{"operation":"document","citation":"PLD22FR002","title":"Marathon Pipe Line LLC Pipeline Rupture and Crude Oil Release","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"2024-01-02","effective_on":"2022-03-11","summary":"Accident. in Edwardsville, IL, USA. on 2022-03-11. Marathon Pipe Line LLC. Rupture/release","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-pld22fr002.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-pld22fr002.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-pld22fr002","source_url":"https://www.ntsb.gov/investigations/Pages/PLD22FR002.aspx","body":"NTSB investigation PLD22FR002.\n\nEvent Type: Accident\n\nEvent Date: 2022-03-11\n\nEvent City: Edwardsville\n\nEvent State Or Region: IL\n\nEvent Country: USA\n\nPipeline Operator: Marathon Pipe Line LLC\n\nPipeline Type: Hazardous Liquid - Regulated\n\nAccident Type: Rupture/release\n\nCompletion Status: Completed\n\nReport Number: 2302\n\nReport Date: 2023-12-18\n\nProbable cause: The National Transportation Safety Board determines that the probable cause of the Edwardsville, Illinois, crude oil pipeline rupture was an overstress fracture of a girth weld from external loads caused by slope instability that had not been completely mitigated by Marathon before the accident.\n\nTier1Name: System operating\n\nTier2Name: Emergency shutoff\n\nTier1Name: System shutdown\n\nTier2Name: Emergency response\n\nTier1Name: System operating\n\nTier2Name: SCADA system event\n\nTier1Name: System operating\n\nTier2Name: Product leak/release\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipeline structure\n\nFinding Tier3Name: Joint/weld/seam\n\nFinding Modifier Name: Failure\n\nFinding Report Text: Pipeline - Pipeline structure - Joint/weld/seam - Failure\n\nFinding Tier1Name: Environment/Infrastructure\n\nFinding Tier2Name: Physical environment\n\nFinding Tier3Name: Soil\n\nFinding Modifier Name: Awareness of condition\n\nFinding Report Text: Environment/Infrastructure - Physical environment - Soil - Awareness of condition\n\nOfficial NTSB investigation data. NTSB findings determine probable cause and make safety recommendations; they do not adjudicate civil liability or regulatory violations.\n\nWhat Happened\nOn March 11, 2022, at 8:15:21 a.m. local time, a 22-inch diameter crude oil pipeline operated by Marathon Pipe Line, LLC ruptured at a girth weld in Edwardsville, Illinois, resulting in the release of about 3,500 barrels of crude oil, some of which entered Cahokia Creek. The rupture occurred at milepost 6.2 on the Woodpat pipeline, and no injuries or fatalities occurred as a result of the rupture.\n\nWhat We Found\nWe determined that the probable cause of the Edwardsville, Illinois, crude oil pipeline rupture was an overstress fracture of a girth weld from external loads caused by slope instability that had not been completely mitigated by Marathon before the accident.\n\nPIR-23-02\n<<<PAGE 1>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nIssued: December 18, 2023 Pipeline Investigation Report: PIR-23-02\nMarathon Pipe Line LLC Pipeline Rupture\nand Crude Oil Release\nEdwardsville, Illinois\nMarch 11, 2022\n1 Factual Information\n1.1 Accident Description\nOn March 11, 2022, at 8:15:21 a.m. local\ntime, a 22-inch diameter crude oil pipeline\noperated by Marathon Pipe Line, LLC\n(Marathon) ruptured at a girth weld in\nEdwardsville, Illinois, resulting in the release of\nabout 3,500 barrels of crude oil, some of which\nentered Cahokia Creek.1 (See figure 1.) The\nrupture occurred at milepost 6.2 on the\nWoodpat pipeline, the northernmost of three\nparallel pipelines sharing one right-of-way and\nthe closest to the creek.2 Figure 2 shows the\nalignment of Cahokia Creek, a tributary of the\nMississippi River. No injuries or fatalities\nFigure 1. Ruptured pipeline and Cahokia\nCreek. (Source: Marathon.)\n1 (a) Visit www.ntsb.gov to find additional information in the public docket for this NTSB accident\ninvestigation (case number PLD22FR002). Use the CAROL Query to search safety recommendations and\ninvestigations. (b) All times in this report are local time unless otherwise noted. (c) A girth weld joins two\npipes along their circumference.\n2 A milepost is a unit of measure used to define the location on a pipeline relative to a chosen starting\npoint in miles and fractions of miles.\n1\n\n<<<PAGE 2>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\noccurred as a result of the rupture. Marathon estimated the cost of property damage and\nemergency response to be $21,807,059.\nFigure 2. Cahokia Creek and Mississippi River.\nThe Woodpat pipeline is operated from Marathon’s Pipeline Operations Center\n(POC) in Findlay, Ohio, and is monitored and controlled by a supervisory control and\ndata acquisition system.3 The pipeline’s operating pressure at the time of failure was 467\npounds per square inch, gauge.\n4 Additional pipeline specifications are presented in\ntable 1.\n3 (a) Marathon’s POC monitors and controls the Marathon pipeline network 24 hours a day, 7 days a\nweek. (b) Supervisory control and data acquisition is a computer system used by operations centers to\ngather and analyze real-time data.\n4 The maximum operating pressure of the pipeline was 881 pounds per square inch, gauge.\n2\n\n<<<PAGE 3>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nTable 1. Woodpat pipeline specifications.\nPipeline Specification Value\nMaterial Steel\nGrade1 API-5L-X46\nLongitudinal Seam Weld Low-frequency electric resistance welded\nWall Thickness 0.344 inch\nManufacturer Youngstown Sheet & Tube\nYear Installed 1949\nFlow Direction West to east\nExternal Coating Type Coal tar enamel\nCathodic Protection Method Impressed current\n1 American Petroleum Institute 5LX defines specific grades of carbon steel pipeline, each with a minimum yield strength.\nThe higher the grade of the pipeline, the higher the strength of the steel used to manufacture that pipeline.\nAbout 8:15 a.m. on March 11, a rate-of-change alarm at Marathon’s POC showed\nlow suction pressure at the Roxana pump station, about 6 miles upstream of the rupture\nsite.\n5 A 55-mile segment of the Woodpat pipeline was isolated at 8:23:18 a.m.6 Field\npersonnel identified the origin of the rupture at the girth weld about 9:51 a.m., and the\nmainline block valves nearest the rupture location were closed about 10:07 a.m. to\nreduce the length of the isolated pipeline segment to about 27 miles.\n7\n1.2 Emergency Response\nMarathon deployed both internal and contracted oil spill removal organizations\n(OSROs), which brought oil containment and recovery equipment to control the release\nof oil and prevent it from traveling further downstream.8 The OSROs arrived at the\nrupture location by 10:50 a.m. on March 11.\nBy the evening of March 12, Marathon had established 10 oil spill containment\nsites along Cahokia Creek. Each of these sites were equipped with containment booms\n5 Pump stations are positioned at various points to move product along the pipeline. The suction side\nof a pump station is the lower-pressure input side.\n6 When a segment of pipeline is isolated, valves are closed to halt the flow of product.\n7 Mainline block valves are closed to isolate a pipeline segment.\n8 US Environmental Protection Agency. 2022. Polrep #1: Initial Marathon Pipeline Release Wood River\nto Patoka System.\n3\n\n<<<PAGE 4>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nand vacuum trucks.\n9 No impacts on downstream potable water sources on the\nMississippi River were documented. In the area of the rupture, the OSROs dug an\ninterceptor trench, contained the oil-contaminated soil, and removed pooled oil.10\nRecovered oil and contaminated water were temporarily stored in the vacuum trucks and\nin portable frac tanks stationed near the accident site.\n11 The OSROs took recovered\nliquids to Marathon’s Wood River Station to separate the oil from the creek water and to\nmeasure the recovery amounts.12\nBy April 1, 2022, the most severely contaminated soil had been removed from the\nexcavated area around the pipeline. In coordination with the Illinois Environmental\nProtection Agency, Marathon conducted soil sample testing to determine the extent of\nthe soil contamination.\n13 After testing and removal of contaminated soil, the pipeline was\nbackfilled with clean soil from an off-site source.\n1.3 Integrity Management\nIn the years leading up to the accident, Marathon assessed the threat of external\nloads on the Woodpat pipeline and took the below actions to address slope stability\nissues near the accident location.\n14\n9 (a) A containment boom is a temporary floating barrier used to contain an oil spill. (b) Vacuum trucks\nare used during a crude oil spill response to suction oil from surfaces.\n10 An interceptor trench acts as a catchment area to prevent contaminants from spreading.\n11 A frac tank is a large portable container used for temporary storage and separation of liquids such as\noil/water mixtures.\n12 Marathon reported that the total recovered amount of oil (free oil plus oil recovered from solid\nwaste) was 3,362 barrels.\n13 According to Marathon’s pipeline corridor soil sampling plan, soil sample testing was to be\nconducted until the oil was not detectable by sight or smell and photoionization detector readings were\nless than 50 parts per million. See Antea Group, 2022, Marathon Pipe Line LLC (MPL) Edwardsville\nResponse: Pipeline Corridor Soil Sampling Plan.\n14 External loads are loads transmitted to a pipeline from an external source; for example, those\nimposed by land movement.\n4\n\n<<<PAGE 5>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\n• August 21, 2012: A caliper/inertial measurement unit (IMU) assessment for\nmechanical damage and geometric anomalies was conducted.\n15\n• 2014: Concrete revetment mats were installed along the Cahokia Creek\nbank to protect the pipeline from erosion found in 2012.16\n• 2017: The revetment mats installed in 2014 were repaired, and additional\nmats and riprap were installed.17\n• January 5, 2018: A caliper/IMU assessment and bending strain analysis\nfound 18 areas with total bending strains of more than 0.125 percent—the\nhighest of which (0.34 percent) was near the rupture location.\n18\nRecommended mitigation efforts included in-situ strain monitoring, finite\nelement assessments, stress relief, further IMU assessments, pipeline\nmovement assessments, and pipeline replacement.19\n• July 7, 2021: An investigation, completed in response to the 2018 IMU\nassessment, indicated the left bank of Cahokia Creek was eroded, with\nevidence of slope instability including recent failures, scarps, and\ncracking.20 This investigation recommended increased monitoring of bank\ninstability, repeat depth-of-cover surveys, and additional reinforcement of\nthe bank. Based on this investigation, Marathon planned on conducting a\nbending strain and pipeline movement analysis in 2022, but that was not\ncompleted before the rupture occurred.\n15 An IMU assessment provides mapping information that is aligned with in-line inspection tools to\nlocate pipeline anomalies, features, and fittings. Data from an IMU assessment can be used to calculate\ncurvature along a pipeline. See General Electric, 2012, Excerpt from circumferential magnetic flux leakage\nfinal report.\n16 Concrete revetment mats consist of flexible concrete connected by fiber rope and are used for\nerosion control.\n17 Riprap is piled or stacked rocks used for erosion control.\n18 Bending strain, the change in pipeline length over original length caused by bending deformation, is\na common indicator of surrounding ground movement. See Rosen, 2019, Bending Strain Report: Marathon\nPetroleum, 22” Crude Oil Pipeline Roxanna to Patoka Woodpat, January 2018.\n19 A finite element assessment is the use of calculations, models, and simulations to predict and\nunderstand the behavior of an object or structure under various physical conditions.\n20 A scarp is a long, steep slope or cliff at the edge of a plateau or ridge, usually formed by erosion. See\nGeoMorphic Solutions, 2021, Strain Investigation Feature No. 25 WPAT 22-inch ROW 15 Strain Investigation\nStudy.\n5\n\n<<<PAGE 6>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\n• August 31, 2021: Another caliper/IMU assessment was completed. As of\nthe date of the accident, Marathon had not requested the strain report from\nthis assessment.\n1.4 Postaccident Assessment and Testing\n1.4.1 Geotechnical Assessment\nAfter the accident, a hydrotechnical analysis and slope stability assessment\ndetermined the earth movement at the rupture location was due to scouring in the creek\nthat was localized on the bank near the rupture location because of large, woody\ndebris.21 The assessment determined that the slope instability had continued after the\nrevetment mats and riprap were installed in 2014 and 2017.\n1.4.2 Metallurgical Testing\nWhile on scene, the National Transportation Safety Board (NTSB) observed\ncomplete circumferential separation at a girth weld at the rupture origin. The NTSB\nretained three sections of the Woodpat pipeline for metallurgical testing, which was\ncompleted by a third-party contractor directed by the NTSB.\n22 Inspections of the\nfractured girth weld revealed weld defects. Scanning electron microscopy was\nperformed on the fracture features of the girth weld, and those features exhibited\ncharacteristics consistent with overstress fracture.23\n1.4.3 GPS Survey\nThe day after the rupture, Marathon performed GPS surveys of the Woodpat\npipeline after the rupture. Figure 3 displays the results from the 2022 GPS surveys (green\ndotted line) with data from the IMUs conducted in 2018 (blue line) and 2021 (yellow\nline).\n21 Scouring is the removal of sediment from streambeds and streambanks by moving water. See\nGeosyntec, 2022, Memorandum Addressing Cause of Ground Movement Edwardsville, Illinois.\n22 One section came from the upstream side of the ruptured girth weld, including the upstream\nfracture face; one came from the downstream side, including the downstream fracture face; and one\nencompassed the next upstream girth weld, as an exemplar sample.\n23 Scanning electron microscopy is used to obtain high-resolution images of pipe surfaces, particularly\nof fracture surfaces, cracks, and other defects. See the NTSB Materials Laboratory Factual Report contained\nin the docket for this investigation for further details.\n6\n\n<<<PAGE 7>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nFigure 3. IMU data for Woodpat pipeline from 2018 and 2021 and 2022 postaccident GPS\nsurvey.\n1.4.4 Failure Analysis\nMarathon performed a failure analysis on the ruptured girth weld using the 2012,\n2018, and 2021 IMU assessments. As part of the failure analysis, Marathon completed a\nnumerical analysis using calibrated models established by the 2018 and 2021 IMU data\nand postaccident data to conduct a strain analysis and collect deviation-from-straight\nvalues.\n24 (See table 2.) The failure analysis indicated increased strain approximately 10\n24 Marathon did not calculate deviation-from-straight values at the time of the 2018 and 2021 IMU\nassessments.\n7\n\n<<<PAGE 8>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nfeet from the rupture location, with maximum total strain near the ruptured girth weld\nbetween 0.61 and 0.83 percent, and a deviation-from-straight value of just over 8 feet.\n25\nTable 2. Analysis of 2018 and 2021 IMU data and 2022 postaccident data.\nDate Maximum Combined\nBending Strain (%)\nBending Strain near Girth\nHorizontal Deviation from\nWeld (%)\nStraight1\n2018 0.34 0.02 5.7 feet\n2021 0.41 0.25 8 feet\n2022\n— 0.42 (estimated) 8.2 feet\n(time of rupture)\n1 These values were calculated in the postaccident numerical analysis.\n1.5 Postaccident Actions\n1.5.1 Marathon Pipeline LLC\nFollowing the rupture, Marathon conducted repairs and remediation activities. All\ngirth welds that had not been removed were examined using ultrasonic phased array\ntesting.\n26 Marathon also reevaluated its integrity management program and\nstandardized its method of geohazard threat identification, increased the use of in-line\ninspection to locate pipeline segments at risk from geohazards, expanded training for\ncontrollers, introduced technologies to assist employees with identifying geohazards,\nand contributed to research projects related to geohazards.\nOn March 14, 2022, Marathon sent the Pipeline and Hazardous Materials Safety\nAdministration (PHMSA) a commitment letter that included specific actions the company\nwould take in response to the rupture. This included performing fitness-for-service\ncalculations on the unearthed girth welds in the area of the rupture, reinforcing repairs to\ngirth welds that were exposed during postaccident response, conducting a geotechnical\nanalysis of the Cahokia Creek bank, completing site evaluations at locations on the\nWoodpat pipeline at which increased strain had been identified, summarizing events\nthat would trigger mitigative action, and completing a strain analysis from the 2021\n25 Maximum total strain is the maximum membrane strain within 10 feet of the girth weld plus the\nmaximum bending strain. Tensile strain capacity in this area was calculated to be 0.29 percent. See ADV\nIntegrity, Inc., 2023, Edwardsville Failure Analysis: Final Report.\n26 Ultrasonic phased array testing is often conducted in the field to determine if there are any defects in\nthe weld.\n8\n\n<<<PAGE 9>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nin-line inspection.27 Marathon also updated its geohazard susceptibility criteria and\napplied the criteria to all its pipelines.28\nOn March 15, 2022, Marathon installed about 60 feet of new pipe to replace the\nsections that had been removed and restarted the pipeline at 7:31 a.m.\nOn April 5, 2022, Marathon led an operator-to-operator information sharing\nwebinar, supported by the NTSB and PHMSA, for approximately 900 attendees, that\naddressed details of the incident, response, and initial lessons learned.\n1.5.2 Pipeline and Hazardous Materials Safety Administration\nPHMSA oversaw the implementation of the activities outlined by Marathon in its\ncommitment letter. In June 2022, PHMSA published an advisory bulletin reminding the\npipeline industry of the threat of earth movement and for pipeline operators to monitor\nand mitigate threats to pipeline integrity.29 In December 2022, PHMSA held a public\nmeeting reviewing recent geohazard failures including the Edwardsville rupture.\n2 Analysis\nIn this accident, a 22-inch diameter crude oil pipeline operated by Marathon\nruptured at a girth weld in Edwardsville, Illinois, resulting in the release of about 3,500\nbarrels of crude oil, some of which entered Cahokia Creek. The NTSB’s postaccident\nlaboratory testing of the ruptured sections of pipe showed that the girth weld had\nexperienced an overstress fracture. A review of records showed that Marathon had\ndocumented multiple indications of slope instability near the rupture location dating\nback to 2012, when an integrity assessment identified erosion along the Cahokia Creek\nbank. In 2014, Marathon installed concrete revetment mats to stabilize the bank.\n27 Fitness-for-service calculations are quantitative engineering evaluations, based on guidance\ncontained in American Petroleum Institute Recommended Practice 579, that assess the structural integrity\nof in-service components that may contain a flaw or damage or that may be operating under a specific\ncondition that might cause a failure.\n28 Marathon’s revised geohazard assessment frequency is once a year for pipeline segments with\nobserved geohazard issues, every 3 years for segments determined to be susceptible to geohazards, and\nevery 5 years for segments designated for monitoring only.\n29 For more information, see PHMSA Advisory Bulletin: Potential for Damage to Pipeline Facilities\nCaused by Earth Movement and Other Geological Hazards. Also cited in the advisory bulletin was a 2020\npipeline rupture in Hillsboro, Kentucky. See NTSB, 2022, Enbridge Inc. Natural Gas Pipeline Rupture,\nHillsboro, Kentucky, May 4, 2020, NTSB/PIR-22-01.\n9\n\n<<<PAGE 10>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nIn the years that followed, caliper/IMU assessments, strain analyses, and risk\nassessments indicated that the site of the rupture continued to experience slope\ninstability and that further reinforcement of the creek bank was necessary. In 2017,\nMarathon repaired previously installed revetment mats and added more mats and\nriprap. However, postaccident analyses reviewed and conducted by the NTSB showed\nthat these actions, as well as Marathon’s actions in 2014, were ineffective in completely\nprotecting the pipeline from external loads that were due to slope instability. Marathon\ndid not take further action to stabilize the creek bank after 2017.\nAlthough Marathon conducted IMU assessments in 2018 and 2021, it did not\ndeploy the strain monitoring recommended by the 2018 IMU assessment and bending\nstrain analysis, nor did it pursue finite element assessments, stress relief, pipeline\nmovement assessments, or pipeline replacement before the accident. Finite element\nassessments would have facilitated a more-accurate assessment of the strain on the\npipeline and would have allowed Marathon to better foresee the pending safety issues\nrelated to slope instability and deploy better strain mitigations that could have\nprevented the rupture.\nFurther, a 2021 strain investigation, also based on the 2018 IMU data, indicated\nthat slope instability was still present and recommended monitoring and bank\nreinforcement, but Marathon did not do this by the time of the accident. Marathon had\nplanned to conduct a bending strain and pipeline movement analysis in 2022, but the\nrupture preceded such action.\nAs a result of this accident, Marathon revised its total bending strain action limits\nto be more stringent, facilitating additional site investigations and remediation projects\nfor locations that could be at risk of geohazard-related damage. The company also\namended its geohazard assessment frequency, began collecting deviation-from-straight\nvalues to analyze bending strain features, expanded methods to proactively identify\ngeohazard threats, and formalized the protocol to calculate total strain demand on\npipelines from strain features.\nAfter the accident, PHMSA issued an advisory bulletin on damage to pipeline\nfacilities from earth movement and conducted a public meeting to discuss the\nprevention of geohazard accidents. Marathon conducted a widely attended information-\nsharing event on lessons learned from the rupture, supported by the NTSB and PHMSA.\n3 Probable Cause\nThe National Transportation Safety Board determines that the probable cause of\nthe Edwardsville, Illinois, crude oil pipeline rupture was an overstress fracture of a girth\nweld from external loads caused by slope instability that had not been completely\nmitigated by Marathon before the accident.\n10\n\n<<<PAGE 11>>>\n\nMarathon Pipe Line LLC Pipeline Rupture and Crude Oil Release\nPIR-23-02\nThe NTSB is an independent federal agency charged by Congress with\ninvestigating every civil aviation accident in the United States and significant events in the\nother modes of transportation—railroad, transit, highway, marine, pipeline, and\ncommercial space. We determine the probable causes of the accidents and events we\ninvestigate and issue safety recommendations aimed at preventing future occurrences. In\naddition, we conduct transportation safety research studies and offer information and\nother assistance to family members and survivors for each accident or event we\ninvestigate. We also serve as the appellate authority for enforcement actions involving\naviation and mariner certificates issued by the Federal Aviation Administration (FAA) and\nUS Coast Guard, and we adjudicate appeals of civil penalty actions taken by the FAA.\nThe NTSB does not assign fault or blame for an accident or incident; rather, as\nspecified by NTSB regulation, “accident/incident investigations are fact-finding\nproceedings with no formal issues and no adverse parties … and are not conducted for\nthe purpose of determining the rights or liabilities of any person” (Title 49 Code of\nFederal Regulations section 831.4). Assignment of fault or legal liability is not relevant to\nthe NTSB’s statutory mission to improve transportation safety by investigating accidents\nand incidents and issuing safety recommendations. In addition, statutory language\nprohibits the admission into evidence or use of any part of an NTSB report related to an\naccident in a civil action for damages resulting from a matter mentioned in the report\n(Title 49 United States Code section 1154(b)).\nFor more detailed background information on this report, visit the NTSB Case\nAnalysis and Reporting Online (CAROL) website and search for NTSB accident ID\nPLD22FR002. Recent publications are available in their entirety on the NTSB website.\nOther information about available publications also may be obtained from the website or\nby contacting —\nNational Transportation Safety Board\nRecords Management Division, CIO-40\n490 L’Enfant Plaza, SW\nWashington, DC 20594\n(800) 877-6799 or (202) 314-6551\n11","truncated":false,"body_characters":24639}