DSHW-2024-004866

Deq submit <[e-mail]>
Big West Oil North Salt Lake Refinery SWMU 38 (Lab) RFI Risk Assessment Addendum -
Request for Extension
1 message
Guy M. Partch <[e-mail]>Sun, Feb 25, 2024 at 7:37 PM
To: Karen Wallner <[e-mail]>, WMRC doc submital <[e-mail]>
Cc: Ian Muller <[e-mail]>, "[e-mail]" <[e-mail]>
Hello Karen –

Attached please find a formal request for an extension on the deadline for a BWO response to DWMRC’s communication from January
31, 2024 (attached) that provided comments on the SWMU 38 (Lab) RFI RA Addendum. BWO and DWMRC met on February 13, 2024
and agreed that DWMRC would re-review the RA Addendum and provide a new set of comments. BWO has not yet received those
comments, and requests that a new response deadline be provided with the new comments.

Please feel free to call or email with any questions.

Sincerely,

Guy M. Partch, PG
Vice President
Senior Geologist
Salt Lake City, UT office: 801.333.8444
cell: 218.343.3436
[e-mail]
www.barr.com
If you no longer wish to receive marketing e-mails from Barr, respond to [e-mail] and we will be happy to honor your request.

2 attachments
DSHW-2024-004305.pdf
195K
Response to DWMRC 013124 Letter re SWMU 38 RA Add 022524.pdf
94K

DSHW-2024-004305 195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880
Telephone [phone] • Fax [phone] • T.D.D. 711
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor
Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF WASTE MANAGEMENT
AND RADIATION CONTROL

Douglas J. Hansen
Director

January 31, 2024

Ian Muller, Environmental Engineer
Big West Oil, LLC
333 West Center Street
Salt Lake City, UT 84054

RE: Big West Oil SWMU 38 (Lab) RFI Risk Assessment Addendum
UT045267127

Dear Mr. Muller:

The Division of Waste Management and Radiation Control (Division) has completed its review of the
Solid Waste Management Unit (SWMU) 38 (Lab) Resource Conservation and Recovery Act (RCRA)
Facility Investigation (RFI) Risk Assessment Addendum (Addendum) dated December 27, 2023, for the
Big West Oil, North Salt Lake Refinery (BWO), located in Davis County.

A risk assessment for BWO was previously conducted as part of the 2021 Phase II RFI Assessment.
However, as investigations were still ongoing for SMWU 38, it was not included in the assessment.
This Addendum addresses risk at SWMU 38 and includes additional soil, sub-slab vapor, and
groundwater samples collected during 2022 and 2023.

Based on the review of the Addendum, the Division is providing the following comments:

1. Section 1.0. Please provide all data used for the risk assessment for SWMU 38, including data
collected since 2021. In looking at the Phase II RFI Assessment, the data table (Table 2) for
SWMU 38 is incomplete. While some of the data provided in Table 2-12 could be verified against
the analytical reports in the Appendices, not all the sample results listed in Table 2-12 were
provided.

2. As the information contained in the Addendum supersedes all previous evaluations of SWMU 38,
this document must be a standalone report. Revise the Addendum to include all data, maps, and
evaluations needed to support the SWMU 38 risk assessment and conclusions.
(Over)

Page 2 of 4

3. General. The risk assessment includes discussion of the Refinery worker, industrial worker, and a
composite worker. Provide clarification that the exposure assumptions for all three are consistent
and may be used to represent a single receptor. For clarity, it is suggested that a single term be used
to represent the Refinery worker.

4. The SWMU 38 risk assessment excludes exposure to metals and semi-volatile organic compounds
(SVOCs) in soil. As noted in Sections 5.4 and 6.1, industrial exposure to constituents of potential
concern (COPCs) in soil are solely based on benzene. All COPCs must be included in the
evaluation. Refer to comments on Section 2.0.

5. Section 1.0, fifth paragraph. The text indicates that as concentrations of COPCs in groundwater at
the laboratory were less than the derived exposure point concentration in source wells, groundwater
was not reevaluated. Additional wells were installed in 2022 as step-outs to determine the extent of
contamination as part of the SWMU 38 investigation. Groundwater results from 2022 are available
for wells L-17, L-18, L-19, L-21, L-23, L-24, and L-28 and should be used to reevaluate risk related
to exposure to groundwater. Several other comments are noted with this as follows:

• Table 2-18 from the 2021 RFI Risk Assessment lists benzene, ethylbenzene, Methyl
tert-butyl ether (MTBE), naphthalene and xylenes. Data from eight wells located to the south
and southwest of SWMU 38 were used to derive an exposure point concentration (EPC).
First none of the figures included in the 2021 documents as well as this Addendum show the
direction of groundwater flow. Provide a figure and discuss the representativeness of these
eight wells for assessing exposure at SWMU 38.

• The text states that data from the laboratory wells are less than the EPCs (assumed those
listed in Table 2-18). In looking at the groundwater data associated with the lab as
summarized in Table 6 of the Addendum Phase II RFI Report, there were several volatile
organics detected in the lab wells as well as the center of plume wells that are not listed in
Table 2-18. Please clarify why not all detected COPCs were addressed in the assessment
groundwater. This Addendum must be revised to include all COPCs detected in groundwater
determined to be representative of the conditions at SWMU 38.

• The Addendum Phase II RFI Report further states that the analytical data from the lab is
consistent with groundwater concentrations across the laboratory. It is unclear how this
determination can be made when only a select few contaminants were evaluated. Further,
none of the reports include a statistical evaluation to conclude that groundwater data from the
lab is consistent with groundwater across the facility. Provide statistical demonstration to
support this statement and include all detected contaminants.

• None of the reports include an assessment of risks to groundwater. It is understood that
groundwater will be addressed as a separate SWMU. However, this does not negate potential
exposure to the lab/refinery worker. Provide justification that the groundwater exposure
pathway for the SWMU 38 receptor is incomplete. If lines of evidence cannot be provided to
demonstrate groundwater being an incomplete pathway, the SWMU 38 risk assessment
should be revised to include risks associated with groundwater.

Page 3 of 4

6. Section 2.0. Only constituents with a detection above the industrial Regional Screening Levels
(RSL) were retained as COPCs. As outlined in Utah Administrative Code (UAC) R315-101-
5(f)(3)(ii), all organic contaminants with a minimum of one detection shall be retained as
constituents of potential concern. The COPC reduction process through simple comparison to an
RSL is not acceptable as an initial reduction process nor is frequency of detection. Please also refer
to the Division’s Technical Guidance to Risk Assessment Section 4 for more information on
selection of COPCs. The guidance clearly indicates that point-to-point comparisons and frequency
of detection may not be used to eliminate a constituent as a COPC. The 2021 Phase II Addendum
Report eliminated metals as well as SVOCs as COPCs as individual concentrations were less than
the industrial RSL. However, elimination of metals and SVOCs below the RSLs does not allow for
total risk to be estimated. Unless additional background metals data are available, all metals
(with the exception of arsenic) detected must be retained as COPCs in the risk assessment.
The SWMU 38 risk assessment must be revised for all media to include all metals detected above
background concentrations (or if background is not available, the metal must be retained) and all
organics with a minimum of one detection.

7. Table 2-12. Revise the table to include the sample numbers and all COPCs detected in soil.

8. Section 2.2.12 and Section 3.4. As noted in Comment 6 above, COPCs may not be eliminated based
on comparison to RSLs. Utah Administrative Code R315-101 requires all inorganic and organic
constituents be retained as COPC in the risk assessment unless it can be demonstrated that it is
attributable to background. Revise the soil exposure evaluation accordingly and revise Table 3-12.

9. Section 2.2.17 and Section 3.4. As noted in Comment 6 above, COPCs may not be eliminated based
on comparison to RSLs, and for sub-slab vapor data, this includes comparison to Vapor Intrusion
Screening Levels (VISLs). Utah administrative Code R315-101 requires all inorganic and organic
constituents be retained as COPC in the risk assessment unless it can be demonstrated that it is
attributable to background. Revise the vapor intrusion exposure evaluation accordingly and revise
Table 3-17 and Table 5-17.

10. Section 3.4. The Chronic Daily Intakes (CDI) listed in Table 3-17 could not be verified. Provide the
intermediary calculations used to derive the CDIs and output files from the VISL calculator.

11. Tables 6.1 and 6.2. Revise the tables to include all COPCs, as addressed in the above comments.

12. Risks to Refinery workers must include exposure across all pathways, including soil, vapor
intrusion, and groundwater. As clearly outlined in UAC R315-101-5, cumulative effects risks and
hazards are determined for the combined land use exposure pathways. Revise the report to show the
cumulative effects.

Please provide a response to comments and revised Addendum within 45 days of the date of this letter.

If you have any questions, please call Karen Wallner at 385-499-0218.

Sincerely,

Paige Walton, Manager Corrective Action Section
Division of Waste Management and Radiation Control
Page 4 of 4

PW/KHW/jk

c: Brian Hatch, Health Officer, Davis County Health Department
David W. Spence, Deputy Director, Davis County Health Department
Jay Clark, Environmental Health Director, Davis County Health Department
Marney DeVroom, FJ Management, Inc. (Email)
Faithe Schwartzengraber, Big West Oil, LLC (Email)
Leigh Beem, Johnston Leigh Inc. (Email)
Guy Partch, Barr Engineering Co. (Email)
Sean Moody, Toxicologist, Division of Waste Management and Radiation Control, UDEQ

170 South Main Street, Suite 500, Salt Lake City, UT 84101 | 801.333.8400 | barr.com
February 25, 2024
Karen Wallner
Division of Waste Management and Radiation Control
Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City, UT 84114
Re: Request for Extension - DWMRC Comments on Big West Oil SWMU 38 (Lab) RFI Risk
Assessment Addendum, UT045267127
Dear Karen:
On January 31, 2024, Big West Oil, LLC (BWO) received comments from the Division of Waste
Management and Radiation Control (DWMRC) on the Solid Waste Management Unit (SWMU) 38 (Lab)
Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) Risk Assessment Addendum
(Addendum) dated December 27, 2023 for the BWO North Salt Lake Refinery located in Davis County,
Utah. This correspondence requested a response from BWO within 45 days (March 16, 2024).
Upon review of DWMRC’s comments, BWO and DWMRC held a virtual meeting on February 13, 2024 to
discuss the comments. During this meeting, it was determined that DWMRC would re-review and provide
new comments on the Addendum in the context of the approved Risk Assessment Work Plan (July 21,
2021) and the approved initial RFI Risk Assessment (December 16, 2021).
The purpose of this request for extension is to release BWO from the March 16, 2024 response deadline.
We request that DWMRC provide an updated response date with the updated comments, when
communicated.
If you have any questions or would like additional information, please contact Leigh Beem at 801-726-
6845 or [e-mail], Ian Muller at 801-296-7716 or [e-mail], or myself
at 801-333-8444 or [e-mail].
On behalf of BWO,

Guy Partch, PG
Barr Engineering Co.

CC: Leigh Beem, Johnston Leigh, Inc.
Ian Muller, Big West Oil, LLC