I202501 NOPV

Idaho Public Utilities Commission Brad Little,Governor
` `- P.O.Box 83720,Boise,ID 83720-0074 Eric Anderson,President
John R Hammond,Jr.,Commissioner
Dayn Hardie,Commissioner
March 6, 2025, Report#I202501
Dustin Hubbard—Director
Western Regional Pipeline Safety Office, U.S. Department of Transportation
12300 W. Dakota Avenue, Suite 110
Lakewood, CO 80228
Dear Mr. Dustin Hubbard:
On February 4, 2025, the Idaho Public Utilities Commission ("Commission"), Pipeline Safety
Division ("Staff'), (IPUC) pursuant to Chapter 601 of Title 49, United States Code, and per our
60106 Certification agreement, conducted a compliance follow up inspection at the Intermountain
Gas Company's (IGC)Rexburg LNG Plant, located at 5181 W. 3800 S. in Rexburg, Idaho.
Staff observed that some of the Idaho natural gas system owned and operated by Intermountain
Gas Company("Company") was out of compliance on item(s). This results in probable violations
of the pipeline safety regulations Title 49, Code of Federal Regulations, Part 193. The probable
violations are as follows:
PROBABLE VIOLATION(S)
49 CFR & 193.2603 General.
(a) Each component in service, including its support system, must be maintained in a condition
that is compatible with its operational or safety purpose by repair, replacement, or other means.
(b) An operator may not place, return, or continue in service any component which is not
maintained in accordance with this subpart.
(c) Each component taken out of service must be identified in the records kept under& 193.2639.
(d) If a safety device is taken out of service for maintenance, the component being served by the
device must be taken out of service unless the same safety function is provided by an alternate
means.
(e) If the inadvertent operation of a component taken out of service could cause a hazardous
condition, that component must have a tag attached to the controls bearing the words "do not
operate"or words of comparable meaning.
Findinya(s)-
On October 18, 2023, the IPUC conducted a field audit and the LNG tank
saddles/supports were showing signs of cracking. It was also discovered that IGC
personnel had identified cracking in the concrete of the tank foundation on May 5,
2023, and again on October 5, 2023. No corrective action had been taken by IGC until
11331 W.Chinden Blvd.Ste 201-A Boise ID 83714
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IPUC personnel issued a Letter of Concern#I202310 on October 19, 2023.
Intermountain Gas Response
On November 15, 2023, IGC issued a response to Letter of Concern#I202310 stating
"IGC acknowledges the findings brought forth by the IPUC. IGC has contacted a third-
party engineering company to discuss a repair and maintenance plan for tank saddles
and supports." The IPUC accepted this response in good faith and closed out the
concern on November 15, 2023.
Follow Up
On May 15, 2024, a Concrete Cracking Investigation was performed by Forsgren
Associates Inc. ("Forsgren") at the facility to identify and present the findings of a
structural condition assessment for the concrete cracking at the piers of the LNG tank
and for the containment structure walls.
On June 28, 2024, Forsgren sent a Concrete Cracking Investigation letter (signed by
two Professional Engineers) to IGC regarding the Concrete Cracking Investigation at
the facility. The investigation included site visit observations, the concrete analysis
results, a report from a petrographer, and contained recommendations for mitigative
steps to address alkali silica reactivity("ASR"), water intrusion, and to allow concrete
to dry out.
Intermountain Gas Response
On January 9, 2025, IGC provided another follow up response stating"IGC
contacted a third-party engineering company, Forsgren, to discuss a repair and
maintenance plan for tank saddles and supports. Forsgren completed a site
observation on May 15, 2024. IGC is evaluating the recommendations and will
coordinate necessary repairs with Forsgren. A remediation plan will be
developed by July 31, 2025."
Finding(s)•
February 4, 2025, IPUC inspectors conducted an on-site compliance follow-up
inspection at the Rexburg LNG Facility. During the inspection, the tank
saddles/supports were exhibiting signs of crack propagation and additional foundation
spalling. The containment structure walls showed signs of increased cracking and
degradation. When compared to the (2024) Forsgren documentation, the cracking and
spalling have worsened. To date, no measures to prevent further deterioration have
been implemented and no recommendations made by Forsgren have been followed. In
the time since the concrete issues were originally identified(in May of 2023)there have
been multiple truck offloads, weather cycles, and personnel changes. IPUC staff
believes the tank foundation pedestals should be maintained in a condition that is
compatible with its safety purpose by repair,replacement, or other means.
11331 W.Chinden Blvd.Ste 201-A Boise ID 83714
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REOUESTED ACTIONS
Please evaluate these occurrences of probable compliance related issues. If enforcement is
necessary,kindly proceed as appropriate per our 60106-agreement. Otherwise,please provide your
disposition. If you have any questions concerning this communication,please contact me at (208)
334-0333 office, [phone] cell, or email me at Jeff.Brooks(a-),puc.idaho.g_ov.
The Intermountain Gas Company official with authority to bind the Company is as follows:
Pat Darras -Vice President of Engineering & Operations Services
Intermountain Gas Company
400 N 4th St.
Bismarck, ND 58501
Darras, Patrick Patrick.Darras(&mdu.com
We appreciate your attention to this matter and your efforts to promote pipeline safety.
Sincerely,
Y Brooks
Program Manager, Regulated Utilities
Idaho Public Utilities Commission
11331 W.Chinden Blvd.Ste 201-A Boise ID 83714
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