DSHW-2024-004015

January 12, 2024
John Amato
Chevron Environmental Management Company
324 West El Segundo Blvd. (MO-142)
El Segundo, CA 90245
Re:Response to Division’s Comments on
First Half of 2023 Groundwater Monitoring ReportRisk Assessment, and Closure RequestRevised Risk Assessment
Chevron Terminal No. 129-0334, 2350 North 1100 West, Salt Lake City, Utah
EPA ID No. UTT000624577
Dear Mr. Amato:
The Division of Waste Management and Radiation Control (Division) has completed its review of the Chevron’s response to Division’s comments dated October 12, 2023 on the First Half of
2023 Groundwater Monitoring Report, Risk Assessment, and Closure Request for the Chevron Salt Lake Terminal site dated November 30, 2023 and prepared by Arcadis. The response to comments
also includes a revised risk assessment report.
The Division acknowledges that it is the desire or preference of Chevron to achieve clean closure at the site. However, in accordance with Utah Administrative Code (UAC) R315-101-7(b)(2),
the site does not qualify for clean closure based on the site monitoring report and risk assessment.
To achieve clean closure of the site in accordance with UAC R315-101-7(a), Chevron needs to demonstrate the following: 1) Concentrations of chemicals in soil must be below the United
States Environment Protection Agency (USEPA) residential Regional Screen Levels (RSLs). 2) Groundwater contaminant levels must be less than Maximum Contaminant levels (MCLs) or RSLs
for the tap water if MCLs are not available. 3) Residual soil contaminant levels areless than the RSLs for groundwater protection after applying a dilutionattenuation factor of twenty.
4) The residual site contamination is protective of ecological receptors.
Chevron may petition for clean closure of the site when the above conditions are met in the future. Chevron may implement enhanced in-situ bioremediation or other technologies to expedite
achievement of the clean closure.
Alternatively, Chevron may close the site by implementing a site management plan (SMP) and an environmental covenant under the current industrial land use condition. The SMP may include
groundwater monitoring at a reduced frequency. As data shows benzene concentrations are decreasing over time due to natural attenuation processes, Chevron may in the future petition
the Division to cease groundwater monitoring.
In addition, as a part of closure requirements, an ecological risk associated with chemicals of concern at a site needs to be conducted in accordance with the requirements of UAC R315-101-5(j).
Under the current site conditions, Chevron may petition for an ecological risk assessment waiver in accordance with UAC R315-101-5(j)(3). Please submit a request for an ecological
risk assessment waiver by April 30, 2024.
If you have any questions, please contact Hao Zhu at 8015589833 or Paige Walton at 385-515-0086.
Sincerely,
Paige Walton, Program Manager
Corrective Action Section
Division of Waste Management and Radiation Control
PW/HZ/ldw
c: Angela C. Dunn, MD, MPH, Health Officer, Salt Lake County Health Dept.
Dorothy Adams, Deputy Director, Salt Lake County Health Dept.
Ron Lund, Environmental Health Director, Salt Lake County Health Dept.
Carissa Mason, Arcadis (Email) [e-mail]
Lauren Lindham, Arcadis (Email) [e-mail]
Eric Baiden, Toxicologist, Division of Waste Management and Radiation Control
John Amato, Chevron Environmental Management Company (Hand Copy and Email) [e-mail]