DERR-2024-010591

1

Rockwell Solutions, Inc., 718 E. Bridger Lane, Elk Ridge, UT 84651 801-361-2930 [e-mail]

Rockwell Solutions, Inc.
718 E Bridger Lane
Elk Ridge, UT 84651
[phone]
July 16, 2024

Dipikaben Patel
Last Chance Stores
1620 W Center Street
Provo, Utah 84601

RE: Excavation Report
Last Chance #6 (Facility ID #1000078; Release OKU)
910 W Center Street
Provo, Utah 84601

Dear Mr. Patel:

Rockwell Solutions, Inc. submits this excavation report for the above-referenced site.

INTRODUCTION

Underground Storage Tanks (USTs) were removed from the above-referenced site on May 29,
2024. The canopy was demolished and removed from the site prior to the UST removal.

Closure samples collected during tank closure activities indicated soil below the northwest
dispenser contained total petroleum hydrocarbon – diesel range organics (TPH-DRO)
concentrations exceeding the Tier 1 level. All other soil samples were below Initial Screening
Levels (ISLs).

The objective of the excavation was to remove impacted soil from the area of the northwest
dispenser.

EXCAVATION ACTIVITIES

On June 14, 2024, soil around and below the northwest dispenser was removed. Soil was screened
with a photoionization detector (PID) to determine the extent of contamination. Apparent
unimpacted soil was segregated and stockpiled separately from the apparent impacted soil

The final dimensions of the excavation were approximately fifteen feet long by twenty feet wide by
nine feet deep. The top three to four feet of soil were unimpacted. 62.6 tons of impacted soil were
removed and hauled off for disposal.

Soil confirmation samples were collected from the walls and bottom of the excavation. The
samples were analyzed for MTBE, benzene, toluene, ethylbenzene, xylenes, naphthalene
Excavation Report, Last Chance #6, Provo, Utah
2

Rockwell Solutions, Inc., 718 E. Bridger Lane, Elk Ridge, UT 84651 801-361-2930 [e-mail]

(MBTEXN) and total petroleum hydrocarbons – gasoline range organics (TPH-GRO) using EPA
analytical method 8260b and TPH-diesel range organics (TPH-DRO) using EPA method 8015b.
Sample locations are shown on Figure 1 and corresponding depths are shown on Table 1.

Groundwater was encountered at the bottom of the excavation and a groundwater sample was
collected and analyzed for MBTEXN and TPH-GRO using EPA Method 8260b and TPH-DRO
using EPA Method 8015b.

SOIL TYPE

The native soil at the site consists of sandy gravel and cobbles to at least ten feet bg.

SOIL DISPOSAL

All soil removed from the excavation was hauled to ET Technologies soil disposal facility in Salt
Lake City.

The excavation was backfilled and compacted with clean, imported backfill.

ANALYTICAL RESULTS

The soil analytical results from the excavation are presented on Table 1. All hydrocarbon
concentrations in all samples were below Tier 1 levels and ISLs. Laboratory reports are attached.

The groundwater analytical results from the UST closure are presented on Table 2. The only
constituents to exceed ISLs were benzene in the south groundwater sample in the tank basin and
TPH-DRO in the excavation. Both slightly exceeded their respective ISL and are well below Tier 1
levels. Laboratory reports are attached.

CONCLUSIONS AND RECOMMENDATIONS

 Soil samples from the tank basin and three of the four dispensers were below ISLs
 62.6 tons of impacted soil were removed from the northwest dispenser area and hauled away
for disposal
 All excavation soil confirmation samples were below ISLs
 A groundwater sample from the tank basin slightly exceeded the ISL for benzene and the
sample from the excavation slightly exceeded the ISL for TPH-DRO, but both are well
below Tier 1 levels

Rockwell Solutions recommends closing the release and issuing a No Further Action letter for the
site.

Excavation Report, Last Chance #6, Provo, Utah
3

Rockwell Solutions, Inc., 718 E. Bridger Lane, Elk Ridge, UT 84651 801-361-2930 [e-mail]

Thank you for the opportunity to work with you on this project. If you have any questions or
concerns, please feel free to contact me at your convenience.

Sincerely,

David S Hansen
Certified UST Consultant CC0130
Rockwell Solutions, Inc.

cc: Alex Thompson, DERR
Water
Gas
Sewer
NORTH
Sample Location Last Chance #6
910 W Center Street
Provo, Utah
Approx. scale in feet
00 20
Figure 1 UST Closure Map
TB-N
GW-N
USC-1
TB-S
GW-S
D-NE
D-SE
TB-E
USC-2
D-NW
D-SW
USC-2
rWate
sGa
S weer
St rm raino D
Water
Gas
Sewer
NORTH
Soil Sample Location Last Chance #6
910 W Center Street
Provo, Utah
Approx. scale in feet
00 20
Figure 2 Excavation Map
TB-E
USC-2
S, 8’
W, 8’
N, 8’
E, 8’
B-9’
Excavation
Groundwater Sample Location
Sample
Depth
(feet) Date
Benzene
(mg/kg)
Toluene
(mg/kg)
Ethyl-
benzene
(mg/kg)
Xylenes
(mg/kg)
Naph-
thalene
(mg/kg)
MTBE
(mg/kg)
TPH-
GRO
(mg/kg)
TPH-DRO
(mg/kg)
0.2 9 5 142 51 0.3 150 500
0.9 25 23 142 51 0.3 1,500 5,000
TB-N, 10' 10 5/29/2024 <0.01 <0.03 <0.03 <0.03 <0.03 <0.01 <0.279 <56
TB-S, 10' 10 5/29/2024 <0.01 <0.02 <0.02 <0.02 <0.02 <0.01 <0.248 <54
D-NW, 4' 4 5/29/2024 <0.01 <0.03 <0.03 <0.03 <0.03 <0.01 108 4,150
D-NE, 3' 3 5/29/2024 <0.01 <0.02 <0.02 <0.02 <0.02 <0.01 <0.264 101
D-SE, 3' 3 5/29/2024 <0.01 <0.02 <0.02 <0.02 <0.02 <0.01 <0.262 <59
D-SW, 3' 3 5/29/2024 <0.01 <0.02 <0.02 <0.02 <0.02 <0.01 <0.322 <64
N, 8' 8 6/14/2024 <0.01 <0.03 <0.03 <0.08 <0.03 <0.02 <0.281 <58
E, 8' 8 6/14/2024 <0.01 <0.03 <0.03 <0.08 <0.03 <0.02 <0.267 <55
S, 8' 8 6/14/2024 <0.01 <0.02 <0.02 <0.07 <0.02 <0.01 <0.247 <53
W, 8' 8 6/14/2024 <0.01 <0.03 <0.03 <0.08 <0.03 <0.02 <0.295 93
B, 9' 9 6/14/2024 <0.01 <0.03 <0.03 <0.08 <0.03 <0.02 <0.276 <54
MBTEXN and TPH-GRO analyzed by EPA Method 8260.
TPH-DRO analyzed by EPA Method 8015
Green shading = area that was later excavated
UST Closure Samples
Excavation Samples
RBCA Tier 1 Screening Levels
Table 1
Initial Screening Levels
Last Chance #6, UST Facility No 1000078, LUST No. OKU
910 W Center Street, Provo, Utah
Soil Sample Results
Page 1 of 2
Sample Date
Benzene
(mg/L)
Toluene
(mg/L)
Ethyl-
benzene
(mg/L)
Xylenes
(mg/L)
Naph-
thalene
(mg/L)
MTBE
(mg/L)
TPH-
GRO
(mg/L)
TPH-DRO
(mg/L)
0.005 1 0.7 10 0.7 0.2 1 1
0.3 3 4 10 0.7 0.2 10 10
GW-N 5/29/2024 <0.005 <0.012 <0.012 <0.012 <0.012 <0.005 <0.125 <1
GW-S 5/29/2024 0.022 0.0335 <0.012 <0.012 <0.012 <0.005 <0.125 <1
Excavation 6/14/2024 <0.005 0.031 <0.012 0.048 <0.012 <0.008 <0.125 1.2
MBTEXN and TPH-GRO analyzed by EPA Method 8260
TPH-DRO analyzed by EPA Method 8015
mg/L = milligrams per liter, which approximates parts per million.
Pink-shaded cells = exceeds Initial Screening Level
RBCA Tier 1 Screening
UST Closure Samples
Table 2
Groundwater Analytical Results
Last Chance #6, UST Facility No 1000078, LUST No. OKU
910 W Center Street, Provo, Utah
Initial Screening Levels
The analyses presented on this report were performed in accordance with the
National Environmental Laboratory Accreditation Program (NELAP) unless
noted in the comments, flags, or case narrative. If the report is to be used for
regulatory compliance, it should be presented in its entirety, and not be
altered.
Client Service Contact: 801.262.7299
Rockwell Solutions, Inc
Attn: Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
Work Order: 24F1238
Project: Last Chance #6
6/17/2024
Approved By:
Mark Broadhead, Project Manager
9632 South 500 West Sandy, Utah 84070
Serving the Intermountain West since 1953
801.262.7299 Main 866.792.0093 Fax www.ChemtechFord.com
Page 1 of 9
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Rockwell Solutions, Inc
Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
PO#:
Receipt:
Date Reported:
Project Name:
6/14/24 10:36 @ 4.8 °C
6/17/2024
Last Chance #6
Sample ID: N, 8'
Lab ID: 24F1238-01Matrix: Solid
Flag(s)Units
Analysis
Date/Time
Date Sampled: 6/14/24 8:45
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
Inorganic
%6/17/246/14/240.1 CTF800085.7Total Solids
MBTEXn
mg/kg dry 6/14/246/14/240.01 EPA 8260D/5030BNDBenzene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDEthylbenzene
mg/kg dry 6/14/246/14/240.02 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDNaphthalene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDToluene
mg/kg dry 6/14/246/14/240.08 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/kg dry 6/14/246/14/240.281 EPA 8260B/C 5035A/[CALC]NDGasoline Range Organics
Diesel Range
mg/kg dry 6/15/246/14/2458EPA 8015 CNDDiesel Range Organics
Project Name: Last Chance #6 CtF WO#: 24F1238
www.ChemtechFord.com
Page 2 of 9Page 2 of 9
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Rockwell Solutions, Inc
Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
PO#:
Receipt:
Date Reported:
Project Name:
6/14/24 10:36 @ 4.8 °C
6/17/2024
Last Chance #6
Sample ID: E, 8'
Lab ID: 24F1238-02Matrix: Solid
Flag(s)Units
Analysis
Date/Time
Date Sampled: 6/14/24 8:50
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
Inorganic
%6/17/246/14/240.1 CTF800091.0Total Solids
MBTEXn
mg/kg dry 6/14/246/14/240.01 EPA 8260D/5030BNDBenzene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDEthylbenzene
mg/kg dry 6/14/246/14/240.02 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDNaphthalene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDToluene
mg/kg dry 6/14/246/14/240.08 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/kg dry 6/14/246/14/240.267 EPA 8260B/C 5035A/[CALC]NDGasoline Range Organics
Diesel Range
mg/kg dry 6/15/246/14/2455EPA 8015 CNDDiesel Range Organics
Project Name: Last Chance #6 CtF WO#: 24F1238
www.ChemtechFord.com
Page 3 of 9Page 3 of 9
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Rockwell Solutions, Inc
Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
PO#:
Receipt:
Date Reported:
Project Name:
6/14/24 10:36 @ 4.8 °C
6/17/2024
Last Chance #6
Sample ID: S, 8'
Lab ID: 24F1238-03Matrix: Solid
Flag(s)Units
Analysis
Date/Time
Date Sampled: 6/14/24 9:10
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
Inorganic
%6/17/246/14/240.1 CTF800093.6Total Solids
MBTEXn
mg/kg dry 6/14/246/14/240.01 EPA 8260D/5030BNDBenzene
mg/kg dry 6/14/246/14/240.02 EPA 8260D/5030BNDEthylbenzene
mg/kg dry 6/14/246/14/240.01 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/kg dry 6/14/246/14/240.02 EPA 8260D/5030BNDNaphthalene
mg/kg dry 6/14/246/14/240.02 EPA 8260D/5030BNDToluene
mg/kg dry 6/14/246/14/240.07 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/kg dry 6/14/246/14/240.247 EPA 8260B/C 5035A/[CALC]NDGasoline Range Organics
Diesel Range
mg/kg dry 6/15/246/14/2453EPA 8015 CNDDiesel Range Organics
Project Name: Last Chance #6 CtF WO#: 24F1238
www.ChemtechFord.com
Page 4 of 9Page 4 of 9
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Rockwell Solutions, Inc
Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
PO#:
Receipt:
Date Reported:
Project Name:
6/14/24 10:36 @ 4.8 °C
6/17/2024
Last Chance #6
Sample ID: W, 8'
Lab ID: 24F1238-04Matrix: Solid
Flag(s)Units
Analysis
Date/Time
Date Sampled: 6/14/24 9:00
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
Inorganic
%6/17/246/14/240.1 CTF800092.8Total Solids
MBTEXn
mg/kg dry 6/14/246/14/240.01 EPA 8260D/5030BNDBenzene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDEthylbenzene
mg/kg dry 6/14/246/14/240.02 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDNaphthalene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDToluene
mg/kg dry 6/14/246/14/240.08 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/kg dry 6/14/246/14/240.259 EPA 8260B/C 5035A/[CALC]0.295Gasoline Range Organics
Diesel Range
mg/kg dry 6/15/246/14/2454EPA 8015 C93Diesel Range Organics
Project Name: Last Chance #6 CtF WO#: 24F1238
www.ChemtechFord.com
Page 5 of 9Page 5 of 9
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Rockwell Solutions, Inc
Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
PO#:
Receipt:
Date Reported:
Project Name:
6/14/24 10:36 @ 4.8 °C
6/17/2024
Last Chance #6
Sample ID: B, 9'
Lab ID: 24F1238-05Matrix: Solid
Flag(s)Units
Analysis
Date/Time
Date Sampled: 6/14/24 9:05
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
Inorganic
%6/17/246/14/240.1 CTF800092.4Total Solids
MBTEXn
mg/kg dry 6/14/246/14/240.01 EPA 8260D/5030BNDBenzene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDEthylbenzene
mg/kg dry 6/14/246/14/240.02 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDNaphthalene
mg/kg dry 6/14/246/14/240.03 EPA 8260D/5030BNDToluene
mg/kg dry 6/14/246/14/240.08 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/kg dry 6/14/246/14/240.276 EPA 8260B/C 5035A/[CALC]NDGasoline Range Organics
Diesel Range
mg/kg dry 6/15/246/14/2454EPA 8015 CNDDiesel Range Organics
Project Name: Last Chance #6 CtF WO#: 24F1238
www.ChemtechFord.com
Page 6 of 9Page 6 of 9
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Rockwell Solutions, Inc
Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
PO#:
Receipt:
Date Reported:
Project Name:
6/14/24 10:36 @ 4.8 °C
6/17/2024
Last Chance #6
Sample ID: Excavation
Lab ID: 24F1238-06Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 6/14/24 9:30
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 6/14/246/14/240.005 EPA 8260D/5030BNDBenzene
mg/L 6/14/246/14/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L J-LOW-C6/14/246/14/240.008 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/L 6/14/246/14/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 6/14/246/14/240.012 EPA 8260D/5030B0.031Toluene
mg/L 6/14/246/14/240.038 EPA 8260D/5030B0.048Xylenes, total
Gasoline Range
mg/L 6/14/246/14/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Diesel Range
mg/L 6/14/246/14/241.0 EPA 8015 C1.2Diesel Range Organics
Project Name: Last Chance #6 CtF WO#: 24F1238
www.ChemtechFord.com
Page 7 of 9Page 7 of 9
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Rockwell Solutions, Inc
Dave Hansen
718 East Bridger Lane
Elk Ridge, UT 84651
PO#:
Receipt:
Date Reported:
Project Name:
6/14/24 10:36 @ 4.8 °C
6/17/2024
Last Chance #6
Report Footnotes
Abbreviations
ND = Not detected at the corresponding Minimum Reporting Limit (MRL).
1 mg/L = one milligram per liter or 1 mg/kg = one milligram per kilogram = 1 part per million.
1 ug/L = one microgram per liter or 1 ug/kg = one microgram per kilogram = 1 part per billion.
1 ng/L = one nanogram per liter or 1 ng/kg = one nanogram per kilogram = 1 part per trillion.
On calculated parameters, there may be a slight difference between summing the rounded values shown on the report
vs the unrounded values used in the calculation.
Flag Descriptions
J-LOW-C = Estimated low due to low recovery of CCV
Project Name: Last Chance #6 CtF WO#: 24F1238
www.ChemtechFord.com
Page 8 of 9Page 8 of 9
Page 9 of 9