I202405 NOPV Response

EXECUTIVE OFFICES
INTERMOUNTAIN GAS COMPANY
555 SOUTH COLE ROAD-P.O.BOX 7608• BOISE,IDAHO 83707•[phone]• FAX:[phone]
May 23,2024
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 April 16,2024(Report#I202405)
Dear Mr.Brooks,
This letter is intended to address one(1)notice of probable violation stemming from a field inspection conducted by
the Idaho Public Utilities Commission(IPUC)on April 8-9,2024,in the Nampa district of Intermountain Gas
Company(IGC)pursuant of Chapter 601 Title,49,United States Code.
PROBABLE VIOLATION
1. 49 CFR§ 192,605 Procedural manual for operations.maintenance,and emergencies.
(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.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 Station Inspection and Maintenance
4.1 Regulators shall be set to lockup at the designated set pressure,unless setting during flow
conditions allows the regulator to lockup at a pressure equal to or less than the MAOP.For example,
a regulator,may be set during flow conditions provided the set pressure plus the known droop(e.g.,
the difference between lockup and delivery pressure)does not exceed MAOP.
2. 49 CFR§ 192,739 (a) (4)Pressure limiting and regulating stations: Inspection and testing.
Pressure limiting and regulating stations:Inspection and testing—reads:Properly installed and protected from
dirt, liquids, or other conditions that might prevent proper operation.
Find)'
Regulator station 48371-RS-1289867(Dithiazine),48371-RS-59980(oil),48371-RS-59992,48371-RS-
59976(metal shavings)failed to lock up on the primary side and 48371-RS-59977(weld slag)on the
secondary side.Metal shavings,compressor oil or Dithiazine debris were found in the diaphragms and
regulator bodies when disassembled.All issues were fixed on-site upon disassembly,debris removal,and
were then retested with adequate lock up.
Intermountain Gas Response
IGC acknowledges the findings brought forth by the IPUC.
Regulator Station 48371-RS-1289867: The regulator was dissembled, cleaned, and reassembled onsite and
subsequently locked up properly.The primary regulator locked up as expected during the 2023 and 2022 annual
inspections. IGC is continuing to monitor the application of filtration devices for regulator stations that fail
lock-up two or more times in a three-year period.A follow up inspection to check for the presence of dithiazine
has been scheduled for July 2024.
Regulator Station 48371-RS-59980: Oil was discovered in the filter and on top of the boot during the annual
inspection and maintenance performed on March 12,2024. The boot was replaced,and the filter and regulator
body were cleaned. IGC performed a follow up investigation on April 1, 2024, and discovered oil in the boot

EXECUTIVE OFFICES
INTERMOUNTAIN GAS COMPANY
555 SOUTH COLE ROAD-P.O.BOX 7608•BOISE,IDAHO 83707•[phone]•FAX:[phone]
and pilot.The regulator was disassembled,cleaned,and reassembled.IGC performed a follow up investigation
on May 1,2024,and found the regulator to be in good working condition with no oil present.IGC has scheduled
a follow up investigation for July 2024. The oil found is being received from Williams Northwest Pipeline.
IGC has contacted Williams to discuss next steps for mitigating the oil.At this time,Williams is continuing to
investigate, in addition to re-evaluating their facility design and flow parameters.
Regulator Station 48371-RS-59992: The regulator was dissembled, cleaned, and reassembled onsite and
subsequently locked up properly.The primary regulator locked up as expected during the 2023 and 2022 annual
inspections. IGC is continuing to monitor the application of filtration devices for regulator stations that fail
lock-up two or more times in a three-year period.
Regulator Station 48371-RS-59976: This regulator station is scheduled to be rebuilt in 2025. The new station
design will include filtration ahead of the regulators. Rebuild is expected to be completed by end of year 2025.
Regulator Station 48371-RS-59977: The regulator was dissembled, cleaned, and reassembled onsite and
subsequently locked up properly.The primary regulator locked up as expected during the 2023 and 2022 annual
inspections. IGC is continuing to monitor the application of filtration devices for regulator stations that fail
lock-up two or more times in a three-year period.
Please contact Josh Sanders at(701)222-7773 with questions or comments.
Respectfully Submitted,
Pat Darras
Vice President,Engineering&Operations Services
Intermountain Gas Company