{"operation":"document","citation":"CPF 32026002CAO","title":"NORTHERN NATURAL GAS CO — Corrective Action Order","source_type":"enforcement","agency":"Pipeline and Hazardous Materials Safety Administration","status":"current","official":true,"published_on":"2026-01-17","effective_on":null,"summary":"OPEN corrective action order.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-enforcement-32026002cao.json","markdown":"https://regulus.evalyn.ai/document/phmsa-enforcement-32026002cao.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-enforcement-32026002cao","source_url":"https://primis.phmsa.dot.gov/enforcement-data/case/32026002CAO","body":"Corrective Action Order involving NORTHERN NATURAL GAS CO. The dataset does not identify a cited regulation for this case. The case was opened on 2026-01-17 and is reported as open. Open the official case record for notices, responses, orders, and the latest status.\n\nOfficial case documents:\n\n32026002CAO_Corrective Action Order_01172026_(26-362536).pdf: https://primis.phmsa.dot.gov/enforcement-documents/32026002CAO/32026002CAO_Corrective%20Action%20Order_01172026_(26-362536).pdf\n\n32026002CAO_Corrective Action Order_01172026_(26-362536)_text.pdf: https://primis.phmsa.dot.gov/enforcement-documents/32026002CAO/32026002CAO_Corrective%20Action%20Order_01172026_(26-362536)_text.pdf\n\n32026002CAO_Corrective Action Order_01172026_(26-362536)_text.pdf\n\nU.S. Department\nof Transportation\nPipeline and Hazardous\nMaterials Safety\nAdministration\n1200 New Jersey Avenue, SE\nWashington, DC 20590\nJanuary 17, 2026\nVIA ELECTRONIC MAIL TO: brian.mundt@nngco.com\nBrian Mundt\nPresident/CEO\nNorthern Natural Gas Company\n1111 South 103rd Street\nOmaha, Nebraska 68124\nRe: CPF No. 3-2026-002-CAO\nDear Mr. Mundt,\nEnclosed please find a Corrective Action Order (CAO or Order) issued by the Pipeline and\nHazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS). The CAO\nrequires Northern Natural Gas Company (NNG) to take certain corrective actions with respect to\nthe pipeline failure that occurred on January 16, 2026, on the 20-inch M440B pipeline\napproximately two miles west of Willow River, Minnesota.\nService of the CAO by electronic mail is effective upon the date of transmission and\nacknowledgment of receipt as provided under 49 CFR § 190.5. The terms and conditions of this\nOrder are effective upon completion of service.\nSincerely,\nLinda Daugherty\nActing Associate Administrator\nfor Pipeline Safety\nEnclosure: CAO\ncc: Mr. David Barrett, Acting Director, Central Region, OPS, PHMSA\nCONFIRMATION OF RECEIPT REQUESTED\n\n\n\nU.S. DEPARTMENT OF TRANSPORTATION\nPIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION\nOFFICE OF PIPELINE SAFETY\nWASHINGTON, D.C. 20590\n____________________________________\n)\nIn the Matter of )\n)\nNorthern Natural Gas Company, ) CPF No. 3-2026-002-CAO\n)\nRespondent. )\n)\n____________________________________)\nCORRECTIVE ACTION ORDER\nPurpose and Background\nThe Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline\nSafety (OPS), is issuing this Corrective Action Order (CAO or Order) pursuant to the authority\nprovided in 49 U.S.C. § 60112. The CAO requires Northern Natural Gas Company (NNG or\nRespondent), a subsidiary of Berkshire Hathaway Energy,\n1 to take certain necessary corrective\nactions to protect the public, property, and the environment from the potential hazards associated\nwith the continued operation of the M440B pipeline. The M440B pipeline is an 86-mile, 20-inch\ndiameter interstate natural gas pipeline system that extends from the North Branch Compressor\nStation to the Carlton Compressor Station in Minnesota.\nOn January 16, 2026, at approximately 2:00 pm CDT, the M440B pipeline ruptured at a location\napproximately two miles west of Willow River, Minnesota (Failure). The Failure resulted in the\nrelease of approximately 63 MMcf of natural gas in a rural area. The released natural gas caught\nfire in two locations approximately 1,000 feet apart. NNG responded by shutting down the\npipeline and closing valves necessary to isolate the site of the Failure. Three nearby towns lost\nnatural gas service following the Failure with approximately 830 customers being affected.\nPursuant to 49 U.S.C. § 60117, PHMSA has initiated an investigation of the Failure. The\npreliminary findings of PHMSA’s ongoing investigation are as follows:\nPreliminary Findings\nJanuary 16, 2026 Incident\n1 NNG operates the largest interstate natural gas pipeline system in the United States, with 14,300 miles of pipe\nextending from the Permian Basin in Texas to the Upper Peninsula of Michigan. NNG accesses supply from every\nmajor Mid-Continent basin, as well as the Permian, Rocky Mountain and Western Canadian basins. This supply is\nultimately delivered to end-use customers in Minnesota, Iowa, Nebraska, South Dakota, Wisconsin, Illinois, and the\nUpper Peninsula of Michigan. NNG also operates three underground natural gas storage (UNGS) facilities and two\nliquefied natural gas (LNG) peaking units.\n\n\n\n• On January 16, 2026, at approximately 2:00 pm CDT, the M440B pipeline ruptured\napproximately 2 miles west of Willow River, MN. The released natural gas caught fire in\ntwo locations approximately 1,000 feet apart at each end of the failed pipe.\n• The Respondent initiated efforts to contain the release by closing valves to isolate the\nFailure.\n• The Failure occurred in a rural area and did not result in any fatalities, or injuries. Three\nhomes were evacuated, and the residents were allowed to return home later in the day.\n• NNG notified the National Response Center (NRC) of the Failure on January 16, 2026, at\napproximately 3:30 pm (NRC Incident Report # 1452887).\n• PHMSA and the Minnesota Office of Pipeline Safety (MNOPS) launched an onsite\ninvestigation and investigators arrived at the site of the Failure on January 16, 2026.\n• PHMSA and MNOPS investigators at the site saw the ruptured pipeline and observed that\napproximately 1,000 feet of pipe had self-excavated during the rupture.\n• The pipe at the Failure location is 20-inch diameter pipe manufactured in 1959 with API\n5L X52 low frequency electric resistance welded (LF-ERW) longitudinal seam\nmanufactured by Youngstown. LF-ERW pipe of this vintage is known to be susceptible\nto integrity issues.\n• In 2021, NNG ran inline inspection (ILI) tools through the M440B pipeline at the\nlocation of the Failure, including magnetic flux leakage (MFL), circumferential MFL,\nmapping tool, and a pipe grade tool.\n• The maximum allowable operating pressure (MAOP) of the pipe at the Failure site is\n1,050 pounds per square inch gauge (psig). The operating pressure at the time of the\nFailure was approximately 1,016 psig.\n• NNG indicated to PHMSA and MNOPS investigators that the Failure resulted in the\nestimated release of approximately 63 MMcf of natural gas.\n• Three nearby towns lost natural gas service following the Failure with approximately 830\ncustomers being affected\nDetermination of Necessity for Corrective Action Order and Right to Hearing\nSection 60112 of title 49, United States Code, authorizes PHMSA to determine that a pipeline\nfacility is or would be hazardous to life, property, or the environment and if there is a likelihood\nof serious harm, to expeditiously order the operator of the facility to take necessary corrective\naction, including suspended or restricted use of the facility, physical inspection, testing, repair,\n\n\n\nreplacement, or other appropriate action. An order issued expeditiously must provide an\nopportunity for a hearing as soon as practicable after the order is issued.\nIn deciding whether to issue an order, PHMSA must consider the following, if relevant: (1) the\ncharacteristics of the pipe and other equipment used in the pipeline facility, including the age,\nmanufacture, physical properties, and method of manufacturing, constructing, or assembling the\nequipment; (2) the nature of the material the pipeline facility transports, the corrosive and\ndeteriorative qualities of the material, the sequence in which the material is transported, and the\npressure required for transporting the material; (3) the aspects of the area in which the pipeline\nfacility is located, including climatic and geologic conditions and soil characteristics; (4) the\nproximity of the area in which the facility is located to environmentally sensitive areas; (5) the\npopulation density and population and growth patterns of the area in which the pipeline facility is\nlocated; (6) any recommendation of the National Transportation Safety Board made under\nanother law; and (7) any other factors PHMSA may consider as appropriate.\nAfter evaluating the foregoing preliminary findings of fact, and having considered the\ncharacteristics of the pipeline, the nature of the failure; the hazardous nature of the material\ntransported; the existing and potential additional impacts to property, the environment, and\nwildlife; it is hereby determined that continued operation of the Affected Segment of the NNG\nM440B pipeline, as defined below, without corrective measures is or would be hazardous to life,\nproperty, or the environment, and that failure to issue this Order expeditiously would result in the\nlikelihood of serious harm.\nAccordingly, this Order mandating immediate corrective action is issued expeditiously without\nprior notice and opportunity for a hearing. The terms and conditions of this Order are effective\nupon completion of service.\nWithin 10 days of receipt of this Order, Respondent may request a hearing, to be held as soon as\npracticable, by notifying the Associate Administrator for Pipeline Safety in writing, with a copy\nto the Director, PHMSA, OPS Central Region. If a hearing is requested, it will be held in\naccordance with 49 CFR § 190.211.\nAfter receiving and analyzing additional data in the course of this investigation, PHMSA may\nidentify other corrective measures that need to be taken. Respondent will be notified of any\nadditional measures required and, if appropriate, PHMSA will consider a further amended order.\nTo the extent consistent with safety, Respondent will be afforded notice and an opportunity for a\nhearing prior to the imposition of any additional corrective measures.\nDefinitions\nAffected Segment – The “Affected Segment” means the 20-inch diameter, M440B pipeline from\nthe North Branch Compressor Station (M.P. 0) to Carlton Compressor Station (MP 85.67).\nIsolated Segment – The “Isolated Segment” means the 20-inch diameter M440B pipeline from\nMP 43 to MP 57.\nFailure Segment – The Failure Segment means the approximately 1,000 feet of pipe (MP 53.88\nto 54.6) that ruptured on January 16, 2026.\n\n\n\nDirector – The “Director” means the Director, PHMSA, OPS Central Region.\n1. Restart Plan. Prior to resuming operation of the Isolated Segment, NNG must develop and\nsubmit a written Restart Plan to the Director for prior approval. The Restart Plan may be\nsubmitted in incremental stages.\na. The Restart Plan must include a Repair Plan for the Director’s approval. The Repair\nPlan may include short-term provisions to operate portions of the Isolated Segment at\nreduced pressure outside the limits of the Failure Segment to provide natural gas\nservice to local communities supplied within the Isolated Segment while completing\nrepairs within the Failure Segment. Any short-term operating provisions within the\nRepair Plan must specify pressure limits within the Isolated Segment while completing\nrepairs.\nb. The Director may approve the Restart Plan incrementally, including the Repair Plan,\nwithout approving the entire plan.\nc. Once approved by the Director, the Restart Plan will be incorporated by reference into\nthis Order.\nd. The Restart Plan must provide for adequate patrolling and sufficient surveillance of\nthe Isolated Segment during the restart process to ensure that no leaks are present\nwhen operation of the line resumes.\ne. The Restart Plan must specify a day-light restart and include advance communications\nwith local emergency response officials.\n2. Operating Pressure Restriction. NNG must reduce and maintain a twenty percent (20%)\npressure reduction in the actual operating pressure along the entire length of the Affected\nSegment, such that the operating pressure along the Affected Segment will not exceed\neighty percent (80%) of the actual operating pressure in effect immediately prior to the\nfailure on January 16, 2026.\na. This pressure restriction must remain in effect until written approval to increase the\npressure or return the pipeline to its pre-failure operating pressure is obtained from the\nDirector.\nb. Within 10 days of issuance of the Order, NNG must provide the Director the actual\noperating pressures of each compressor station and each main line pressure regulating\nstation on the Affected Segment at the time of failure and the reduced pressure\nrestriction set-points at these same locations.\nc. This pressure restriction requires any relevant remote or local alarm limits, software\nprogramming set-points or control points, and mechanical over-pressure devices to be\nadjusted accordingly.\nd. When determining the pressure restriction set-points, NNG must take into account any\nin-line inspection (ILI) features or anomalies present in the Affected Segment to\nprovide for continued safe operation while further corrective actions are completed.\ne. NNG must review the pressure restriction monthly by analyzing the operating pressure\ndata. NNG must take into account any ILI features or anomalies present in the\nAffected Segment and immediately reduce the operating pressure to maintain the safe\noperations of the Affected Segment, if warranted by the monthly review. NNG must\nsubmit the results of the monthly review to the Director. The results must include, at a\nminimum, the current discharge set-points (including any additional pressure\nreductions), and any pressure exceedance at discharge set-points.\n\n\n\nf. NNG may request approval from the Director to increase the operating pressure on\nindividual segments on the Affected Pipeline based on an engineering analysis or other\njustification that the segment does not pose a safety risk.\n3. Mechanical and Metallurgical Testing. Within 45 days of receipt of this Order, NNG\nmust complete mechanical and metallurgical testing and failure analysis of the failed pipe,\nincluding an analysis of soil samples and any foreign materials. Complete the testing and\nanalysis as follows:\na. Document the chain-of-custody when handling and transporting the failed pipe section\nand other evidence from the failure site.\nb. Within 10 days of receipt of this Order, develop and submit the testing protocol and\nthe proposed testing laboratory to the Director for prior approval.\nc. Prior to beginning the mechanical and metallurgical testing, provide the Director with\nthe scheduled date, time, and location of the testing to allow for an OPS representative\nto witness the testing.\nd. Ensure the testing laboratory distributes all reports (whether draft or final) in their\nentirety to the Director at the same time they are made available to NNG.\n4. Root Cause Failure Analysis. Within 90 days following receipt of this Order, NNG must\ncomplete a root cause failure analysis (RCFA) and submit a final report of this RCFA to\nthe Director. The RCFA must be supplemented/facilitated by an independent third-party\nacceptable to the Director and must document the decision making process and all factors\ncontributing to the failure. The final report must include findings, and any lessons learned\nand whether the findings and any lessons learned are applicable to other locations within\nNNG’s pipeline system. The independent third-party must distribute all RCFA reports\n(whether draft or final) in their entirety to the Director at the same time they are made\navailable to NNG provide all versions of the RCFA\n5. Remedial Work Plan (RWP).\na. Within 120 days following receipt of this Order, NNG must submit a Remedial Work\nPlan (RWP) to the Director for approval.\nb. The Director may approve the RWP incrementally without approving the entire RWP.\nc. Once approved by the Director, the RWP will be incorporated by reference into this\nOrder.\nd. The RWP must specify the tests, inspections, assessments, evaluations, and remedial\nmeasures NNG will use to verify the integrity of the Affected Segment. It must\naddress all known or suspected factors and causes of the January 16, 2026 failure.\nNNG must consider both the risk of another failure and the consequence of another\nfailure to develop a prioritized schedule for RWP related work along the Affected\nSegment.\ne. The RWP must include a procedure or process to:\ni. Identify pipe in the Affected Segment with characteristics similar to the contributing\nfactors identified for the January 16, 2026 failure.\nii. Gather all data necessary to review the failure history (in service and pressure test\nfailures) of the Affected Segment and to prepare a written report containing all the\navailable information such as the locations, dates, and causes of leaks and failures.\niii. Integrate the results of the metallurgical testing, RCFA, and other corrective actions\nrequired by this Order with all relevant pre-existing operational and assessment data\nfor the Affected Segment. Pre-existing operational data includes, but is not limited\n\n\n\nto, construction, operations, maintenance, testing, repairs, prior metallurgical\nanalyses, and any third party consultation information. Pre-existing assessment data\nincludes, but is not limited to, ILI tool runs, hydrostatic pressure testing, direct\nassessments, close interval surveys, and DCVG/ACVG surveys.\niv. Determine if conditions similar to those contributing to the failure on January 16,\n2026, are likely to exist elsewhere on the Affected Segment.\nv. Conduct additional field tests, inspections, assessments, and/or evaluations to\ndetermine whether, and to what extent, the conditions associated with the failure on\nJanuary 16, 2026, and other failures from the failure history (see [(e)(ii)] above) or\nany other integrity threats are present elsewhere on the Affected Segment. At a\nminimum, this process must consider all failure causes and specify the use of one or\nmore of the following:\n1) ILI tools that are technically appropriate for assessing the pipeline system based\non the cause of failure on January 16, 2026, and that can reliably detect and identify\nanomalies,\n2) Hydrostatic pressure testing,\n3) Close-interval surveys,\n4) Cathodic protection surveys, to include interference surveys in coordination with\nother utilities (e.g. underground utilities, overhead power lines, etc.) in the area,\n5) Coating surveys,\n6) Stress corrosion cracking surveys,\n7) Selective seam corrosion surveys; and,\n8) Other tests, inspections, assessments, and evaluations appropriate for the failure\ncauses.\nNote: NNG may use the results of previous tests, inspections, assessments, and\nevaluations if approved by the Director, provided the results of the tests, inspections,\nassessments, and evaluations are analyzed with regard to the factors known or\nsuspected to have caused the January 16, 2026 failure.\nvi. Describe the inspection and repair criteria NNG will use to prioritize, excavate,\nevaluate, and repair anomalies, imperfections, and other identified integrity threats.\nInclude a description of how any defects will be graded and a schedule for repairs or\nreplacement.\nvii. Describe the methods NNG will use to repair, replace, or take other corrective\nmeasures to remediate the conditions associated with the pipeline failure on January\n16, 2026, and to address other known integrity threats along the Affected Segment.\nThe repair, replacement, or other corrective measures must meet the criteria\nspecified in [1(d)(vi)] above.\nviii. Implement continuing long-term periodic testing and integrity verification measures\nto ensure the ongoing safe operation of the Affected Segment considering the results\nof the analyses, inspections, evaluations, and corrective measures undertaken\npursuant to the Order.\nf. Include a proposed schedule for completion of the RWP.\ng. NNG must revise the RWP as necessary to incorporate new information obtained\nduring the failure investigation and remedial activities, to incorporate the results of\nactions undertaken pursuant to this Order, and/or to incorporate modifications required\nby the Director.\ni. Submit any plan revisions to the Director for prior approval.\nii. The Director may approve plan revisions incrementally.\n\n\n\niii. Any and all revisions to the RWP after it has been approved and incorporated by\nreference into this Order will be fully described and documented in the CAO\nDocumentation Report (CDR).\nh. Implement the RWP as it is approved by the Director, including any revisions to the\nplan.\n6. CAO Documentation Report (CDR). NNG must create and revise, as necessary, a CAO\nDocumentation Report (CDR). When NNG has concluded all the items in this Order it will\nsubmit the final CDR in its entirety to the Director. This will allow the Director to complete\na thorough review of all actions taken by NNG with regards to this Order prior to\napproving the closure of this Order. The intent is for the CDR to summarize all activities\nand documentation associated with this Order in one document.\na. The Director may approve the CDR incrementally without approving the entire CDR.\nb. Once approved by the Director, the CDR will be incorporated by reference into this\nOrder.\nc. The CDR must include but not be limited to:\ni. Table of Contents;\nii. Summary of the pipeline failure of January 16, 2026, and the response activities;\niii. Summary of pipe data/properties and all prior assessments of the Affected Segment;\niv. Summary of all tests, inspections, assessments, evaluations, and analysis required by\nthe Order;\nv. Summary of the Mechanical and Metallurgical Testing as required by the Order;\nvi. Summary of the RCFA with all root causes as required by the Order;\nvii. Documentation of all actions taken by NNG to implement the RWP, the results of\nthose actions, and the inspection and repair criteria used;\nviii. Documentation of any revisions to the RWP including those necessary to incorporate\nthe results of actions undertaken pursuant to this Order and whenever necessary to\nincorporate new information obtained during the failure investigation and remedial\nactivities;\nix. Lessons learned while completing this Order;\nx. A path forward describing specific actions NNG will take on its entire pipeline\nsystem as a result of the lessons learned from work on this Order; and\nxi. Appendices (if required).\nOther Requirements:\n7. Approvals. With respect to each submission under this Order that requires the approval of\nthe Director, the Director may: (a) approve, in whole or part, the submission; (b) approve\nthe submission on specified conditions; (c) modify the submission to cure any\ndeficiencies; (d) disapprove in whole or in part, the submission, directing that Respondent\nmodify the submission, or (e) any combination of the above. In the event of approval,\napproval upon conditions, or modification by the Director, Respondent shall proceed to\ntake all action required by the submission as approved or modified by the Director. If the\nDirector disapproves all or any portion of the submission, Respondent must correct all\ndeficiencies within the time specified by the Director and resubmit it for approval.\n8. Extensions of Time. The Director may grant an extension of time for compliance with any\nof the terms of this Order upon a written request timely submitted demonstrating good\ncause for an extension.\n\n\n\n9. Reporting. Submit quarterly reports to the Director that: (1) include all available data and\nresults of the testing and evaluations required by this Order; and (2) describe the progress\nof the repairs or other remedial actions being undertaken. The first quarterly report is due\non April 30, 2026, covering the period through March 31, 2026. The Director may change\nthe interval for the submission of these reports.\n10. Documentation of the Costs. It is requested that Respondent maintain documentation of\nthe costs associated with implementation of this CAO. Include in each monthly report\nsubmitted, the to-date total costs associated with: (1) preparation and revision of\nprocedures, studies, and analyses; (2) physical changes to pipeline infrastructure, including\nrepairs, replacements, and other modifications; and (3) environmental remediation, if\napplicable.\nBe advised that all material submitted in response to this enforcement action is subject to being\nmade publicly available. If you believe that any portion of your responsive material qualifies\nfor confidential treatment under 5 U.S.C. § 552(b), along with the complete original document\nyou must provide a second copy of the document with the portions you believe qualify for\nconfidential treatment redacted and an explanation of why you believe the redacted information\nqualifies for confidential treatment under 5 U.S.C. § 552(b).\nIn your correspondence on this matter, please refer to “CPF No. 3-2026-002-CAO” and for\neach document you submit, please provide a copy in electronic format whenever possible. The\nactions required by this Order are in addition to and do not waive any requirements that apply\nto Respondent’s pipeline system under 49 CFR Parts 190 through 199, under any other order\nissued to Respondent under authority of 49 U.S.C. Chapter 601, or under any other provision of\nfederal or state law.\nRespondent may appeal any decision of the Director to the Associate Administrator for\nPipeline Safety. Decisions of the Associate Administrator shall be final.\nFailure to comply with this Order may result in the assessment of civil penalties and in referral\nto the Attorney General for appropriate relief in United States District Court pursuant to 49\nU.S.C. § 60120.\nThe terms and conditions of this Order are effective upon service in accordance with\n49 CFR § 190.5.\nJanuary 17, 2026\n_____________________________ __________________________\nLinda Daugherty Date Issued\nActing Associate Administrator\nfor Pipeline Safety","truncated":false,"body_characters":25461}