceedances Highlighted)
Approximate Side Wall Confirmation
Sample Location
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Figure
9
Proposed Subsurface Excavation Areas
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT February 2024
Client LogoPaxton
Development
Approximate Site Boundary
Soil Boring/Monitoring Well Location (Soil
Sample Depths Shown in Parenthesis)
GP-2 (6’-7’)
MW-8
(7’)
MW-4
(7’)
GP-1
(6’-7’)
GP-4 (0’-1’, 6’-7’)
MW-7
(7’)
MW-2 (7’)
MW-3
(1’-2’ )
GP-5
(‘0-1’, 7’-8’ )
MW-6 (7’)
GP-3
(7’-8’)
MW-1 (7’)
MW-10
(7’)
MW-9
(7’)
MW-5 (7’)
Soil Boring/Monitoring Well Location with
Cleanup Goal Exceedance (Interval with
exceedance highlighted)
Borings Identified with “GP”; Wells
Identified with “MW”
Proposed Subsurface Excavation Area
Approximately
5’x5’x3’ Deep
Excavation Area
To be
addressed in
conjunction
with hydraulic
lift removal
Approximately
5’x5’x7’ Deep
Excavation Area
> >>>>>>> > > > > > > > > > >> > > > > > > >>
8
6.
7
'
5.
0
'

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5.
7
'
5.
7
'
4.
0
'
Legend
Planned Building Footprint
Proposed Monitoring Well
Location
Well-1
Well-2
Well-3
Figure
10
Approximate Future Monitoring Well Locations
203 to 225 West Paxton Ave.
Salt Lake City, Utah
Salt Lake City, UT February 2024
Paxton
Development
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TABLE 1
SOIL SAMPLE SUMMARY WITH CLEANUP GOALS
PAXTON DEVELOPMENT
SALT LAKE CITY, UTAH
SAMPLE LOCATION
DATE COLLECTED
DEPTH (INCHES)
ANALYTE Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier
ARSENIC 0.68 -23.5 23.5 10.4 12.8 6.92 7.52 15.6 10.7 J 25.9 J 14.3 23.6 34.6 8.48 6.5 4.48 NA 23.3 13.8 11.3
BARIUM 15000 --15000 203 217 NA 111 107 118 J 213 J NA 260 268 NA 75 52.5 NA 374 145 NA
CADMIUM 7.1 --7.1 1.94 2.2 NA 0.891 J+2.49 1.28 J 2.37 J NA 8.79 7.95 1.65 0.609 J+0.681 J+NA 3.1 1.16 NA
CHROMIUM5 85000 --85000 18.8 15.5 NA 11.4 14.4 10.6 16.7 NA 54.2 68.4 NA 9.93 15.1 NA 20.6 11.8 NA
LEAD 200 --200 190 221 53.4 58.9 130 125 J 316 J 224 605 565 186 73.8 385 482 714 270 96.7
SELENIUM 390 --390 1.75 J 1.28 J NA 2.47 1.91 J 0.831 U 0.824 U NA 6.34 J 13.2 J NA 0.774 U 0.778 U NA 2.04 J 0.814 U NA
SILVER 390 --390 0.136 U 0.140 U NA 0.134 U 0.129 U 0.138 U 0.137 U NA 0.131 U 0.653 U NA 0.653 U 0.129 U NA 1.06 U 1.07 U NA
MERCURY 11 --11 0.238 0.318 NA 0.074 0.0548 0.175 0.174 NA 0.173 0.214 NA 0.0474 0.0733 NA 0.638 0.674 NA
TPH-DRO (GC/FID) HIGH FRACTION -500 -500 58.3 J 62 NA 123 52.5 39 48.5 NA 207 J 233 J NA 542 98.9 J NA 1180 118 NA
TPH-GRO (GC/FID) LOW FRACTION -150 -150 6.95 J+3.38 U NA 9.85 2.82 U 3.08 U J 3.36 J+NA 2.37 J 1.81 J NA 0.629 J 1.1 J NA 7.03 3.67 J+NA
OIL & GREASE (HEXANE EXTR)-1000 -1000 852 785 NA 512 251 J 162 150 NA 8270 J 11500 J 345 1440 2070 495 5380 646 NA
BENZENE 1.2 --1.2 0.00713 0.0242 NA 0.0162 0.00169 0.00329 0.00235 NA 0.0163 J 0.00413 J NA 0.00101 J 0.000745 J NA 0.0398 0.0115 NA
N-BUTYLBENZENE 3900 --3900 0.00726 U 0.00739 U NA 0.00612 U 0.00594 U 0.00645 U 0.00665 U NA 0.00631 U 0.00668 U NA 0.00539 U 0.00545 U NA 0.0083 J 0.00711 U NA
SEC-BUTYLBENZENE 7800 --7800 0.00398 U 0.00406 U NA 0.00335 U 0.00326 U 0.00353 U 0.00365 U NA 0.00345 U 0.00366 U NA 0.00296 U 0.00299 U NA 0.0048 J 0.00390 U NA
CARBON TETRACHLORIDE 0.65 --0.65 0.00125 U 0.00127 U NA 0.00105 U 0.00101 U 0.00110 U 0.00114 U NA 0.00168 J 0.00165 J NA 0.000923 U 0.000932 U NA 0.00137 U 0.00122 U NA
CHLOROFORM 0.32 --0.32 0.00143 U 0.00145 U NA 0.00120 U 0.00116 U 0.00126 U 0.00130 U NA 0.00123 U 0.00132 U NA 0.00106 U 0.00107 U NA 0.00157 U 0.00278 J NA
1,1-DICHLOROETHANE 3.6 --3.6 0.000680 U 0.00479 NA 0.00685 0.000555 U 0.000604 U 0.000621 U NA 0.000590 U 0.000826 U NA 0.000505 U 0.000510 U NA 0.000747 U 0.000665 U NA
CIS-1,2-DICHLOROETHENE 63 --63 0.00198 J 0.0294 NA 0.0285 0.000829 U 0.000902 U 0.000928 U NA 0.000881 U 0.000934 U NA 0.000754 U 0.000822 J NA 0.00144 J 0.0127 NA
TRANS-1,2-DICHLOROETHENE 70 --70 0.00144 U 0.00246 J NA 0.00338 J 0.00117 U 0.00128 U 0.00131 U NA 0.00125 U 0.00145 U NA 0.00107 U 0.00108U NA 0.00158 U 0.00141 U NA
ETHYLBENZENE 5.8 --5.8 0.00537 0.0104 NA 0.0186 0.000833 U 0.00786 J 0.00332 J NA 0.0112 J 0.00649 J NA 0.00176 J 0.00208 J NA 0.0267 0.00867 NA
ISOPROPYLBENZENE 1900 --1900 0.00221 J 0.00342 J NA 0.00775 0.000481 U 0.00427 J 0.00186 J NA 0.000511 U 0.00299 J NA 0.00058 J 0.000874 J NA 0.0117 0.00407 NA
P-ISOPROPYLTOLUENE ----0.0131 0.0114 NA 0.00871 0.00289 U 0.0367 J 0.0111 J NA 0.0131 0.0123 NA 0.00262 U 0.0046 J NA 0.07 0.0189 NA
METHYLENE CHLORIDE 57 --57 0.00919 U 0.00934 U NA 0.00774 U 0.00797 J 0.00816 U 0.00840 U NA 0.00797 U 0.0119 J NA 0.00693 J 0.0085 J NA 0.0101 U 0.00900 U NA
4-METHYL-2-PENTANONE (MIBK)33000 --33000 0.00316 U 0.00320 U NA 0.00266 U <0.00258 0.0224 J 0.0114 J NA 0.00274 U 0.00290 U NA 0.00234 U 0.00237 U NA 0.00347 U 0.0175 J NA
METHYL TERT-BUTYL ETHER --0.000485 U 0.000493 U NA 0.000408 U 0.000395 U 0.000431 U 0.000443 U NA 0.000420 U 0.000445 U NA 0.000360 U 0.000363 U NA 0.000533 U 0.000474 U NA
NAPHTHALENE 2 --2 0.0453 J+0.0477 J+NA 0.0382 0.0113 J 0.0302 0.0183 NA 0.0531 0.0459 NA 0.00957 J 0.017 NA 0.104 0.0499 NA
N-PROPYLBENZENE 3800 --3800 0.00294 J 0.00355 J NA 0.00636 0.00108 U 0.00504 J 0.00199 J NA 0.00393 J 0.00280 J NA 0.000976 U 0.00108 J NA 0.0113 0.00492 J NA
STYRENE 6000 --6000 0.000317 U 0.000323 U NA 0.000267 U 0.000259 U 0.000281 U 0.000290 U NA 0.0574 0.0369 NA 0.000235 U 0.000238 U NA 0.000349 U 0.000310 U NA
TETRACHLOROETHENE 24 --24 0.0157 0.0492 NA 0.0246 0.00101 U 0.00110 U 0.00113 U NA 0.0148 0.0122 NA 0.00144 J 0.00501 NA 0.0195 0.0164 NA
TOLUENE 4900 --4900 0.0403 0.0893 NA 0.0921 0.00316 J 0.039 J 0.0153 J NA 0.0718 J 0.0240 J NA 0.00693 0.00568 NA 0.168 0.0534 NA
1,1,1-TRICHLOROETHANE 8100 --8100 0.00128 U 0.00130 U NA 0.00108 U 0.00105 U 0.00113 U 0.00117 U NA 0.00111 U 0.00118 U NA 0.000948 U 0.000958 U NA 0.00140 U 0.00125 U NA
TRICHLOROETHENE 0.94 --0.94 0.015 0.101 NA 0.0477 0.000659 U 0.000717 U 0.000738 U NA 0.00957 0.00850 NA 0.00201 0.0166 NA 0.0205 0.0485 NA
1,2,4-TRIMETHYLBENZENE 300 --300 0.0348 0.0408 NA 0.0784 0.00426 J 0.0536 J 0.0213 J NA 0.0496 0.0312 NA 0.00689 0.0144 NA 0.172 0.0642 NA
1,2,3-TRIMETHYLBENZENE 340 --340 0.0252 0.0287 NA 0.0438 0.00319 J 0.0344 J 0.0173 J NA 0.0313 0.0214 NA 0.00503 J 0.0106 NA 0.12 0.0365 NA
1,3,5-TRIMETHYLBENZENE 270 --270 0.0107 0.011 NA 0.043 0.00226 U 0.0233 J 0.0104 J NA 0.0173 0.0120 NA 0.00325 J 0.00455 J NA 0.0502 0.0243 NA
XYLENES, TOTAL 580 --580 0.0721 0.13 NA 0.22 0.00886 0.0836 J 0.046 J NA 0.12 J 0.0641 J NA 0.0174 0.0244 NA 0.374 0.147 NA
Notes:
All results units are reported as mg/kg
U = Analyte not detected above laboratory method detection limit.
TPH-DRO = Total Petroluem Hydrocarbons - Diesel Range Organics
TPH-GRO = Total Petroluem Hydrocarbons - Gasoline Range Organics
NA = Not Analyzed
Gray highlighted concentrations indicate analyte was detected above laboratory method detection limit
Orange highlighted concentrations exceed Cleanup Goal.
2DERR Initial Screening Level (ISL) for Leaking Underground Storage Tank Sites
5RSL for chromium based on trivalent chromium
*Blind duplicate sample labeled S-30 (6-12)
**Blind duplicate sample labeled S-31 (0-6)
***Blind suplicate sample labeled S-32 (0-6)
Qualifiers (based on final data validation qualification):
1EPA Regional Screening Level (RSL) for Residential Soil, November 2024. RSLs based on cancer
risk of 10-6 and hazard quotient of one.
12-18
09/27/2024
S-1 (12-18)
12-18
09/27/2024
S-4 (12-18)S-3 (12-18)
09/27/2024
12-18
S-3 (6-12)*
07/16/2024
6-12
S-2 (0-6)S-3 (6-12)S-4 (0-6)
0-6Cleanup
Goal4
07/16/2024 07/16/2024
S-6 (12-18)
09/27/2024
12-18
07/16/2024
0-6
S-3 (0-6)
07/16/2024
0-6
S-6 (0-6)
07/16/2024
0-6
S-7 (12-18)
09/27/2024
12-180-6 6-12
S-7 (0-6)S-7 (6-12)
3Background concentration for arsenic based on average background concentration from on-site and nearby background samples as presented in Appendix A.
4Cleanup goal equals background concentration for arsenic and EPA residential RSL or DERR ISL for all other constituents.
UJ: The analyte was not detected above the reported sample quantitation limit. However, the reported quantitation limit is approximate and may or may not represent the actual limit of quantitation necessary to accurately and precisely measure the analyte in the sample.
S-5 (0-6)
6-12 0-6 0-6
07/16/2024 07/16/2024 07/16/202407/16/2024
S-4 (0-6)**S-1 (0-6)
07/16/2024
S-1 (6-12)
07/16/2024
0-6 6-12
U: The analyte was analyzed for, but was not detected above the reported sample quantitation limit.
J: The analyte was positively identified; the associated numerical value is the approximate concentration of the analyte in the sample.
J+: The analyte was positively identified; however, the associated numerical value is likely to be higher than the concentration of the analyte in the sample due to positive bias of associated QC or calibration data or attributable to matrix interference.
EPA RSL1 DERR ISL2 Background3
Page 1 of 2
TABLE 1
SOIL SAMPLE SUMMARY WITH CLEANUP GOALS
PAXTON DEVELOPMENT
SALT LAKE CITY, UTAH
SAMPLE LOCATION
DATE COLLECTED
DEPTH (INCHES)
ANALYTE
ARSENIC 0.68 -23.5
BARIUM 15000 --
CADMIUM 7.1 --
CHROMIUM5 85000 --
LEAD 200 --
SELENIUM 390 --
SILVER 390 --
MERCURY 11 --
TPH-DRO (GC/FID) HIGH FRACTION -500 -
TPH-GRO (GC/FID) LOW FRACTION -150 -
OIL & GREASE (HEXANE EXTR)-1000 -
BENZENE 1.2 --
N-BUTYLBENZENE 3900 --
SEC-BUTYLBENZENE 7800 --
CARBON TETRACHLORIDE 0.65 --
CHLOROFORM 0.32 --
1,1-DICHLOROETHANE 3.6 --
CIS-1,2-DICHLOROETHENE 63 --
TRANS-1,2-DICHLOROETHENE 70 --
ETHYLBENZENE 5.8 --
ISOPROPYLBENZENE 1900 --
P-ISOPROPYLTOLUENE ---
METHYLENE CHLORIDE 57 --
4-METHYL-2-PENTANONE (MIBK)33000 --
METHYL TERT-BUTYL ETHER --
NAPHTHALENE 2 --
N-PROPYLBENZENE 3800 --
STYRENE 6000 --
TETRACHLOROETHENE 24 --
TOLUENE 4900 --
1,1,1-TRICHLOROETHANE 8100 --
TRICHLOROETHENE 0.94 --
1,2,4-TRIMETHYLBENZENE 300 --
1,2,3-TRIMETHYLBENZENE 340 --
1,3,5-TRIMETHYLBENZENE 270 --
XYLENES, TOTAL 580 --
Notes:
All results units are reported as mg/kg
U = Analyte not detected above laboratory method detection limit.
TPH-DRO = Total Petroluem Hydrocarbons - Diesel Range Organics
TPH-GRO = Total Petroluem Hydrocarbons - Gasoline Range Organics
NA = Not Analyzed
Gray highlighted concentrations indicate analyte was detected above laboratory method detection limit
Orange highlighted concentrations exceed Cleanup Goal.
2DERR Initial Screening Level (ISL) for Leaking Underground Storage Tank Sites
5RSL for chromium based on trivalent chromium
*Blind duplicate sample labeled S-30 (6-12)
**Blind duplicate sample labeled S-31 (0-6)
***Blind suplicate sample labeled S-32 (0-6)
Qualifiers (based on final data validation qualification):
1EPA Regional Screening Level (RSL) for Residential Soil, November 2024. RSLs based on cancer
risk of 10-6 and hazard quotient of one.
3Background concentration for arsenic based on average background concentration from on-site and near
4Cleanup goal equals background concentration for arsenic and EPA residential RSL or DERR ISL for al
UJ: The analyte was not detected above the reported sample quantitation limit. However, the reported qua
U: The analyte was analyzed for, but was not detected above the reported sample quantitation limit.
J: The analyte was positively identified; the associated numerical value is the approximate concentration o
J+: The analyte was positively identified; however, the associated numerical value is likely to be higher th
EPA RSL1 DERR ISL2 Background3 Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier
6.5 14.8 15.5 9.25 9.3 12.1 13.6 4.4 4.03 10.9 3.13 26.5 12.4 6.44
70.7 76.3 170 J 88.8 34 103 144 92.2 81.2 137 89.2 251 262 NA
0.909 J+1.35 1.98 0.375 J 0.173 J 1.13 1.38 0.249 J 0.413 J 0.613 0.137 J 1.99 2.5 NA
16.7 11.5 8.16 3.49 67 6.69 8.49 5.65 4.5 7.68 5.2 10.6 17 NA
146 178 183 26.1 6.06 136 190 26.2 27.1 121 12.8 309 414 19.1
0.778 U 1.09 J 0.816 U 0.798 U 0.785 U 0.845 U 0.893 U 0.910 U 0.921 U 0.903 U 0.885 U 0.877 U 1.57 J NA
0.129 U 0.130 U 1.07 U 1.04 U 1.03 U 1.11 U 1.17 U 1.19 U 1.21 U 1.18 U 1.16 U 1.15 U 0.286 J NA
0.0529 0.0848 0.128 0.032 J 0.0212 U 0.195 0.208 0.226 J 0.487 J 0.56 0.0243 J 0.947 0.552 NA
60.4 60 49.8 J 41.6 J 114 39.6 J 126 J 6.92 J 3.17 J 29.7 2.26 J 72.1 143 NA
2.59 U 1.51 J 4.59 J+3.04 U 2.64 U 3.04 U 3.37 U 3.51 U 3.56 U 3.7 U 3.58 U 4.76 J+3.36 U NA
362 445 785 J 646 2280 1250 979 116 J 120 J-128 38.2 U 184 1220 151
0.00713 0.00169 0.035 0.000911 J 0.000493 U 0.00153 0.0155 0.000655 U 0.000666 U 0.00671 0.000670 U 0.0184 0.000911 J NA
0.00544 U <0.00565 0.00669 U 0.00638 U 0.00555 U 0.00639 U 0.00708 U 0.00736 U 0.00748 U 0.00779 U 0.00753 U 0.00728 U 0.00705 U NA
0.00298 U 0.0042 J 0.00367 U 0.00350 U 0.00304 U 0.00351 U 0.00389 U 0.00404 U 0.00411 U 0.00427 U 0.00413 U 0.00399 U 0.00387 U NA
0.000930 U 0.000966 U 0.00114 U 0.00110 U 0.000949 U 0.00109 U 0.00121 U 0.00126 U 0.00128 U 0.00174 J 0.00129 U 0.00125 U 0.00121 U NA
0.00107 U 0.00111 U 0.00131 U 0.00125 U 0.00109 U 0.00125 U 0.00139 U 0.00144 U 0.00147 U 0.00152 U 0.00147 U 0.00143 U 0.00138 U NA
0.000509 U 0.000529 U 0.0106 0.000596 U 0.000519 U 0.0033 0.00951 0.000689 U 0.000700 U 0.0023 J 0.000704 U 0.000681 U 0.00297 J NA
0.000760 U 0.000790 U 0.165 0.0101 0.000775 U 0.0321 0.0606 0.00103 U 0.00105 U 0.0114 0.00105 U 0.00102 U 0.0106 NA
0.00108 U 0.00112 U 0.00733 0.00126 U 0.00110 U 0.00477 J 0.0066 J 0.00146 U 0.00148 U 0.00167 J 0.00149 U 0.00144 U 0.00185 J NA
0.00521 0.00312 0.00988 0.000894 U 0.000778 U 0.00196 J 0.00704 0.00103 U 0.00143 J 0.00341 J 0.00172 J 0.0289 0.00277 J NA
0.00195 J 0.00199 J 0.00277 J 0.000516 U 0.000449 U 0.00122 J 0.00152 J 0.000596 U 0.000606 U 0.000630 U 0.000610 U 0.00434 0.00215 J NA
0.01 0.0132 0.0132 0.00310 U 0.00269 U 0.00679 0.00761 0.00358 U 0.00405 J 0.00508 J 0.00366 U 0.0203 0.00765 NA
0.00688 U 0.00828 J 0.0319 U 0.0304 U 0.00701 U 0.0304 U 0.0337 U 0.00931 U 0.0356 U 0.00983 U 0.00951 U 0.0347 U 0.00891 U NA
0.0172 J 0.00734 J 0.0133 J 0.00276 U 0.00241 U 0.00309 J 0.00308 U 0.00320 U 0.00325 U 0.00338 U 0.00327 U 0.00946 J 0.00306 U NA
0.000363 U 0.000377U 0.000447 U 0.000425 U 0.00086 J 0.000426 U 0.000472 U 0.000491 U 0.000499 U 0.000519 U 0.000502 U 0.00125 J 0.000470 U NA
0.0248 0.0118 J 0.0451 0.00593 U 0.00879 J 0.0192 0.0225 0.00685 U 0.00696 U 0.0143 J 0.00700 U 0.0203 0.0315 J+NA
0.00215 J 0.00328 J 0.00293 J 0.00115 U 0.00100 U 0.00136 J 0.00219 J 0.00133 U 0.00135 U 0.00141 U 0.00137 U 0.00981 0.00189 J NA
0.000237 U 0.000246 U 0.000292 U 0.000278 U 0.000242 U 0.000279 U 0.000309 U 0.000321 U 0.000326 U 0.000339 U 0.000328 U 0.000317 U 0.000307 U NA
0.000928 U 0.000964 U 0.0461 0.00388 0.000946 U 0.00425 0.0112 0.00243 J 0.0017 J 0.119 0.0128 1.71 0.209 NA
0.0352 0.0168 0.169 J 0.00459 J 0.00137 U 0.0115 0.0781 0.00182 U 0.00185 U 0.0264 0.00186 U 0.176 0.00976 NA
0.000956 U 0.000993 U 0.00564 0.00112 U 0.000975 U 0.00145 J 0.00125 U 0.00129 U 0.00132 U 0.016 0.00133 U 0.00604 0.0148 NA
0.000605 U 0.000629 U 0.0625 0.0031 0.000617 U 0.0106 0.0258 0.000819 U 0.000832 U 0.244 0.0159 0.0103 0.176 NA
0.031 0.175 0.0529 0.00276 J 0.00167 U 0.019 0.02 0.00222 U 0.00225 U 0.00455 J 0.00227 U 0.119 0.0273 NA
0.0223 0.159 0.0379 0.00236 J 0.00167 U 0.0109 0.00954 0.00222 U 0.00225 U 0.00319 J 0.00227 U 0.0462 0.0165 NA
0.00951 0.0402 0.0132 0.00243 U 0.00211 U 0.00772 0.00609 J 0.00281 U 0.00285 U 0.00296 U 0.00287 U 0.0533 0.0104 NA
0.0805 0.053 0.142 0.00571 J 0.000930 U 0.0311 0.0793 0.00123 U 0.00235 J 0.0214 0.00244 J 0.326 0.0456 NA
SS-1 (12-18)
09/30/2024
12-18
S-15 (0-6)SS-1 (6-12)
0-6 0-6 6-12 0-6
09/30/2024 09/27/2024 07/16/2024
S-12 (0-6)
6-12 0-6 6-120-6 6-12 0-6 0-60-6 0-6
S-12 (6-12)S-13 (0-6)S-13 (0-6)***S-14 (0-6)
09/27/2024 09/27/2024 09/30/2024 09/30/2024 09/30/2024
S-10 (0-6)S-10 (6-12)S-11 (0-6)
07/16/2024 07/16/2024 09/27/2024 09/27/2024 09/30/2024
S-14 (6-12)S-8 (0-6)S-9 (0-6)
Page 2 of 2
TABLE 2
GROUNDWATER SAMPLE SUMMARY WITH CLEANUP GOALS
PAXTON DEVELOPMENT
SALT LAKE CITY, UTAH
SAMPLE LOCATION
DATE COLLECTED
Analyte Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier Result Qualifier
OIL & GREASE (HEXANE EXTR)--10 -10 1.29 U J 1.68 J 1.22 U 1.38 U 1.36 U 1.36 U 1.22 U 1.38 U 1.36 U 1.36 U
TPH-DRO (GC/FID) HIGH FRACTION --1 -1 0.107 0.0391 J 1.08 0.134 0.133 0.145 0.13 0.189 0.164 J-0.216
TPH-GRO (GC/FID) LOW FRACTION --1 -1 0.1 U 0.1 U 0.139 J 0.1 U 0.254 J+0.570 3.28 0.583 0.1 U 0.1 U
BENZENE 0.005 --0.00159 0.00159 0.0000941 U 0.0000941 U 0.000232 J 0.0014 0.000247 J 0.000343 J 0.00141 0.000292 J 0.0000941 U 0.0000941 U R
1,1-DICHLOROETHANE -0.0028 -0.00764 0.00764 0.000100 U 0.000100 U 0.00965 0.00405 0.0437 0.0829 0.707 0.138 0.000100 U 0.000100 U R
1,2-DICHLOROETHANE 0.005 --0.00224 0.00224 0.0000819 U 0.0000819 U 0.0000819 U 0.0000819 U 0.0000819 U 0.0000819 U 0.00114 0.0000819 U 0.0000819 U 0.0000819 U R
1,1-DICHLOROETHENE 0.007 --0.00387 0.00387 0.000188 U 0.000188 U 0.00284 0.000683 J 0.00647 0.0233 0.141 0.0416 0.000188 U 0.000188 U R
CIS-1,2-DICHLOROETHENE 0.07 --0.250 0.250 0.000126 U 0.000126 U 0.146 0.0527 0.247 0.672 4.19 0.726 0.000309 J 0.000166 J
TRANS-1,2-DICHLOROETHENE 0.1 --0.109 0.109 0.000149 U 0.000149 U 0.00346 0.00162 0.00881 0.0195 0.0901 0.0127 0.000149 U 0.000149 U R
1,2-DICHLOROPROPANE 0.005 --0.00658 0.00658 0.000149 U 0.000149 U 0.000149 U 0.000149 U 0.000149 U 0.000255 J 0.00695 0.000149 U 0.000149 U 0.000149 U R
ETHYLBENZENE 0.7 --0.00349 0.00349 0.000137 U 0.000137 U 0.000137 U 0.000175 J 0.000137 U 0.000137 U 0.000137 U 0.000137 U 0.000137 U 0.000137 U R
TETRACHLOROETHENE 0.005 --0.0149 0.0149 0.000300 U 0.000300 U 0.000300 U 0.000401 J 0.000300 U 0.000300 U 0.000300 U 0.000300 U 0.000300 U 0.000300 U R
TOLUENE 1 --19.2 19.2 0.000278 U 0.000278 U 0.000278 U 0.00123 0.000278 U 0.000278 U 0.000278 U 0.000278 U 0.000278 U 0.000278 U R
1,1,1-TRICHLOROETHANE 0.2 --7.420 7.420 0.000149 U 0.000149 U 0.000149 U 0.000163 J 0.000149 U 0.000149 U 0.000149 U 0.000149 U 0.000149 U 0.000149 U R
TRICHLOROETHENE 0.005 --0.0019 0.0019 0.000190 U 0.000190 U 0.00034 J 0.00162 0.00112 0.00115 0.00141 0.000632 J 0.000190 U 0.000190 U R
VINYL CHLORIDE 0.002 --0.000147 0.000147 0.000234 U 0.000234 U 0.00191 0.000865 J 0.0434 0.00767 0.28 0.0105 0.000234 U 0.000234 U R
XYLENES, TOTAL 10 --0.385 0.385 0.000174 U 0.000174 U 0.000174 U 0.000433 J 0.000174 U 0.000174 U 0.000174 U 0.000174 U 0.000174 U 0.000174 U R
Notes:
All results units are reported as mg/l
U = Analyte not detected above laboratory method detection limit.
Gray highlighted concentrations indicate analyte was detected above laboratory method detection limit
Orange highlighted concentrations exceed EPA MCLs, RSLs or DERR ISLs. RSLs only applied if MCL does not exist for a parameter
Underlined and bold concentrations exceed EPA VISLs
U = Analyte not detected. Value shown is the method detection limit.
TPH-DRO = Total Petroluem Hydrocarbons - Diesel Range Organics
TPH-GRO = Total Petroluem Hydrocarbons - Gasoline Range Organics
EPA MCL = EPA Maximum Containment Level (MCL) for drinking water
EPA RSL = EPA Regional Screening Level (RSL) for Tap Water, November 2024. RSLs based on residential exposure using cancer risk of 10-6 and hazard quotient of one.
EPA VISL = EPA Vapor Intrusion Screening Level (VISL). VISL based on residential exposure using cancer risk of 10-6 and hazard quotient of one.
DERR ISL = Division of Environmental Response and Remediation Initial Screening Levels
*Blind duplicate sample labeled MW-25
Qualifiers (based on final data validation qualification):
MW-2
07/17/2024
MW-1 MW-10MW-4 MW-7MW-3 MW-9
07/18/2024
MW-1*
07/17/2024 07/17/2024
MW-5
07/18/2024
MW-8
R-: The sample results are rejected due to deficiencies in the ability to analyze the sample and meet quality control criteria. The presence or absence of the analyte cannot be verified.
07/17/2024 07/17/2024 07/18/2024 07/18/202407/17/2024
Petroleum Hydrocarbons
Volatile Orgainic Compounds
J+: The analyte was positively identified; however, the associated numerical value is likely to be higher than the concentration of the analyte in the sample due to positive bias of associated QC or calibration data or attributable to matrix interference.
J: The analyte was positively identified; the associated numerical value is the approximate concentration of the analyte in the sample.
UJ: The analyte was not detected above the reported sample quantitation limit. However, the reported quantitation limit is approximate and may or may not represent the actual limit of quantitation necessary to accurately and precisely measure the analyte in the sample.
EPA MCLs EPA RSL DERR ISL EPA VISLs Cleanup Goal
1

Paxton RAP

APPENDIX A
ARSENIC BACKGROUND DATA

J.

W
e
l
c
h
Figure
A-1Salt Lake City, UT February 2025
Client LogoPaxton
Development
Site
VCP #C125
VCP #C108
VCP #C109
VCP #C103
0.75 Miles
Surrounding Background
Arsenic Locations
RETEP
Background sample location
for RETEP (Riley
Elementary)
Table A-1
Summary of Arsenic Background Levels for the Site and Surrounding Properties
Site Name Site Address Site Reference Source Arsenic Background Concentration
(mg/kg)
Paxton Site 203 to 225 West Paxton Avenue VCP Site C-129
Average concentration from sample location (S-
10) in residential area (northwest corner) of the
Paxton Property
11.7
Liberty Corner 300 West and 1300 South VCP Site C-125 Established background cleanup level in
approved RAP 13.6
Bumper House
and Chrome Works
255, 259, and 269 Brooklyn Avenue VCP Site C-103 Established background cleanup level in
approved RAP 22.1
Union Pacific
Provo Line
1000 West 500 South VCP Site C-108 Established background cleanup level in
approved RAP 35
Trillium Flow
Technologies
Approximately 700 South and
Woodbine Street VCP Site C-109 Established background cleanup level in
approved RAP 27
RETEP 216 West Paxton Avenue CERLIS Site Background sample collected from Riley
ElementaryA 31.7
23.5
Notes:
All concentrations reported in mg/kg
ARiley Elementary is located approximately 0.9 miles west of the Paxton Site at 1410 South 800 West
Average

Paxton RAP

APPENDIX B
PROPOSED VIMS DESIGN

© 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TomTom
PREPARED FOR:
VICINITY MAP
1" = 5 MILES
N LOCATION MAP
SOURCE: © 2024 MICROSOFT BING MAPS
1" = 400'
KNIGHTON ARCHITECTURE
55 N UNIVERSITY AVE SUITE 227
PROVO, UT 84601
SITE
N
SOURCE: © 2024 MICROSOFT BING MAPS
VAPOR INTRUSION MITIGATION SYSTEM DESIGN
THE PAXTON
203 PAXTON AVENUE
SALT LAKE CITY, UTAH
FEBRUARY 2025
DETAIL IDENTIFICATION LEGEND
ENGINEER OF RECORD:
BRENT ROBINSON
215 SOUTH STATE STREET SUITE 500
SALT LAKE CITY, UT 84111
[e-mail]
801-853-8185
UT P.E. LICENSE NO. 189975-2202
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SALT LAKE CITY, UTAH
PROJECT:
SITE:
TITLE:
APPROVED BY:
REVIEWED BY:DRAWING NO.:
OF
DRAWN BY:
DESIGN BY:
CHECKED BY:FILE:
PROJECT NO.:
DATE:NOVEMBER 2024
SLC1091.01
6
DATEREV APPDESCRIPTIONDRN
THIS DRAWING MAY NOT BE ISSUED
FOR PROJECT TENDER OR
CONSTRUCTION, UNLESS SEALED.
SIGNATURE
DATEDESIGN DRAWING - NOT FOR CONSTRUCTION
NOV-2024A BRVIMS DESIGN SDB
JN
SDB
JN
EL
BR
Geosyntec Consultants, Inc.
VA License No. 0411001425
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
KEPHART
2555 WALNUT STREET
DENVER, COLORADO
SLC1091.01-C001
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COVER SHEET
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DRAWING LIST
NUMBER TITLE
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2 GENERAL NOTES
3 VIMS PLAN
4 DETAILS I
5 DETAILS II
6 DETAILS III
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SALT LAKE CITY, UTAH
PROJECT:
SITE:
TITLE:
APPROVED BY:
REVIEWED BY:DRAWING NO.:
OF
DRAWN BY:
DESIGN BY:
CHECKED BY:FILE:
PROJECT NO.:
DATE:NOVEMBER 2024
SLC1091.01
6
DATEREV APPDESCRIPTIONDRN
THIS DRAWING MAY NOT BE ISSUED
FOR PROJECT TENDER OR
CONSTRUCTION, UNLESS SEALED.
SIGNATURE
DATEDESIGN DRAWING - NOT FOR CONSTRUCTION
NOV-2024A BRVIMS DESIGN SDB
JN
SDB
JN
EL
BR
Geosyntec Consultants, Inc.
VA License No. 0411001425
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
KEPHART
2555 WALNUT STREET
DENVER, COLORADO
SLC1091.01-C002
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FEB-2025B BRUDEQ COMMENT REVISION SDB
GENERAL NOTES
2
ER-01
MP-01
TS-01
MP-03
MP-02
ER-02
MP-06 MP-05
MP-04
ER-03
VIMS LEGEND
EXTRACTION RISER (ER) PIPING LOCATION
SUBSLAB PERFORATED 3" SCH 40 PVC EXTRACTION PIPING
SUBSLAB SOLID 3" SCH 40 PVC EXTRACTION PIPING
UNCAPPED 3" SCH 40 PVC EXTRACTION PIPING END
SUBSLAB SOLID 3" SCH 40 PVC TRANSFER PIPING
AREA OF VENTING AGGREGATE AND VAPOR BARRIER MEMBRANE
TYPICAL MONITORING POINT VAPOR PIN LOCATION
SUBSLAB SOLID 2" SCH 40 PVC MP CONDUIT
TYPICAL MONITORING POINT SUBSLAB PROBE
SOLID 1" SCH 40 PVC TELEMETRY SYSTEM CONDUIT
SYSTEM MONITOR
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1 2 3
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54 6 7 8
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VAPOR INTRUSION MITIGATION SYSTEM DESIGN
SALT LAKE CITY, UTAH
PROJECT:
SITE:
TITLE:
APPROVED BY:
REVIEWED BY:DRAWING NO.:
OF
DRAWN BY:
DESIGN BY:
CHECKED BY:FILE:
PROJECT NO.:
DATE:NOVEMBER 2024
SLC1091.01
6
DATEREV APPDESCRIPTIONDRN
THIS DRAWING MAY NOT BE ISSUED
FOR PROJECT TENDER OR
CONSTRUCTION, UNLESS SEALED.
SIGNATURE
DATEDESIGN DRAWING - NOT FOR CONSTRUCTION
NOV-2024A BRVIMS DESIGN SDB
JN
SDB
JN
EL
BR
Geosyntec Consultants, Inc.
VA License No. 0411001425
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
KEPHART
2555 WALNUT STREET
DENVER, COLORADO
SLC1091.01-C003
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FEB-2025B BRUDEQ COMMENT REVISION SDB
NOTES:
1.TEMPORARY RISER PIPE STUB OF AT LEAST 18-INCHES ABOVE THE FINISHED FLOOR REQUIRED TO CONDUCT
POST-CONSTRUCTION / VACUUM TESTS. UPON COMPLETION OF VACUUM TESTS, THE REMAINDER OF THE
RISER PIPING SECTIONS TO BE INSTALLED.
2.SEAL VAPOR BARRIER MEMBRANE PER MANUFACTURER'S RECOMMENDATIONS TO ADHERE TO ENTIRE
CONCRETE FOOTING AROUND COLUMN INCLUDING LOCATIONS WITHOUT RISER PIPES.
3.URETHANE CAULK SHALL BE APPLIED PER THE MANUFACTURER'S RECOMMENDATIONS TO RISER PIPE AND
CONDUIT PENETRATIONS TO SEAL AGAINST AIR LEAKS.
N
0 10 20
SCALE IN FEET
FOOTING AND FOUNDATION VIMS PLAN
VIMS PLAN
3
TYPICAL MONITORING POINT
VAPOR PIN LOCATION
7
4
EXTRACTION PIPE RUN BETWEEN
STAIRWELLS TO BE SLOPED TO
ALLOW CONDENSATE TO DRAIN
TO AN EXTRACTION POINT
TYPICAL VIM DETAIL
1
4
TYPICAL VIMS AT EXTERIOR
WALL AT CONCRETE COLUMN
5
4
TYPICAL VIMS AT
FOOTING AT RAMP WALL
4
4
TYPICAL VIMS AT
EXTERIOR FOOTING
3
4
TYPICAL EXTRACTION RISER PIPE
THROUGH CONCRETE PAD AND
TYPICAL EXTRACTION RISER PIPE
THROUGH BUILDING
9
5
10
5
SYSTEM MONITOR
12
5
TYPICAL VIMS AT
INTERIOR FOOTING
2
4
TYPICAL MONITORING
POINT SUBSLAB PROBE
6
4 TYPICAL EXTRACTION
PIPING THROUGH TRENCH
8
5
TYPICAL EXTRACTION
PIPING THROUGH TRENCH
8
5 TYPICAL EXTRACTION
PIPING THROUGH TRENCH
8
5
TYPICAL MONITORING POINT
VAPOR PIN LOCATION
7
4
TYPICAL VIMS AT
INTERIOR FOOTING
2
4
TYPICAL VIMS AT INTERIOR
FOOTING
2
4
TYPICAL VIMS AT INTERIOR
FOOTING
2
4
TYPICAL EXTRACTION
PIPING THROUGH TRENCH
8
5
10' LENGTH
PERFORATED
PIPE END
10' LENGTH
PERFORATED
PIPE END
10' LENGTH
PERFORATED
PIPE END
CONCRETE SLAB (BY OTHERS)
NON-WOVEN CUSHION GEOTEXTILE
MEMBRANE
NON-WOVEN CUSHION GEOTEXTILE
4" VENTING AGGREGATE
NON-WOVEN FILTER GEOTEXTILE
SUBGRADE (BY OTHERS)
NOTE:
1.THE EPRO EV40 GEOMEMBRANE, OR AN ENGINEER APPROVED EQUAL,
IS SPECIFIED AND REFEREED TO HEREIN AS THE "MEMBRANE". THE
EV40 MEMBRANE IS A COMPOSITE MEMBRANE WITH A CUSHION
GEOTEXTILE BONDED TO THE BASE OF THE MEMBRANE. AN
ADDITIONAL CUSHION GEOTEXTILE IS NOT REQUIRED BETWEEN THE
VENTING AGGREGATE AND MEMBRANE IF EPRO EV40 IS USED. REFER
TO THE GENERAL NOTES FOR ADDITIONAL DETAIL.
6' MIN
TYPICAL VIM DETAIL
SEAL WITH POLYURETHANE CAULK
1
4
6' MIN
SEAL WITH POLYURETHANE CAULK
TYPICAL VIM DETAIL
1
4
TYPICAL VIM DETAIL6' MIN
SEAL WITH POLYURETHANE CAULK
1
4
CONCRETE SLAB (BY OTHERS)
SUBGRADE (BY OTHERS)
LOCKABLE ACCESS PANEL
1/4" COMPRESSION FITTING
BALL VALVE
INTERIOR WALL
6" STAINLESS STEEL IMPLANT
(ESP PART# SVPT96-6PR OR
ENGINEER APPROVED
EQUIVALENT)
BALL VALVE
CONDUIT SEALED WITH POLYURETHANE CAULK
CONDUIT SEALED WITH POLYURETHANE CAULK
2" SCH 40 (MIN) PVC
2" SCH 40 PVC TEE WITH THREADED PLUG
NOTES:
1.SEAL PIPE PENETRATION THROUGH MEMBRANE IN ACCORDANCE WITH CONSTRUCTION
DOCUMENTS AND MANUFACTURER REQUIREMENTS.
2.THREADED FITTINGS SHALL BE USED TO CONSTRUCT THE 2" SCH 40 PROTECTIVE PIPE
CONDUIT. PVC PRIMER AND CEMENT SHALL NOT BE USED.
VENTING AGGREGATE PER PLAN
ANCHOR TO WALL STUD (TYP)
TYPICAL VIM DETAIL
6' MIN
SEAL WITH POLYURETHANE CAULK
1
4
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1 2 3
4 5 6 7 8
54 6 7 8
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VAPOR INTRUSION MITIGATION SYSTEM DESIGN
SALT LAKE CITY, UTAH
PROJECT:
SITE:
TITLE:
APPROVED BY:
REVIEWED BY:DRAWING NO.:
OF
DRAWN BY:
DESIGN BY:
CHECKED BY:FILE:
PROJECT NO.:
DATE:NOVEMBER 2024
SLC1091.01
6
DATEREV APPDESCRIPTIONDRN
THIS DRAWING MAY NOT BE ISSUED
FOR PROJECT TENDER OR
CONSTRUCTION, UNLESS SEALED.
SIGNATURE
DATEDESIGN DRAWING - NOT FOR CONSTRUCTION
NOV-2024A BRVIMS DESIGN SDB
JN
SDB
JN
EL
BR
Geosyntec Consultants, Inc.
VA License No. 0411001425
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
KEPHART
2555 WALNUT STREET
DENVER, COLORADO
SLC1091.01-C004
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FEB-2025B BRUDEQ COMMENT REVISION SDB
1
SCALE: NOT TO SCALE
DETAIL
TYPICAL VIM DETAIL3
2
SCALE: NOT TO SCALE
DETAIL
TYPICAL VIMS AT INTERIOR FOOTING3
3
SCALE: NOT TO SCALE
DETAIL
TYPICAL VIMS AT EXTERIOR FOOTING3
5
SCALE: NOT TO SCALE
DETAIL
TYPICAL VIMS AT EXTERIOR WALL AT CONCRETE COLUMN3
6
SCALE: 1" = 1'
DETAIL
TYPICAL MONITORING POINT SUBSLAB PROBE3
DETAILS I
4
4
SCALE: NOT TO SCALE
DETAIL
TYPICAL VIMS AT FOOTING AT RAMP WALL3
7
SCALE: 1" = 1'
DETAIL
TYPICAL MONITORING POINT VAPOR PIN LOCATION3
CONCRETE SLAB (BY OTHERS)
NON-WOVEN CUSHION GEOTEXTILE
GEOMEMBRANE VAPOR BARRIER
NON-WOVEN CUSHION GEOTEXTILE
4" VENTING AGGREGATE
NON-WOVEN FILTER GEOTEXTILE
SUBGRADE (BY
OTHERS)
3" SCH 40 PVC PIPE
10"
12"
1" MIN / 2" MAX
NON-WOVEN FILTER GEOTEXTILE
VENTING AGGREGATE
3" MIN
CONCRETE SLAB (BY OTHERS)
NOTE:
1.ROUTE PIPE TO MINIMIZE LENGTH OF PIPE RUNS AND NUMBER OF
FITTINGS. ROOF PENETRATION SHOULD BE COORDINATED WITH
ARCHITECT AND SHOULD MEET EXHAUST REQUIREMENTS PER SHEET 2.
COLUMN OR STUD
WALL (BY OTHERS)PIPE LABEL (TYP)
FIRE STOP PROTECTION BETWEEN FLOORS
ACCORDING TO BUILDING CODE (TYP)
4" Ø SCH 40 SOLID WALL PVC AIR EXTRACTION PIPE
HANG OR OTHERWISE SUPPORT VIMS
HORIZONTAL PIPING ROOF JOIST AS
APPROVED BY STRUCTURAL ENGINEER (TYP)
SLOPE TO DRAIN
ROOF PIPE BOOT
PER BUILDING CODE
3/8" MONITORING PORT (THREADED AND PLUGGED)
(ACCESS PANEL TO BE INSTALLED FOR ACCESS TO
MONITORING PORT AND TUBING CONNECTON)
MONITORING TUBING (1/4" REINFORCED POLYETHYLENE)
ATTACHED TO BARB FITTING IN PVC EXTRACTION RISER
PIPE AND EXTENDED TO SYSTEM MONITOR (DETAIL 12)
9
5
TYPICAL EXTRACTION
RISER PIPE THROUGH
CONCRETE PAD
11
5
TO TYPICAL
EXTRACTION VENT
WITH ACTIVE FAN
3" TO 4" Ø SCH 40 PVC REDUCER
PIPE BRACKET TO WALL (TYP)
TYPICAL VIM DETAIL
3" DIA SCH. 40 PVC PIPE, LAY FLAT WITH
5/8" DIAMETER DRAIN HOLES POINTING
DOWN ON 3" CENTERS THAT EXTEND 3
FEET BEYOND EDGE OF FOOTING
1
4
14" VENTING AGGREGATE
VAPOR BARRIER MEMBRANE TO BE BOOTED
TO PIPE PER VAPOR BARRIER MEMBRANE
MANUFACTURER'S RECOMMENDATIONS
SEAL VAPOR BARRIER MEMBRANE TO FOOTING 6"
(MIN.) PER MANUFACTURER'S RECOMMENDATIONS
SEAL WITH URETHANE CAULK
4" TO 3" SCH 40 PVC REDUCER
FAN (TO BE SPECIFIED
PENDING PILOT TESTING)
PROVIDE 120V AND 20 AMP
POWER WITHIN 5' OF FAN
FOR CONTINGENT ACTIVE
OPERATION
WEATHER TIGHT
HOUSING WITH SHUT
OFF SWITCH
STEEL
CLAMPS
UNISTRUT
EXHAUST PIPE
1/2" BIRD SCREEN ON EXHAUST
MINIMUM 15' HORIZONTALLY TO ANY HVAC
ROOF-TOP-UNIT (RTU) OR OPENING INTO
BUILDING. MINIMUM 10' TO ANY WALL
INCLUDING PARAPET (ALL DIRECTIONS)
1/2" NPT BRASS SAMPLE
PORT BALL VALVE
ROOF BOOT (TYP)
ELECTRICAL
CONDUIT
CONDENSATE COLLAR
LOCATED INSIDE FAN BOX
10
5
TYPICAL EXTRACTION
RISER PIPE THROUGH
BUILDING
EXTERIOR WALL
SEAL AROUND UTILITY PENETRATION
FOOTING
6"
6"
2'-0"6"
EXTERIOR WALL
PIPE BEDDING MATERIAL, BY OTHERS
SEAL AROUND UTILITY PENETRATIONS
INCOMING UTILITY
INCOMING UTILITY
6"
BOOT PIPE TO VAPOR BARRIER MEMBRANE
BOOT PIPE TO VAPOR BARRIER MEMBRANE
PLAN
SECTION
6"
6"
2'-0"
ZONE OF SAND MIXED WITH CEMENT
AND BENTONITE (4:1:1 PORTIONS)
PROPOSED GRADE
NOTE:
1.DETAIL IS FOR DIAGRAMMATIC
PURPOSES. ALL UTILITIES ENTERING
INTO THE SUB-SLAB VIMS AREA REQUIRE
TRENCH DAM ON EXTERIOR AND (IF
APPLICABLE) AN INTERIOR BOOT
THROUGH FOUNDATION PENETRATIONS
SOIL BACKFILLZONE OF SAND MIXED WITH CEMENT
AND BENTONITE (4:1:1 PORTIONS)
PROVIDE 120V AC, 15 AMP SERVICE WITHIN 5'-0" OF
RADONAWAY CHECKPOINT IIA MONITOR
RADONAWAY CHECKPOINT IIA
(RADONAWAY #28001-2) (TYP)
TO EXTRACTION RISER PIPING
ER-01 ER-02
NOTE:
MOUNT SYSTEM MONITOR 5 FEET ABOVE FINISHED FLOOR ON AN
APPROPRIATELY SIZED SHEET OF 3/4 INCH PLYWOOD PAINTED WHITE.
ER-03
DWYER MAGNEHELIC GAUGE (TYP)
1/4" INSIDE DIA.
TUBING
F
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1 2 3
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54 6 7 8
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VAPOR INTRUSION MITIGATION SYSTEM DESIGN
SALT LAKE CITY, UTAH
PROJECT:
SITE:
TITLE:
APPROVED BY:
REVIEWED BY:DRAWING NO.:
OF
DRAWN BY:
DESIGN BY:
CHECKED BY:FILE:
PROJECT NO.:
DATE:NOVEMBER 2024
SLC1091.01
6
DATEREV APPDESCRIPTIONDRN
THIS DRAWING MAY NOT BE ISSUED
FOR PROJECT TENDER OR
CONSTRUCTION, UNLESS SEALED.
SIGNATURE
DATEDESIGN DRAWING - NOT FOR CONSTRUCTION
NOV-2024A BRVIMS DESIGN SDB
JN
SDB
JN
EL
BR
Geosyntec Consultants, Inc.
VA License No. 0411001425
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
KEPHART
2555 WALNUT STREET
DENVER, COLORADO
SLC1091.01-C005
C:
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FEB-2025B BRUDEQ COMMENT REVISION SDB
8
SCALE: NOT TO SCALE
DETAIL
TYPICAL EXTRACTION PIPING THROUGH TRENCH3
9
SCALE: NOT TO SCALE
DETAIL
TYPICAL EXTRACTION RISER PIPE THROUGH CONCRETE PAD3
10
SCALE: NOT TO SCALE
DETAIL
TYPICAL EXTRACTION RISER PIPE THROUGH BUILDING3
11
SCALE: NOT TO SCALE
DETAIL
TYPICAL EXTRACTION VENT WITH ACTIVE FAN5
DETAILS II
5
13
SCALE: NOT TO SCALE
DETAIL
TYPICAL INCOMING TRENCH UTILITY DAM5
12
SCALE: NOT TO SCALE
DETAIL
SYSTEM MONITOR3
6" (MIN.)
3" (MIN.)
CONDUIT OR PIPE PENETRATION
NYLON OR POLYPROPYLENE CABLE TIE, TAPE, OR
SPRAY SEAL 2" MIN, ABOVE BASE PENETRATION
OR AS PER GEOMEMBRANE VAPOR BARRIER
MANUFACTURER'S RECOMMENDATIONS
GAS TIGHT BOOT (SEE NOTE 1)
3" MINIMUM COLLAR
EXTENDS INTO
CONCRETE
NOTES:
1.WHERE FOOTINGS, PLUMBING PIPES, ELECTRICAL CONDUITS OR OTHER MATERIALS
PENETRATE THE GEOMEMBRANE VAPOR BARRIER, THE PENETRATIONS SHALL BE SEALED
USING SLEEVES OR BOOTS COMPOSED OF THE SAME MATERIAL AND SEALED IN
ACCORDANCE WITH THE GEOMEMBRANE VAPOR BARRIER MANUFACTURER
RECOMMENDATIONS OR OTHER METHODS AS MAY BE APPROVED BY THE ENGINEER.
1
4 TO SUBGRADE
WIRE/CABLE
CONDUIT DIAMETER
VARIES
EXPANDING
FOAM
2Ø'S
TOP OF CONDUIT
INCOMING
UTILITY
FINISHED GRADESLAB ON
GRADE
TYP. UNIT
EXTERIOR
WALL
END SEAL
END SEAL
SLAB ON
GRADE
1Ø
SLAB ON GRADE
END SEAL
MAIN SERVICE
PULL BOX
COMPACTED
SUBGRADE
SERVICE CONDUIT
TO UTILITY
TRANSFORMER
PAD-MOUNT OR VAULT
UTILITY
PULLBOX
SERVICE CONDUIT
EXTERIOR
WALL
SIKA1A
END SEALFINISHED GRADE
NOTE:
4" CLEAN AGGREGATE, VAPOR BARRIER MEMBRANE, AND PENETRATIONS BOOTS PER DETAIL 6 DRAWING 5 TELEPHONE & CABLE WIRES
MAIN FEED
END SEAL
SEAL WITH URETHANE CAULKING
(SEE GENERAL NOTE K)
F
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1 2 3
4 5 6 7 8
54 6 7 8
F
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D
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B
A
VAPOR INTRUSION MITIGATION SYSTEM DESIGN
SALT LAKE CITY, UTAH
PROJECT:
SITE:
TITLE:
APPROVED BY:
REVIEWED BY:DRAWING NO.:
OF
DRAWN BY:
DESIGN BY:
CHECKED BY:FILE:
PROJECT NO.:
DATE:NOVEMBER 2024
SLC1091.01
6
DATEREV APPDESCRIPTIONDRN
THIS DRAWING MAY NOT BE ISSUED
FOR PROJECT TENDER OR
CONSTRUCTION, UNLESS SEALED.
SIGNATURE
DATEDESIGN DRAWING - NOT FOR CONSTRUCTION
NOV-2024A BRVIMS DESIGN SDB
JN
SDB
JN
EL
BR
Geosyntec Consultants, Inc.
VA License No. 0411001425
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
KEPHART
2555 WALNUT STREET
DENVER, COLORADO
SLC1091.01-C006
C:
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FEB-2025B BRUDEQ COMMENT REVISION SDB
14
SCALE: NOT TO SCALE
DETAIL
TYPICAL VAPOR BARRIER MEMBRANE PIPE PENETRATION6
15
SCALE: NOT TO SCALE
DETAIL
TYPICAL ELECTRICAL CONDUIT SEAL6
DETAILS III
6

Paxton RAP

APPENDIX C
PUBLIC NOTICE

Public Notice
Paxton Development, LLC

A 30-day public comment period will run from (DATE TBD) to receive comments
on the planned remediation of the Paxton residential development project located at
203 to 225 West Paxton Avenue in Salt Lake City, Utah (Site).

The development area includes Salt Lake County Parcels Numbers : 15-12-457-044-
0000, 15-12-457-018-0000, 15-12-457-042-0000, 15-12-457-047-0000 and 15-12-
457-048-0000). Characterization sampling conducted on the Site has identified
elevated concentrations of metals and petroleum related organics in soil and
petroleum organics and volatile organic compounds in shallow groundwater.

Paxton Project, LLC has submitted a Remedial Action Plan (RAP) in accordance
with the requirements of Utah Department of Environmental Quality (UDEQ),
Division of environmental Response and Remediation (DERR), Voluntary Cleanup
Program (VCP). The RAP describes the remediation activities that will be
implemented to address the environmental impacts identified at the Site. These
actions will include excavation and removal of impacted soil, installation and
operation of a vapor intrusion mitigation system, implementation of institutional
controls, and on-going site management in compliance with UDEQ approvals. Copies
of the RAP are available for review during normal business hours at the following
location:

UDEQ/DERR
VCP/Brownfields Section
PO Box 144840
195 N. 1950 West
Salt Lake City, UT 84114-4840
[phone]; Mon - Fri 8am-5pm

Written Comments should be submitted to Ms. Allison Stanley of the UDEQ at
the above address or by email: [e-mail].