DSHW-2025-000597

From: Jasin Olsen <[e-mail]>
Date: Wed, Jan 29, 2025 at 11:41 AM
Subject: Re: Submittal of Corrective Action Plan for SWMU GW-4.1A Benzol Plant Area East, Former Geneva Steel Facility
To: Mustoe, Brett <[e-mail]>
Cc: Paige Walton <[e-mail]>, Rupnow, Mark R <[e-mail]>, Wiltse, Mark <[e-mail]>, Russell
Christensen <[e-mail]>, Lunardini, Bob <[e-mail]>, Kusel, Greg <[e-mail]>,
Messersmith, Tammi <[e-mail]>, Cannon, Lawrence <[e-mail]>, Ethan Upton
<[e-mail]>
Brett,
Please find attached comments for the Benzol Plant Biosparge CAP. Let me know if you have any questions. Also, we
haven't forgotten Area 6. It will be coming shortly.
Thanks,
Jasin
On Wed, Dec 18, 2024 at 5:04 PM Mustoe, Brett <[e-mail]> wrote:
All,
Please see attached the corrective action plan for the biosparging system at SWMU GW-4.1A Benzol Plant Area East, Former Geneva Steel Facility, Vineyard, Utah. Also
attached is a transmittal letter along with approval to submit signed by both Permittees.
For your reference, design information is included in Appendix B (calculations), Appendix C (drawings), and Appendix D (bill of materials).
Thank you,
Brett
L:\DCS\Projects\USS_Geneva RCRA CA\CAMU Construction Support 2018-2020\400 - Technical\CAMU GW Monitoring
Plan\Revised December 2024N. Brett Mustoe, PG
Principal Geologist / Project Manager
Environment, Remediation
C 1-801-673-2135
[e-mail]
AECOM
756 East Winchester Street, Suite 400, Salt Lake City, Utah 84107
T 1-801-904-4000
www.aecom.com
https://mail.google.com/mail/u/0/?tab=rm&ogbl#inbox/FMfcgzQZSsKvHhHzclzxhkVKGfPTQCQW 1/1
Risk Assessment Comments for the Corrective Action Plan Implementation Report,
Geneva Benzol Plant Area East, Corrective Action Plan
Ecological Risk Assessment (ERA)
1.An ecological risk waiver was granted.
Human Health Risk Assessment (HHRA)
1.Section 3.0, 4.0, and 7.2.2 indicate that the primary COPCs are benzene and naphthalene.
Section 7.2.2 indicates that once the primary COPCs reach the corrective action levels shown
in Section 4.0 then a cumulative risk level will be calculated. Per Utah Administrative Code
R315-101-5(f)(5) and the Divisions Technical Guide for Risk Assessment (TGRA) Section
6.1, all detected COPCs must be included in the cumulative risk assessment using either the
maximum COPC concentration or a refined 95% upper confidence level (95 UCL) as the
exposure point concentration. Please update the Plan to indicate that all detected COPCs will
be evaluated in the cumulative risk assessment.
2.Section 4.0 indicates that the Corrective Action Levels (CALs) are based on a cancer risk
level of 1E-04. However, if multiple COPCs are equal to or close to the threshold of 1E-04,
then the cumulative risk will likely exceed the risk threshold. Rather than a carcinogenic risk
of 1E-04, the Division suggests re-calculating the CALs and receptors based on a
carcinogenic risk level of 1E-06. Additionally, please use the most recent toxicity data based
on the hierarchy of human health toxicity values (refer to Section 5.1 of the TGRA) to
recalculate the CALs.
3.Section 5.5 indicates that a Site Management Plan (SMP) and Environmental Covenant (EC)
will be instituted with land use controls to provide protection for human health and the
environment. After review of the Human Health Risk Evaluation dated October 20, 2020
(DSHW-2020-015281), land use controls will be required not only for soil vapor but also for
soil and groundwater which are within the risk range of 1E-04 and 1E-06. Please update the
Plan to indicate that the SMP and EC will include controls on all impacted media.