DERR-2024-004358

Vapor Study Report
Brent Redd Property
148 East Center Street Monticello, Utah
Facility ID #5000003 Release ID GZQ
December 19, 2023 | Terracon Project No. AL067003
Prepared for:
Utah Department of Environmental Quality
Division of Environmental Response and Remediation
Salt Lake City, Utah
6952 South High Tech Drive
Midvale, Utah 84057
P [phone]
Terracon.com
Facilities |Environmental |Geotechnical | Materials i
December 19, 2023
Utah Department of Environmental Quality
Division of Environmental Response and Remediation
195 North 1950 West
Salt Lake City, Utah 84114
Attn: Mr. Mark Crim
E:[e-mail]
Re:Vapor Study Report
Brent Redd Facility
148 East Center Street, Monticello, Utah
Facility Identification No. 5000003, Release ID GZQ
Terracon Project No. AL067003
Dear Mr. Crim:
Terracon Consultants, Inc. (Terracon) is pleased to submit this Vapor Study Report
documenting a sampling event conducted under Work Assignment GZQ-55 at the Brent Redd
facility (Facility ID 5000003, Release ID GZQ), located at 148 East Center Street, Monticello,
Utah.
Terracon has performed this work pursuant to Work Plan GZQ-55-TER dated August 21, 2023.
This work was conducted under Terracon's contract (Contract Number 216383) with the
Division of Environmental Response and Remediation (DERR).
We appreciate the opportunity to have performed these services for you. Please contact our
office at [phone] if you have questions regarding this information or if we can
provide any other services.
Sincerely,
Terracon Consultants, Inc.
Amy Austin Andy King, P.G.
UST Consultant 238 Authorized Project Reviewer
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Brent Redd | GZQ-55
December 19, 2023 | Terracon Project No. AL067003
Facilities |Environmental |Geotechnical | Materials ii
TABLE OF CONTENTS
1.0 INTRODUCTION.............................................................................................1
1.1 Site Description ..................................................................................... 1
1.2 Project Background ................................................................................ 1
1.3 Standard of Care .................................................................................... 1
1.4 Additional Scope Limitations .................................................................... 1
2.0 METHODOLOGY .............................................................................................2
2.1 Indoor Air Sampling Event ....................................................................... 2
2.2 Sub-Slab Vapor Sampling ........................................................................ 2
2.3 Laboratory Analyses ............................................................................... 3
3.0 RESULTS ........................................................................................................4
3.1 Indoor Air Sample .................................................................................. 4
3.2 Sub Slab Vapor Samples ......................................................................... 4
4.0 DATA SUMMARY ............................................................................................5
4.1 Indoor Air ............................................................................................. 5
4.2 Sub Slab Vapor ...................................................................................... 5
5.0 CONCLUSIONS ...............................................................................................5
APPENDICES
Appendix A Exhibit 1 Vapor Sample Locations
Appendix B Table 1 VOCs in Indoor Air and Soil Gas
Appendix C Chain of Custody and Laboratory Data Sheets
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Brent Redd | GZQ-55
December 19, 2023 | Terracon Project No. AL067003
Facilities |Environmental | Geotechnical | Materials 1
1.0 INTRODUCTION
1.1 Site Description
Terracon conducted a vapor study event at the Brent Redd facility (Facility ID 5000003,
Release ID GZQ), located at 148 East Center Street, Monticello, Utah. Exhibit 1 (Appendix
A) is a site diagram that shows the sample locations and most recent concentrations of
benzene reported in groundwater.
1.2 Project Background
A release of petroleum hydrocarbons from underground storage tanks has been documented
at the site. In an effort to better evaluate impacts, the DERR requested a study to assess
potential indoor air vapor threats at the Brent Redd site as well as the Monticello Inn, a
third-party structure overlying the dissolved-phase plume migrating from the Brent Redd
release site.
The objective of this investigation was to evaluate the potential presence of volatile organic
chemicals (VOCs) in sub-slab soil gas and indoor air (above relevant regulatory screening
levels) associated with the petroleum hydrocarbon plume identified on the site.
1.3 Standard of Care
Terracon’s services were performed in a manner consistent with generally accepted
practices of the profession undertaken in similar studies in the same geographical area
during the same time period. Please note that Terracon does not warrant the work of
laboratories, regulatory agencies, or other third parties supplying information used in the
preparation of the report. These services were performed in accordance with the scope of
services agreed with DERR, our client, as reflected in our proposal, and were not restricted
by ASTM E1903-19.
1.4 Additional Scope Limitations
Findings, conclusions, and recommendations resulting from these services are based upon
information derived from the on-site activities and other services performed under this
scope of services. Such information is subject to change over time. Certain indicators of the
presence of hazardous substances, petroleum products, or other constituents may have
been latent, inaccessible, unobservable, non-detectable, or not present during these
services. We cannot represent that the site contains no hazardous substances, toxic
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Brent Redd | GZQ-55
December 19, 2023 | Terracon Project No. AL067003
Facilities |Environmental | Geotechnical | Materials 2
materials, petroleum products, or other latent conditions beyond those identified during this
sampling event. Subsurface conditions may vary from those encountered at specific borings
or wells or during other surveys, tests, assessments, investigations, or exploratory services.
The data, interpretations, findings, and our recommendations are based solely upon data
obtained at the time and within the scope of these services.
2.0 METHODOLOGY
On November 7 and 8, 2023, prior to the indoor air sampling activities, Terracon conducted
a pre-study site visit to inventory chemicals used in the buildings and other possible sources
of VOCs at the site that could introduce the VOCs into air within or around the building. No
significant sources of VOCs were identified.
From November 27 to 29, 2023, a total of two sub-slab soil gas sampling points were
installed as vapor pins (VP-1 and VP-2) and a total of five indoor air samples (IA-1 to IA-5)
were set up inside the Monticello Inn. Exact locations were chosen in the field based on
access limitations at the time of Terracon’s on-site sampling and are shown on Exhibit 1
(Appendix A).
2.1 Indoor Air Sampling Event
A total of five Summa™ canisters were placed inside the Monticello Inn building.
Three canisters were placed within the ground-level living quarters: IA-1 was placed
in the office space, IA-2 was placed in Room 101, and IA-3 was placed in Room 102
of the hotel. Two canisters were placed in the crawl space beneath the building (IA-4
and IA-5). The canisters were placed in the selected rooms/areas such that the
sample inlets were located between 3 and 5 feet above the floor in the approximate
location of the breathing zone.
Each air sample was collected over a 24-hour period using a regulatory flow-control device
affixed to a batch-certified, 6-liter capacity, Summa™ stainless steel canister supplied by
H&P Mobile Geochemistry, Inc. in Carlsbad, California.
2.2 Sub-Slab Vapor Sampling
One vapor pin (VP-1) was installed in the basement utility room of the Monticello Inn and
one vapor pin was installed in the office area of the Brent Redd service station (VP-2).
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Brent Redd | GZQ-55
December 19, 2023 | Terracon Project No. AL067003
Facilities |Environmental | Geotechnical | Materials 3
The vapor pins were installed by Direct Push Services and completed with a Vapor PinTM
assembly consisting of a permanent flush-mount brass barb fitting with a silicone sleeve to
seal the hole.
Sub-slab vapor points were allowed to equilibrate at least twenty-four hours prior to a
sample collection. Prior to sample collection, Terracon conducted leak detection tests at
each sample location. The first test was to evaluate the sample train for leaks by conducting
a shut-in test on the sample train after it was fully assembled. The shut-in test was
conducted by closing the valve to the vapor pin and applying a vacuum to the closed sample
train while monitoring the pressure on an inline vacuum gauge for one minute. If the
sample train held a constant vacuum pressure, the sample train was deemed to be airtight.
Following the shut-in test, the air that was evacuated from the sample train to generate the
vacuum was purged.
A second leak detection test was conducted by introducing helium gas at a concentration
between 15 and 20 percent into a sampling shroud placed over the vapor pin. If helium was
measured in the sampling train at a concentration of greater than 7,500 parts per million
(ppm), it indicated there was potential breakthrough in the sampling train and all
connections were re-examined and tightened where necessary and re-tested. Three helium
tests were conducted at each location prior to sampling.
Each sub-slab sample was collected over a 5-minute period using a batch-certified, 1-liter
capacity, Summa™ stainless steel canister supplied by H&P Mobile Geochemistry, Inc. in
Carlsbad, California.
2.3 Laboratory Analyses
All soil gas samples were submitted to H&P Mobile Geochemistry under standard chain-of-
custody protocol for analyses for volatile organic compounds (VOCs) using EPA Method TO-
15, under standard turnaround of 10 business days. The Work Plan stated the sampling
canisters provided by the laboratory would be individually-certified clean canisters;
however, a miscommunication with the laboratory resulted in the use of batch-certified
canisters for this sampling event.
Copies of the laboratory analytical reports and sample chain-of-custody records are included
in Appendix C.
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Brent Redd | GZQ-55
December 19, 2023 | Terracon Project No. AL067003
Facilities |Environmental | Geotechnical | Materials 4
3.0 RESULTS
3.1 Indoor Air Sample
Analytical results for VOCs in the indoor air sample are summarized in Table 1 (Appendix B).
The results are compared to the United States Environmental Protection Agency’s (EPA’s)
Regional Screening Levels (RSLs) for Indoor Air, for both Residential and Industrial
scenarios. The RSLs are based on a Target Cancer Risk of 1x10-6 (one-in-a-million) and are
listed in Table 1 with values for Total Hazard Quotient (THQ) levels of 1.
All indoor air samples were collected from the Monticello Inn.
Indoor air sample IA-1 was collected from the office space. The concentration of
benzene, chloroform, and 1,2-dichloroethane exceeded the EPA RSL for Industrial air.
The concentration of ethylbenzene exceeded the EPA RSL for Residential air.
Indoor air sample IA-2 was collected from Room 101. The concentration of benzene
exceeded the EPA RSL for Industrial air.
Indoor air sample IA-3 was collected from Room 102. The concentration of benzene
exceeded the EPA RSL for Residential air.
Indoor air samples IA-4 and IA-5 were collected from the basement crawl space
beneath the building. Both samples exceeded the EPA RSL for benzene in Residential
air.
Other analytes were reported above the laboratory detection limits in all indoor samples;
however no other chemicals exceeded an indoor air screening level.
3.2 Sub Slab Vapor Samples
Analytical results for VOCs in the sub-slab soil gas samples are summarized in Table 1
(Appendix B). The results are compared to the EPA’s Target Sub-Slab and Near-source Soil
Gas Concentration Vapor Intrusion Screening Levels (VISLs) for both Residential and
Commercial scenarios. The VISLs are based on a Target Cancer Risk of 1x10-6 (one-in-a-
million) and are listed in Table 1 with values for THQ levels of 1.
Sub-slab sample VP-1 was collected from the basement of the Monticello Inn. All
VOCs were not detected above the laboratory reporting limit with the exception of
m,p-xylene. The concentration of m,p-xylene detected was below the EPA VISL.
Sub-slab sample VP-2 was collected from the Brent Redd building. No VOCs were
detected above the laboratory reporting limit.
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Brent Redd | GZQ-55
December 19, 2023 | Terracon Project No. AL067003
Facilities |Environmental | Geotechnical | Materials 5
4.0 DATA SUMMARY
The following presents a summary of the investigation results.
4.1 Indoor Air
Based on this sampling event, indoor air inside the Monticello Inn exceeds EPA screening
levels for benzene, chloroform, 1,2-dichloroethane, and ethylbenzene.
4.2 Sub Slab Vapor
Based on this sampling event, sub-slab soil gas beneath the Brent Redd facility and the
Monticello Inn did not exceed an EPA screening level.
5.0 CONCLUSIONS
This investigation did not identify concentrations of VOCs in sub-slab vapor samples that
indicate the potential for vapor intrusion; however, indoor air samples collected from inside
the Monticello Inn did report exceedances of EPA screening levels. The concentrations of VOCs
reported in the two indoor air samples collected from the basement were less than the
concentrations of VOCs reported from the office and rooms.
Indoor air and soil gas sampling is known to have a high variability due to preferential
pathways for vapor accumulation, however, the non-detect result for benzene in soil gas does
not correlate with the detections of benzene in indoor air.
The lack of detection of benzene and other VOCs in the sub-slab samples suggests the
detections of VOCs in the indoor air samples may not be related to the petroleum
hydrocarbon plume. Although a review of chemicals stored at the hotel was conducted, a
variety of other potential sources could account for the detected VOCs. For example,
cleansers, air fresheners, aerosol sprays, and vehicle exhaust are known to produce airborne
VOCs, and these types of materials would be reasonably likely to be encountered in motel
rooms.
As the potential for vapor intrusion fluctuates with seasonal variability, and concentrations of
petroleum hydrocarbons exceeded indoor air screening levels, Terracon recommends
conducting four quarters of indoor air sampling at the Monticello Inn.
Terracon appreciates being of service to you on this project. If you have any questions,
require additional information, or need additional assistance, please contact us.
APPENDIX A
Exhibits
APPENDIX B
Table
Table 1 - VOCs in Indoor Air and Soil Gas
Brent Redd Property, 148 East Center Street, Monticello, Utah
Terracon Project No. AL067003 Task GZQ-55
Analyte CAS Method Units Resident Air
RSL
Industrial Air
RSL
VISL
Residential
VISL
Commercial Result RDL Result RDL Result RDL Result RDL Result RDL Result RDL Result RDL
BENZENE 71-43-2 TO-15 µg/m3 0.36 1.6 12 52.4 2.2 0.32 2.1 0.32 1.5 0.32 0.52 0.32 0.61 0.32 ND 0.6 ND 0.6
BROMODICHLOROMETHANE 75-27-4 TO-15 µg/m3 0.076 0.33 2.53 11 ND 0.68 ND 0.68 ND 0.68 ND 0.68 ND 0.68 ND 2.7 ND 2.7
BROMOFORM 75-25-2 TO-15 µg/m3 2.6 11 85.1 372 ND 1.0 ND 1.0 ND 1.0 ND 1.0 ND 1.0 ND 4.2 ND 4.2
BROMOMETHANE 74-83-9 TO-15 µg/m3 5.2 22 174 730 ND 0.39 ND 0.39 ND 0.39 ND 0.39 ND 0.39 ND 1.6 ND 1.6
CARBON DISULFIDE 75-15-0 TO-15 µg/m3 730 3100 24300 102000 0.73 0.32 ND 0.32 ND 0.32 ND 0.32 ND 0.32 ND 1.3 ND 1.3
CARBON TETRACHLORIDE 56-23-5 TO-15 µg/m3 0.47 2 15.6 68.1 ND 0.64 ND 0.64 ND 0.64 ND 0.64 ND 0.64 ND 1.3 ND 1.3
CHLOROBENZENE 108-90-7 TO-15 µg/m3 52 220 1740 7300 ND 0.47 ND 0.47 ND 0.47 ND 0.47 ND 0.47 ND 1.9 ND 1.9
CHLOROETHANE 75-00-3 TO-15 µg/m3 NE NE 348000 1460000 ND 0.27 ND 0.27 ND 0.27 ND 0.27 ND 0.27 ND 1.6 ND 1.6
CHLOROFORM 67-66-3 TO-15 µg/m3 0.12 0.53 4.07 17.8 0.59 0.25 ND 0.25 ND 0.25 ND 0.25 ND 0.25 ND 1.0 ND 1.0
CHLOROMETHANE 74-87-3 TO-15 µg/m3 94 390 3130 13100 1.1 0.21 1.2 0.21 0.97 0.21 0.85 0.21 0.91 0.21 ND 0.8 ND 0.8
CHLORODIBROMOMETHANE 124-48-1 TO-15 µg/m3 NE NE NE NE ND 1.7 ND 1.7 ND 1.7 ND 1.7 ND 1.7 ND 3.5 ND 3.5
1,2-DIBROMOETHANE 106-93-4 TO-15 µg/m3 0.0047 0.02 0.156 0.681 ND 0.78 ND 0.78 ND 0.78 ND 0.78 ND 0.78 ND 3.1 ND 3.1
1,2-DICHLOROBENZENE 95-50-1 TO-15 µg/m3 210 880 6950 29200 ND 0.61 ND 0.61 ND 0.61 ND 0.61 ND 0.61 ND 2.4 ND 2.4
1,3-DICHLOROBENZENE 541-73-1 TO-15 µg/m3 NE NE NE NE ND 0.61 ND 0.61 ND 0.61 ND 0.61 ND 0.61 ND 2.4 ND 2.4
1,4-DICHLOROBENZENE 106-46-7 TO-15 µg/m3 0.26 1.1 8.51 37.2 ND 0.61 ND 0.61 ND 0.61 ND 0.61 ND 0.61 ND 2.4 ND 2.4
1,2-DICHLOROETHANE 107-06-2 TO-15 µg/m3 0.11 0.47 3.6 15.7 0.53 0.41 ND 0.41 ND 0.41 ND 0.41 ND 0.41 ND 1.6 ND 1.6
1,1-DICHLOROETHANE 75-34-3 TO-15 µg/m3 1.8 7.7 58.5 256 ND 0.41 ND 0.41 ND 0.41 ND 0.41 ND 0.41 ND 1.6 ND 1.6
1,1-DICHLOROETHENE 75-35-4 TO-15 µg/m3 210 880 6950 29200 ND 0.40 ND 0.40 ND 0.40 ND 0.40 ND 0.40 ND 1.6 ND 1.6
CIS-1,2-DICHLOROETHENE 156-59-2 TO-15 µg/m3 NE NE NE NE ND 0.40 ND 0.40 ND 0.40 ND 0.40 ND 0.40 ND 1.6 ND 1.6
TRANS-1,2-DICHLOROETHENE 156-60-5 TO-15 µg/m3 NE NE NE NE ND 0.40 ND 0.40 ND 0.40 ND 0.40 ND 0.40 ND 1.6 ND 1.6
1,2-DICHLOROPROPANE 78-87-5 TO-15 µg/m3 0.76 3.3 25.3 110 0.56 0.47 ND 0.47 ND 0.47 ND 0.47 ND 0.47 ND 1.9 ND 1.9
CIS-1,3-DICHLOROPROPENE 10061-01-5 TO-15 µg/m3 NE NE NE NE ND 0.46 ND 0.46 ND 0.46 ND 0.46 ND 0.46 ND 1.8 ND 1.8
TRANS-1,3-DICHLOROPROPENE 10061-02-6 TO-15 µg/m3 NE NE NE NE ND 0.46 ND 0.46 ND 0.46 ND 0.46 ND 0.46 ND 1.8 ND 1.8
DICHLOROTETRAFLUOROETHANE 76-14-2 TO-15 µg/m3 NE NE NE NE ND 0.71 ND 0.71 ND 0.71 ND 0.71 ND 0.71 ND 2.8 ND 2.8
ETHYLBENZENE 100-41-4 TO-15 µg/m3 1.1 4.9 37.4 164 4.4 0.44 0.53 0.44 ND 0.44 ND 0.44 ND 0.44 ND 1.8 ND 1.8
4-ETHYLTOLUENE 622-96-8 TO-15 µg/m3 NE NE NE NE 0.60 0.50 ND 0.50 ND 0.50 ND 0.50 ND 0.50 ND 2.0 ND 2.0
TRICHLOROFLUOROMETHANE 75-69-4 TO-15 µg/m3 NE NE NE NE 1.1 0.56 1.1 0.56 1.1 0.56 1.2 0.56 1.2 0.56 ND 2.3 ND 2.3
DICHLORODIFLUOROMETHANE 75-71-8 TO-15 µg/m3 100 4400 3480 14600 ND 1.0 ND 1.0 ND 1.0 ND 1.0 ND 1.0 ND 4.0 ND 4.0
1,1,2-TRICHLOROTRIFLUOROETHANE 76-13-1 TO-15 µg/m3 5200 22000 174000 730000 ND 0.77 ND 0.77 ND 0.77 ND 0.77 ND 0.77 ND 3.1 ND 3.1
HEXACHLORO-1,3-BUTADIENE 87-68-3 TO-15 µg/m3 0.13 0.56 4.25 18.6 ND 2.7 ND 2.7 ND 2.7 ND 2.7 ND 2.7 ND 11 ND 11
METHYLENE CHLORIDE 75-09-2 TO-15 µg/m3 100 1200 3380 40900 5.3 0.35 ND 0.35 ND 0.35 ND 0.35 0.35 0.35 ND 1.4 ND 1.4
METHYL BUTYL KETONE 591-78-6 TO-15 µg/m3 31 130 1040 4380 ND 0.83 ND 0.83 ND 0.83 ND 0.83 ND 0.83 ND 3.3 ND 3.3
2-BUTANONE (MEK)78-93-3 TO-15 µg/m3 5200 22000 174000 730000 40 0.60 0.75 0.60 ND 0.60 ND 0.60 ND 0.60 ND 2.4 ND 2.4
4-METHYL-2-PENTANONE (MIBK)108-10-1 TO-15 µg/m3 3100 13000 104000 438000 1.1 0.83 ND 0.83 ND 0.83 ND 0.83 ND 0.83 ND 3.3 ND 3.3
STYRENE 100-42-5 TO-15 µg/m3 1000 4400 34800 146000 9.9 0.43 ND 0.43 ND 0.43 ND 0.43 ND 0.43 ND 1.7 ND 1.7
1,1,2,2-TETRACHLOROETHANE 79-34-5 TO-15 µg/m3 0.048 0.21 1.61 7.05 ND 0.70 ND 0.70 ND 0.70 ND 0.70 ND 0.70 ND 2.8 ND 2.8
1,1,1,2-TETRACHLOROETHANE 630-20-6 TO-15 µg/m3 0.38 1.7 12.6 55.2 ND 0.70 ND 0.70 ND 0.70 ND 0.70 ND 0.70 ND 2.8 ND 2.8
TETRACHLOROETHENE 127-18-4 TO-15 µg/m3 11 47 360 1570 ND 0.69 ND 0.69 ND 0.69 ND 0.69 ND 0.69 ND 2.8 ND 2.8
TOLUENE 108-88-3 TO-15 µg/m3 5200 22000 174000 730000 57 0.76 30 0.76 1.9 0.76 0.80 0.76 0.99 0.76 ND 3.1 ND 3.1
1,2,4-TRICHLOROBENZENE 120-82-1 TO-15 µg/m3 2.1 8.8 69.5 292 ND 1.9 ND 1.9 ND 1.9 ND 1.9 ND 1.9 ND 7.5 ND 7.5
1,1,1-TRICHLOROETHANE 71-55-6 TO-15 µg/m3 5200 22000 174000 730000 ND 0.55 ND 0.55 ND 0.55 ND 0.55 ND 0.55 ND 2.2 ND 2.2
1,1,2-TRICHLOROETHANE 79-00-5 TO-15 µg/m3 0.18 0.77 5.85 25.6 ND 0.55 ND 0.55 ND 0.55 ND 0.55 ND 0.55 ND 2.2 ND 2.2
TRICHLOROETHENE 79-01-6 TO-15 µg/m3 0.48 3 15.9 99.7 ND 0.55 ND 0.55 ND 0.55 ND 0.55 ND 0.55 ND 2.2 ND 2.2
1,2,4-TRIMETHYLBENZENE 95-63-6 TO-15 µg/m3 63 260 2090 8760 1.4 0.50 ND 0.50 ND 0.50 ND 0.50 ND 0.50 ND 2.0 ND 2.0
1,3,5-TRIMETHYLBENZENE 108-67-8 TO-15 µg/m3 63 260 2090 8760 0.50 0.50 ND 0.50 ND 0.50 ND 0.50 ND 0.50 ND 2.0 ND 2.0
VINYL CHLORIDE 75-01-4 TO-15 µg/m3 0.17 2.8 5.59 92.9 ND 0.13 ND 0.13 ND 0.13 ND 0.13 ND 0.13 ND 0.5 ND 0.5
M,P-XYLENE 178601-23-1 TO-15 µg/m3 100 440 3480 14600 13 0.44 1.8 0.44 0.97 0.44 0.57 0.44 0.66 0.44 3.7 1.8 ND 1.8
O-XYLENE 95-47-6 TO-15 µg/m3 100 440 3480 14600 5.1 0.44 0.70 0.44 ND 0.44 ND 0.44 ND 0.44 ND 1.8 ND 1.8
NE:Not Established.<:Less than Reported Detection Limit (RDL).µg/m3:micrograms per cubic meter.
11/28/2023 11/28/2023 11/28/2023 11/28/2023 11/28/2023
IA-3 IA-4 IA-5 VP-1 VP-2
E312005-03 E312005-04 E312005-05 E312005-06 E312005-07
11/28/2023
Qualifiers (Q):
Date Collected 11/28/2023
EPA RSL:Environmental Progetcition Agency Regional Screening Levels for Residential and Industrial Air (May 2023, TR=1E-06; THQ=1.0).
Bold value exceeds Method Detection Limit (MDL). Blue italicized non-detect results (e.g., <0.0100) exceed one or more of the screening levels.
EPA VISL: Environmental Protection Agency Target Sub-Slab and Near-source Soil Gas Concentration (TSSNSGC) Vapor Intrusion Screening Level (VISL); December 2023.
Client Sample ID IA-1 IA-2
Lab Sample ID E312005-01 E312005-02
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APPENDIX C
Chain of Custody and Laboratory Data Sheets