4-Exhibit B DERR Review of Environmental Assessment.pdf

195 North 1950 West • Salt Lake City, UT Mailing Address: P.O. Box 144840 • Salt Lake City, UT 84114-4840

Telephone (801) 536-4100 • Fax (801) 359-8853 • T.D.D. 800 346-3128 www.deq.utah.gov

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State of Utah

SPENCER J. COX

Governor

DEIDRE HENDERSON

Lieutenant Governor

Department of Environmental Quality

Tim Davis

Commissioner

DIVISION OF ENVIRONMENTAL

RESPONSE AND REMEDIATION

Brent H. Everett

Director

ERRC-105-26

August 10, 2026

Ryan Blair Park City Municipal Corporation 445 Marsac Avenue P.O. Box 1480 Park City, Utah 84060

RE: DERR Review of Environmental Assessment

Bonanza Park VCP #C134, 1665 Bonanza Drive, Park City

Dear Mr. Blair:

The Division of Environmental Response and Remediation (DERR) has reviewed the following documents as required by the provisions of the Voluntary Cleanup Program (VCP):

● Phase I Environmental Site Assessment, Wasatch Environmental, January 13, 2015;

● Phase I Environmental Site Assessment, Terracon, September 22, 2017;

● Limited Site Investigation, Terracon, September 21, 2017; and

● Phase II Environmental Site Assessment, Terracon, April 23, 2024.

Together these documents are intended to serve as the Environmental Assessment (EA) required under the VCP.

The DERR has attached review comments for your information. Please address these comments in a Remedial Action Plan. If you have any questions, please contact me at

(385) 391-8132.

Sincerely, Lincoln Grevengoed, Project Manager Division of Environmental Response and Remediation

LGG/es

Lincoln Grevengoed (Aug 10, 2026 10:08:53 MDT) Lincoln Grevengoed https://utahgov.na1.echosign.com/verifier?tx=CBJCHBCAABAAPtO2SBgNC7skCW6DOLNyTfZMHA3P-gUu

Enclosure: Technical Comments cc: Nathan Brooks, Environmental Health Director, Summit County Health Department

Julie Cobleigh, District Engineer, Utah Department of Environmental Quality

DERR Review Comments Bonanza Park: Voluntary Cleanup Program - Environmental Assessment

General Comments:

1. Please submit a Remedial Action Plan (RAP) for the DERR’s review. Please see the following VCP fact sheet to help with the development of a RAP. The future use and design of the property can be considered as part of the remedy. If waste is left on the property above unrestricted land use, long-term site management will be necessary.

2. Please submit a Quality Assurance Project Plan (QAPP), ensure the QAPP addresses elements required in EPA’s QAPP guidance and includes a Level 3 Reporting Package for all analytical data generated for the project. The Level 3 Reporting Package should include a case narrative, all analytical results and qualifiers, surrogates, and batch Quality Control (QC) results (Matrix Spike/Matrix Spike Duplicates, Lab Control Samples, Method Blanks, etc.). Additionally, please ensure that the laboratory reporting limits are below the proposed screening levels.

3. Analytical data in the Voluntary Cleanup Plan (VCP) is typically screened against current EPA Regional Screening Levels (RSLs), Initial Screening Levels (for TPH and TRPH), Maximum Contaminant Levels (MCLs), and Vapor Intrusion Screening Levels (VISLs).

Please include these criteria in the Remedial Action Plan as applicable.

4. Based on the Phase 1 Environmental Site Assessment (ESA), the site has been vacant for the last few years. Please inform the DERR if any activities have occurred at the site since that time that may have led to new impacts at the site.

5. Potential impacts may be present under the foundation of the buildings and the asphalt.

Please propose a strategy to manage the potential unknowns in the RAP. This could include possible lifts, drains, sumps, and oil water separators. For example, the Environmental Assessment (EA) notes a forty-year-old oil-water separator at the former auto repair shop.

This feature was inaccessible during the Phase 1 ESA and Limited Site Investigation. If encountered, this feature would need to be characterized and remediated.

6. Please note that agency acceptance and a 30-day public comment period are necessary before implementing proposed remedial action under the VCP (if the cleanup will be phased, multiple public comment periods may be necessary). Public comments, if any, must be addressed before beginning remedial action. As there has been recent public interest, additional public outreach should be considered to ensure the public is educated about the site and has an opportunity to provide feedback on the proposed remedy.

7. The DERR will collect split samples, to be analyzed at a separate laboratory from the laboratory selected by the applicant for sample analysis, as an independent quality assurance measure. The applicant is responsible for paying for the split samples' analytical costs.

Please designate and set up a state-certified laboratory for the analysis of split samples.

https://lf-public.deq.utah.gov/WebLink/ElectronicFile.aspx?docid=392764&eqdocs=DERR-2022-032990&dbid=0&repo=Public https://lf-public.deq.utah.gov/WebLink/ElectronicFile.aspx?docid=392764&eqdocs=DERR-2022-032990&dbid=0&repo=Public

8. Please note that the Petroleum Storage Tanks associated with Facility Identification No. 7000065 have been carved out of the Voluntary Cleanup Agreement. Please coordinate future activities with the DERR PST Project Manager.

End DERR Comments