DERR-2024-011185

Rockwell Solutions, Inc., 718 E. Bridger Lane, Elk Ridge, UT 84651 801-361-2930 [e-mail]
1
Rockwell Solutions, Inc.
718 E Bridger Lane
Elk Ridge, UT 84651
[phone]
September 13, 2024

Tha Imran
West Valley Sinclair
1950 W 3500 South
West Valley City, Utah

Re: Subsurface Investigation
West Valley Sinclair Facility ID: 4000381
1950 W 3500 South Release ID: OKG
West Valley City, Utah

Dear Ms. Imran:

Rockwell Solutions, Inc. has completed subsurface investigation activities at the above-referenced
facility in accordance with a request from the Utah Division of Environmental Response and
Remediation (DERR) guidelines.

INTRODUCTION

The site is an active gas station in West Valley City, Utah. The fueling system consists of one
8,000-gallon and one 12,000-gallon underground storage tanks (USTs) that contain gasoline. There
are two dispensers at the site.

During a DERR site inspection on March 27, 2023, gasoline was observed dripping from a newly
installed o-ring on the meter at dispenser 1 / 2. The new meter had been installed less than one
week prior to the inspection. The dispenser was shut down and Petroleum Equipment Company
replaced the o-ring. A site map is provided as Figure 1.

METHODOLOGY

Because monitoring wells are on site to monitor release NOU and groundwater is only seven to
eight feet deep, it was determined to collect groundwater samples from surrounding wells to
investigate impacts from the release. MW-8A is located directly south of dispenser 1 / 2 at the edge
of the canopy. MW-5A is located north of the release area and MW-9A and MW-4A are located
southeast of the release area. See Figure 1.

On August 23, 2024, groundwater samples were collected from MW-4A, MW-5A, MW-8A, and
MW-9A. Groundwater samples were collected from each monitoring well using a disposable
bailer. Each groundwater sample was immediately placed on ice and retained under chain-of-
custody documentation until relinquished to the laboratory. Samples were submitted for analysis of
Subsurface Investigation, Solitude Ski Resort, Salt Lake City, UT, Facility #4001332, Release OHY

Rockwell Solutions, Inc., 718 E. Bridger Lane, Elk Ridge, UT 84651 801-361-2930 [e-mail]
2
MTBE, benzene, toluene, ethylbenzene, total xylenes, naphthalene (MBTEXN) and total petroleum
hydrocarbons (TPH) - gasoline range organics (GRO) using EPA Method 8260. Chemtech-Ford
conducted the laboratory analyses. Laboratory reports are attached.

RESULTS
Table 1 lists the analytical results of the groundwater samples collected during the subsurface
investigation for release OKG as well as the results of the NOU investigations. The hydrocarbon
concentrations (or lack of) in all samples are very similar to the most recent samples in 2023. The
benzene concentration in the sample from MW-8A, nearest to the release, is slightly higher, but the
TPH-GRO concentration is slightly lower. The laboratory analytical reports and chain-of-custody
records for groundwater samples collected during the subsurface investigation are attached.

Based on the 8/23/24 sampling results, it does not appear that the release has impacted the
groundwater at the site. Rockwell Solutions recommends closing release OKG and issuing a No
Further Action letter.

Please feel free to contact me should you have any questions or concerns at 801-361-2930.

Sincerely,

David S Hansen
Rockwell Solutions, Inc.
Certified UST Consultant CC130

cc: Alex Thompson, DERR
Figure 1
NORTH
Approx. scale in feet
00 20
West Valley Sinclair
1950 W 3500 South
West Valley City, Utah
MSiteap
Monitoring Well
MW-9A
rWate
wSeer
Elecrcti
mComunication
Sr aintomDr
D-2D-3D-4D-5
D-1
USC-2
TB-SE
USC-1 Dispenser 1 / 2
MW-4A
MW-5A
MW-8A
TPH-GRO TPH-DRO Benzene Toluene Ethylbenzene Xylenes Naphthalene MTBE
MW-1A 02/14/18 0.580 <1.0 0.013 <0.012 0.029 <0.012 <0.012 <0.005
07/14/22 0.148 0.479 0.0179 0.00555 0.0263 0.0623 0.0399 0.00248
01/27/23 0.183 B 0.693 0.00195 <0.00100 0.000164 J 0.000466 <0.00500 <0.00100
07/19/23 0.0623 J 0.673 0.00333 <0.00100 <0.00100 <0.00300 <0.00500 <0.00100
MW-2A 02/14/18 3.85 3.1 0.092 0.064 0.054 0.768 0.066 <0.005
07/14/22 28.900 8.120 0.427 0.518 0.380 4.780 0.361 <0.0200
01/27/23 14.200 7.100 0.347 0.294 0.242 2.570 0.286 <0.0200
1/27/202 14.400 7.130 0.331 0.288 0.231 2.450 0.245 <0.0100
07/19/23 6.560 Q 2.900 0.310 0.238 0.179 1.520 0.182 <0.0200
7/19/202 5.550 2.840 0.327 0.246 0.187 1.580 0.179 <0.0200
MW-3A 02/14/18 0.173 <1.0 <0.005 <0.012 <0.012 <0.012 <0.012 <0.005
07/14/22 0.103 0.0780 0.00274 0.000408 0.00103 0.00230 J 0.00599 B <0.000101
01/27/23 0.0767 B,J 0.215 0.00113 0.000302 0.000377 J 0.000480 <0.00500 <0.00100
07/19/23 0.0494 B,J 0.211 0.000757 J <0.00100 <0.00100 <0.00300 <0.00500 <0.00100
MW-4 02/14/18 <0.125 <1.0 <0.005 <0.012 <0.012 <0.012 <0.012 <0.005
07/14/22 0.294 0.817 0.0167 0.000419 0.00418 0.00384 0.00260 B,J 0.000107 J
01/27/23 0.113 B 0.999 0.000598 J <0.00100 <0.00100 <0.00300 <0.00500 <0.00100
07/19/23 0.341 1.020 0.0200 0.000449 0.00460 0.0146 <0.00500 <0.00100
MW-4A 02/14/18 <0.125 <1.0 <0.005 <0.012 <0.012 <0.012 <0.012 <0.005
07/14/22 0.0752 J 0.305 0.000102 J <0.00100 0.000167 J 0.000487 0.00141 B,J <0.00100
01/27/23 0.0500 B,J 0.304 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.00100
07/19/23 0.0399 B,J 0.292 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.00100
08/23/24 <0.125 NA <0.005 <0.012 <0.012 <0.038 <0.012 <0.008
MW-5A 02/14/18 0.783 1.6 <0.005 <0.012 0.041 <0.012 0.033 <0.005
07/14/22 0.0819 J 0.724 0.000159 J <000100 <0.00100 0.000427 0.00179 B,J <0.00100
01/27/23 0.0943 B,J 0.833 0.000390 J <000100 <0.00100 <0.00300 0.00216 J <0.00100
07/19/23 0.0509 B,J 0.783 <0.00100 <000100 <0.00100 <0.00300 0.00250 J <0.00100
08/23/24 <0.125 NA <0.005 <0.012 <0.012 <0.038 <0.012 <0.008
Table 1
Groundwater Analytical Results
West Valley Sinclair, 1950 W 3500 South, West Valley City, UT (Fac ID #4000381)
Sample
Location
Date
Groundwater Concentrations in mg/L
Page 1 of 2
TPH-GRO TPH-DRO Benzene Toluene Ethylbenzene Xylenes Naphthalene MTBE
Table 1
Groundwater Analytical Results
West Valley Sinclair, 1950 W 3500 South, West Valley City, UT (Fac ID #4000381)
Sample
Location
Date
Groundwater Concentrations in mg/L
MW-6A 02/14/18 2.15 4.2 <0.005 <0.012 <0.012 <0.012 0.750 <0.005
07/14/22 1.940 1.900 0.00167 <0.00100 0.00697 0.000820 0.173 <0.00100
01/27/23 0.730 1.880 0.00124 <0.00100 0.00549 0.000433 0.134 <0.00100
07/19/23 1.120 B 3.460 0.000668 J <0.00500 0.0114 <0.0150 0.0933 <0.00500
MW-7A 02/14/18 <0.125 <1.0 <0.005 <0.012 <0.012 <0.012 <0.012 <0.005
07/14/22 0.184 0.366 <0.00100 <0.00100 0.000401 J 0.000505 0.0488 <0.00100
01/27/23 0.137 B 0.424 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.00100
07/19/23 0.105 B 0.529 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.00100
MW-8A 02/14/18 0.605 1.3 0.037 <0.012 <0.012 <0.012 <0.012 <0.005
07/14/22 1.850 1.740 0.0339 0.00194 0.00927 0.00379 0.256 <0.00100
07/14/22 1.440 1.570 0.0338 0.00189 0.00923 0.00381 0.320 <0.00100
01/27/23 0.645 1.870 0.0149 <0.0100 <0.0100 0.00397 J 0.170 <0.0100
07/19/23 2.300 2.210 0.0340 0.332 0.0657 0.305 0.195 <0.00500
08/23/24 2.040 NA 0.105 0.012 0.110 0.134 0.662 <0.008
MW-9A 02/12/18 0.444 1.8 <0.005 <0.012 <0.012 <0.012 <0.012 <0.005
07/14/22 0.547 0.985 0.0168 0.000464 0.00129 0.000899 0.0816 <0.000101
01/27/23 <0.500 1.390 0.00563 <0.00100 <0.00100 0.000580 0.0252 <0.00100
07/19/23 0.293 B,J 1.260 0.00660 <0.00100 0.000468 J <0.00300 0.0115 <0.00100
08/23/24 <0.125 NA 0.008 <0.012 <0.012 <0.038 0.034 <0.008
1.0 1.0 0.005 1.0 0.7 10 0.7 0.2
10 10 0.3 3.0 4.0 10 0.7 0.2
Samples from 2/14/18 - 7/9/23 were collected as part of the investigation of release NOU
TPH-GRO = Total petroleum hydrocarbons-gasoline range organics
TPH-DRO = Total petroleum hydrocarbons-diesel range organics
mg/L = milligrams per liter, which approximates parts per million
ISL = Initial Screening Level
Initial Screening Level
RBCA Tier 1
Page 2 of 2
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: 24H2236
Project: West Valley Sinclair
8/30/2024
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 7
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:
8/23/24 17:19 @ 10.6 °C
8/30/2024
West Valley Sinclair
Sample ID: MW-4A
Lab ID: 24H2236-01Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 8/23/24 16:45
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 8/27/248/27/240.005 EPA 8260D/5030BNDBenzene
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 8/27/248/27/240.008 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDToluene
mg/L 8/27/248/27/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 8/27/248/27/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Project Name: West Valley Sinclair CtF WO#: 24H2236
www.ChemtechFord.com
Page 2 of 7Page 2 of 7
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:
8/23/24 17:19 @ 10.6 °C
8/30/2024
West Valley Sinclair
Sample ID: MW-5A
Lab ID: 24H2236-02Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 8/23/24 16:25
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 8/27/248/27/240.005 EPA 8260D/5030BNDBenzene
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 8/27/248/27/240.008 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDToluene
mg/L 8/27/248/27/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 8/27/248/27/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Project Name: West Valley Sinclair CtF WO#: 24H2236
www.ChemtechFord.com
Page 3 of 7Page 3 of 7
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:
8/23/24 17:19 @ 10.6 °C
8/30/2024
West Valley Sinclair
Sample ID: MW-8A
Lab ID: 24H2236-03Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 8/23/24 16:05
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 8/27/248/27/240.005 EPA 8260D/5030B0.105Benzene
mg/L 8/27/248/27/240.012 EPA 8260D/5030B0.110Ethylbenzene
mg/L 8/27/248/27/240.008 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/L 8/27/248/27/240.012 EPA 8260D/5030B0.662Naphthalene
mg/L 8/27/248/27/240.012 EPA 8260D/5030B0.012Toluene
mg/L 8/27/248/27/240.038 EPA 8260D/5030B0.134Xylenes, total
Gasoline Range
mg/L 8/27/248/27/240.125 EPA 8260B/C /5030A/[CALC]2.04Gasoline Range Organics
Project Name: West Valley Sinclair CtF WO#: 24H2236
www.ChemtechFord.com
Page 4 of 7Page 4 of 7
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:
8/23/24 17:19 @ 10.6 °C
8/30/2024
West Valley Sinclair
Sample ID: MW9A
Lab ID: 24H2236-04Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 8/23/24 15:45
Preparation
Date/Time
Sampled By: David Hansen
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 8/27/248/27/240.005 EPA 8260D/5030B0.008Benzene
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 8/27/248/27/240.008 EPA 8260D/5030BNDMethyl tert-Butyl Ether (MTBE)
mg/L 8/27/248/27/240.012 EPA 8260D/5030B0.034Naphthalene
mg/L 8/27/248/27/240.012 EPA 8260D/5030BNDToluene
mg/L 8/27/248/27/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 8/27/248/27/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Project Name: West Valley Sinclair CtF WO#: 24H2236
www.ChemtechFord.com
Page 5 of 7Page 5 of 7
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:
8/23/24 17:19 @ 10.6 °C
8/30/2024
West Valley Sinclair
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.
Project Name: West Valley Sinclair CtF WO#: 24H2236
www.ChemtechFord.com
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