I202609 NOPV Response (2)

EXECUTIVE OFFICES
INTERMOUNTAIN GAS COMPANY
555 SOUTH COLE ROAD-P.O.BOX 7608• BOISE,IDAHO 83707•[phone]• FAX:[phone]
August 18,2026
Mr.Jeff Brooks,Programs Manager
Idaho Public Utility Commission
PO Box 83720
Boise,ID 83720-0074
Subject:Response to the Notice of Probable Violation dated July 9,2026(Report#1202609)
Dear Mr.Brooks,
This letter is intended to address two(2)notice of probable violation stemming from a field audit conducted by the
Idaho Public Utilities Commission(IPUC)on July 7-8,2026,of Intermountain Gas Company's(IGC)Pocatello
District pursuant of Chapter 601 Title 49,United States Code.
PROBABLE V10LAT1O2S
1. 49 CFR& 192.605 Procedural Manual for Operations,Maintenance,and Emergencies
General.Each operator shall prepare and follow for each pipeline,a manual of written procedures
for conducting operations and maintenance activities and for emergency response.For
transmission lines,the manual must also include procedures for handling abnormal operations.
This manual must be reviewed and updated by the operator at intervals not exceeding 15 months,
but at least once each calendar year.This manual must be prepared before operations of a pipeline
system commence.Appropriate parts of the manual must be kept at locations where operations
and maintenance activities are conducted.
OPS 500 Regulator Inspection and Maintenance
4.REGULATOR INSPECTION AND MAINTENANCE
4.1.Regulators shall be set to lockup at the designated lockup pressure,with some allowance for
lockup fluctuation,but the regulator shall lockup at a pressure equal to or less than the MAOP
2. 49 CFR 4 192.703 General
(a) No person may operate a segment of pipeline,unless it is maintained in accordance with this
subpart.
3. 49 CFR 4 192.739 Pressure limiting and regulating stations:Inspection and Testing.
(a) Each pressure limiting station,relief device(except rupture discs),and Pressure regulating
station and its equipment must be subjected at intervals not exceeding 15 months,but at least
once each calendar year,to inspections and tests to determine that it is—
(1) In good mechanical condition;
(2) Adequate from the standpoint of capacity and reliability of operation for the service in
which it is employed;
(3) Except as provided in paragraph(b)of this section, set to control or relieve at the correct
pressure consistent with the pressure limits of§192.201(a);and
(4) Properly installed and protected from dirt,liquids,or other conditions that might prevent
proper operation.
Regulator station 48725-RS-60058 primary regulator failed due to a damaged seat.The station was
relieving at 59 psi when the IPUC inspectors and IGC personnel arrived onsite.

EXECUTIVE OFFICES
INTERMOUNTAIN GAS COMPANY
555 SOUTH COLE ROAD-P.O.BOX 7608• BOISE,IDAHO 83707•[phone]• FAX:[phone]
Reference Photos
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48725-RS-60058 Seat Damage 48725-RS-60058 Seat Damage
Intermountain (was Response
IGC respectfully disputes that this finding constitutes as a violation of 49 CFR§ 192.605,§ 192.703, §192.739 or OPS
500—Regulator Station Inspection and Maintenance, Section 4.1 as referenced above.
Per 192.605(a)"General.Each operator shall prepare and follow for each pipeline,a manual of written procedures for
conducting operations and maintenance activities and for emergency response."OPS 500 provides procedures for the
inspection and maintenance of regulating stations within the IGC pipeline system.IGC followed the cited requirements
of OPS 500 as outlined below.
Section 4.1 of OPS 500 addresses how a regulator must be set.In this case,the primary regulator is set to lock up at a
pressure equal to or less than the MAOP as required per OPS 500 section 4.1. The lock up pressure is set to 58 psig
and the MAOP is 60 psig.A piece of weld slag cut the seat,preventing proper operation of the regulator.
Per 192.703(a)"No person may operate a segment of pipeline,unless it is maintained in accordance with this subpart."
IGC records indicate regulator station 48725-RS-60058 has been maintained as required per 192 Subpart M and OPS
500. See below for further maintenance details.
Per 192.739(a):
"Each pressure limiting station, relief device (except rupture discs), and Pressure regulating station and its
equipment must be subjected at intervals not exceeding 15 months,but at least once each calendar year, to
inspections and tests to determine that it is-(1)In good mechanical condition;(2)Adequate from the standpoint
of capacity and reliability of operation for the service in which it is employed; (3) Except as provided in
paragraph(b)of this section,set to control or relieve at the correct pressure consistent with the pressure limits
of§192.201(a); and (4) Properly installed and protected from dirt, liquids, or other conditions that might

EXECUTIVE OFFICES
INTERMOUNTAIN GAS COMPANY
555 SOUTH COLE ROAD-P.O.BOX 7608• BOISE,IDAHO 83707•[phone]• FAX:[phone]
prevent proper operation.".
Annual inspections were conducted in 2026,2025,2024,2023, and 2022 with no issues identified. The most recent
inspection completed on April 16,2026.
While onsite,the regulator was dissembled and the damaged seat was replaced. The regulator was then reassembled,
retested for lock up,and subsequently locked up properly.In the event it could not be repaired at the time of inspection,
OPS 500, Section 7.9 allows 45 days for IGC to cure regulator lock up and operation deficiencies.
4. 49 CFR§ 192.463 External corrosion control: Cathodic protection.
(a)Each cathodic protection system required by this subpart must provide a level of cathodic
protection that complies with one or more of the applicable criteria contained in Appendix D of
this part.If none of these criteria is applicable,the cathodic protection system must provide a level
of cathodic protection at least equal to that provided by compliance with one or more of these
criteria.
5. Appendix D to Part 192—Criteria for Cathodic Protection and Determination of
Measurements
L Criteria for cathodic protection-
A. Steel,cast iron,and ductile iron structures.
(1)A negative(cathodic)voltage of at least 0.85 volt,with reference to a saturated copper-
copper sulfate half-cell.Determination of this voltage must be made with the protective
current applied,and in accordance with sections II and IV of this appendix.
6. 49 CFR§ 192.467 External corrosion control:Electric isolation.
(a)Each buried or submerged pipeline must be electrically isolated from other underground
metallic structures,unless the pipeline and the other structures are electrically interconnected and
cathodically protected as a single unit.
(b)One or more insulating devices must be installed where electrical isolation of a portion of a
pipeline is necessary to facilitate the application of corrosion control.
(c)Except for unprotected copper inserted in a ferrous pipe,each pipeline must be electrically
isolated from metallic casings that are a part of the underground system.However,if isolation is
not achieved because it is impractical,other measures must be taken to minimize corrosion of the
pipeline inside the casing.
(d)Inspection and electrical tests must be made to assure that electrical isolation is adequate.
(e)An insulating device may not be installed in an area where a combustible atmosphere is
anticipated unless precautions are taken to prevent arcing.
(f)Where a pipeline is located in close proximity to electrical transmission tower footings,
ground cables or counterpoise,or in other areas where fault currents or unusual risk of lightning
may be anticipated,it must be provided with protection against damage due to fault currents or
lightning,and protective measures must also be taken at insulating devices.
OPS 402 External Corrosion Control
4.MONITORING PIPELINES UNDER THE INFLUENCE OF CATHODIC
PROTECTION
4.1.Annual cathodic protection survey locations(test points)shall be selected by Corrosion
Control Department personnel and be located at sufficient locations to determine the adequacy of
cathodic protection and electrical isolation.Consider the following areas: dead ends of steel mains
and transmission lines,areas with known corrosion,and areas within the system which possess the
lowest levels of cathodic protection.

EXECUTIVE OFFICES
INTERMOUNTAIN GAS COMPANY
555 SOUTH COLE ROAD-P.O.BOX 7608• BOISE,IDAHO 83707•[phone]• FAX:[phone]
4.1.1.A pipe to soil potential survey shall be conducted annually,not to exceed 15 months to
determine if the following minimum criteria is achieved.
4.1.1.1.A minimum pipe to soil potential shall be equal,or more electronegative than-0.850 V
DC.Voltage(IR)drops other than those across the structure electrolyte boundary shall be
considered for valid interpretation.
4.1.1.1.1.A minimum pipe to soil polarized potential shall be equal,or more electronegative than-
0.850 V DC.Polarized potentials shall be determined by interrupting the protective current
source(s)or through the use of a cathodic protection coupon detailed in NACE TM0497 and
NACE SP0104.
5.CASINGS(Steel Carrier-Casing Isolation Monitoring and Testing)
5.1. Casings shall be inspected for electrical isolation at least once each calendar year,but at
intervals not exceeding 15 months.Casings that are determined to be shorted or casings
where isolation cannot be determined,shall remain on the shorted casing leak survey until
remedial action or removal is completed(see OPS 706—Leak Survey).
5.6. Shorted casings should be cleared if practical by performing the following actions:
5.6.1.Field Operations:
5.6.1.1.Excavate suspected shorted casing end(s).
5.6.1.2.Inspect the carrier pipe for coating defects and remediate if necessary.
5.6.1.3.Inspect the carrier pipe for structural damage and/or corrosion/pipe wall loss and
remediate if necessary.
5.6.1.4.Remove electrolytes(e.g.,water,dirt),damaged casing insulator material,and/or other
conductive materials that may cause the shorted condition.
5.6.1.5.Re-center the carrier pipe inside the casing pipe using approved casing insulators(non-
conductive spacers).
5.6.1.6.Install casing link seals at the ends of the casing to carrier interface.
5.6.2.Corrosion Control personnel:
5.6.2.1.Re-test casing/carrier for electrical isolation after attempts to clear casing shorts have been
performed.
5.6.2.1.1.If testing determines casing is no longer shorted,re-establish casing on annual casing
isolation testing.
5.7. Shorted casings that are not practical to clear shall be scheduled for removal facilitated by
District Management.
Carrier and casing 48725-CA-1115928 has a carrier to soil potential reading of-0.696mV and a casing to
soil potential reading of-0.635mV.These values were below the-0.85mV criteria commonly used to
demonstrate adequate cathodic protection with the requirements of 49 CFR Part 192,Subpart 1.This was
indicative of a short between the casing and carrier pipe.No record of remediation or scheduled removal
were provided.No records of shorted casing leak surveys were provided.
Intermountain Gas Response
IGC respectfully disputes that this finding constitutes as a violation of 49 CFR 192.463 and 192.467 or sections 4 and
5 of OPS 402-External Corrosion Control.
Prior to the date of audit,there was no history of a shorted condition or low cathodic protection(CP)readings at casing
48725-CA-1115928.Thus,a remediation/removal plan or record of leak survey could not be provided at the time of

EXECUTIVE OFFICES
INTERMOUNTAIN GAS COMPANY
555 SOUTH COLE ROAD-P.O.BOX 7608•BOISE,IDAHO 83707•[phone]•FAX:[phone]
the field audit.Further,as required per OPS 402,annual inspections were conducted in 2026,2025,2024,2023,and
2022 with no issues identified.The most recent inspection was completed on March 1,2026.A carrier-to-soil reading
of-1.268 V and a casing-to-soil reading of-.0424 V were obtained,meeting the requirements of 49 CFR Subpart I
and OPS 402 sections 4 and 5.
After discovery of the inadequate readings during the field audit,IGC conducted further investigation and confirmed
a short between the casing and carrier pipe. A remediation plan has since been developed to abandon the casing and
install new steel pipe.IGC has begun the process to obtain permits.A tentative timeline for completion is anticipated
for fall of 2026,pending the receival of permits or any other potential unforeseeable conditions.Until remediation is
complete,leak surveys will be conducted as required per OPS 402 section 5.1.
Additionally,the low CP read associated with the carrier-to-soil has been mitigated at this time with the installation
of anodes.
Please contact Josh Sanders at(701)222-7773 with questions or comments.
Respectfully Submitted,
Pat Darras
Vice President, Engineering& Operations Services
Intermountain Gas Company