{"operation":"document","citation":"PLD18LR001","title":"TransCanada Corporation Pipeline (Keystone Pipeline) Rupture","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"2021-05-18","effective_on":"2017-11-16","summary":"Accident. in Amherst, SD, USA. on 2017-11-16. Keystone Pipeline. Rupture","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-pld18lr001.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-pld18lr001.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-pld18lr001","source_url":"https://www.ntsb.gov/investigations/Pages/PLD18LR001.aspx","body":"NTSB investigation PLD18LR001.\n\nEvent Type: Accident\n\nEvent Date: 2017-11-16\n\nEvent City: Amherst\n\nEvent State Or Region: SD\n\nEvent Country: USA\n\nPipeline Operator: Keystone Pipeline\n\nPipeline Type: Hazardous Liquid - Regulated\n\nAccident Type: Rupture\n\nCompletion Status: Completed\n\nReport Number: PAB1801\n\nReport Date: 2018-07-05\n\nProbable cause: The NTSB determines that the probable cause of the failure of the Keystone Pipeline was a fatigue crack, likely originating from mechanical damage to the pipe exterior by a metal-tracked vehicle during pipeline installation, that grew and extended in-service to a critical size, resulting in the rupture of the pipeline.\n\nTier1Name: Pigging\n\nTier2Name: Pressure/flow/temp event\n\nTier1Name: System operating, changing flow/pressure\n\nTier2Name: Pipe structural malfunction/failure\n\nTier1Name: System operating\n\nTier2Name: Pressure/flow/temp event\n\nTier1Name: System shutdown\n\nTier2Name: Emergency shutoff\n\nTier1Name: Emergency response\n\nTier2Name: Emergency response\n\nTier1Name: System operating\n\nTier2Name: Product leak/release\n\nTier1Name: System operating\n\nTier2Name: Inspection event\n\nTier1Name: System not operating\n\nTier2Name: External/third-party damage\n\nFinding Tier1Name: Personnel\n\nFinding Tier2Name: Action/decision\n\nFinding Tier3Name: Action\n\nFinding Modifier Name: Other/unknown\n\nFinding Report Text: Personnel - Action/decision - Action - Other/unknown\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipeline handling/service\n\nFinding Tier3Name: Maintenance/inspection\n\nFinding Modifier Name: Not inspected\n\nFinding Report Text: Pipeline - Pipeline handling/service - Maintenance/inspection - Not inspected\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipeline structure\n\nFinding Tier3Name: Pipe\n\nFinding Modifier Name: Fatigue/wear/corrosion\n\nFinding Report Text: Pipeline - Pipeline structure - Pipe - Fatigue/wear/corrosion\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipeline structure\n\nFinding Tier3Name: Pipe\n\nFinding Modifier Name: Damaged/degraded\n\nFinding Report Text: Pipeline - Pipeline structure - Pipe - Damaged/degraded\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 November 16, 2017, at 4:34 a.m. mountain daylight time, a TransCanada Corporation, Keystone Pipeline (Keystone) ruptured near Amherst, South Dakota, between the Ludden, North Dakota, (Ludden) and Ferney, South Dakota, (Ferney) pump stations. Keystone's Operational Control Center (OCC), in Calgary, Alberta, Canada, was monitoring Keystone's Supervisory Control and Data Acquisition system that detected the leak and shut down the pipeline. Keystone's field staff traveled to the indicated leak location, confirmed that the pipeline had ruptured, and initiated their spill response plan. The approximate spill area was comprised of about 5,000 barrels of crude oil.\n\nWhat We Found\nWe determined that the probable cause of the failure of the Keystone Pipeline was a fatigue crack, likely originating from mechanical damage to the pipe exterior by a metal-tracked vehicle during pipeline installation, that grew and extended in-service to a critical size, resulting in the rupture of the pipeline.\n\nPAB-18-01\n<<<PAGE 1>>>\n\nNational Transportation Safety Board\nPipeline Accident Brief\nTransCanada Corporation Pipeline (Keystone Pipeline)\nRupture\nAmherst, South Dakota\nThe Accident\nOn November 16, 2017, at 4:34 a.m. mountain daylight time, a TransCanada Corporation,\nKeystone Pipeline (Keystone) ruptured near Amherst, South Dakota, between the Ludden, North\nDakota, (Ludden) and Ferney, South Dakota, (Ferney) pump stations. Keystone’s Operational\nControl Center (OCC), in Calgary, Alberta, Canada, was monitoring Keystone’s Supervisory\nControl and Data Acquisition system that detected the leak and shut down the pipeline. Keystone’s\nfield staff traveled to the indicated leak location, confirmed that the pipeline had ruptured, and\ninitiated their spill response plan. The approximate spill area was comprised of about 5,000 barrels\nof crude oil. (See figure 1.)\nFigure 1. Accident scene in Amherst, South Dakota taken on November 16, 2017.\n(source: https://twitter.com/TransCanada)\nWhen notified about the accident, the National Transportation Safety Board (NTSB)\ncoordinated with the Pipeline and Hazardous Materials Safety Administration (PHMSA) to\nconduct a metallurgical examination of the pipe to establish a probable cause of the pipeline\nNTSB/PAB-18/01\n\n<<<PAGE 2>>>\n\nTransCanada Corporation Pipeline (Keystone Pipeline) Rupture\nrupture. As part of its comprehensive investigation of Keystone’s operations and practices leading\nup to the pipeline rupture, PHMSA provided oversight of Keystone’s excavation, removal, and\nshipment of the failed pipe section to the NTSB laboratory in Washington, DC.\n1\nAt the time of the pipeline rupture, Keystone was conducting an in-line inspection (ILI)\nusing a cleaning tool (pig) and an acoustic leak detection tool (SmartBall).\n2 Prior to the rupture,\nboth the cleaning pig and the SmartBall leak detection tool had traveled past the nearest block\nvalve downstream of the rupture location (Ludden + 28). The tools were run in a light-sweet blend\nbatch of crude oil, followed by a batch of sour crude. In preparation for the tools to bypass the next\ndownstream pump station in Ferney, a bypass operation of the Ferney pump station was initiated\nat 5:03 a.m. The bypass of the Ferney pump station was fully executed at 5:24 a.m. The pump\nstation bypass resulted in a gradual and anticipated pressure increase at the discharge of the\nupstream station in Ludden. The pressure records from Ludden indicated that the pressure had\nincreased from 1,170 pounds per square inch gage (psig) to 1,352 psig when the rupture occurred.\nSince the pipeline installation, no ILI tools for detecting cracks had been used.\nThe first indication of the pipeline rupture occurred at 5:33 a.m., when an abrupt drop in\ndischarge pressure and a corresponding increase in flow rate were observed at the Ludden pump\nstation. In addition, at 5:34 a.m., a corresponding pressure drop was observed at the Ferney pump\nstation. The controller at Keystone’s OCC initiated an emergency shutdown of the pipeline at\n5:36 a.m. and commenced isolation of the pipeline. By 5:45 a.m., the failure location had been\nisolated by using remotely operated valves. Keystone personnel were dispatched to investigate the\npipeline right-of-way for signs of a release and confirmed oil on the ground about 9:15 a.m.\nKeystone personnel then notified Marshall County emergency services; the Britton Fire\nDepartment and Marshall County Sheriff responded within minutes of notification. The incident\ncommander established and maintained a 1-mile safety zone during the response.\nThe Pipeline System\nThe Keystone Pipeline originates in Hardisty, Alberta, Canada, and delivers crude oil to\nterminals in Patoka, Illinois, and Cushing, Oklahoma. The rupture occurred downstream of the\nLudden pump station, at milepost 234.2, in Marshall County, South Dakota. The pipe at the rupture\nlocation was constructed during the fall of 2008 and was commissioned in 2010. The ruptured pipe\nwas 30 inches in diameter with a 0.386-inch wall thickness and was manufactured by Berg Pipe to\nAmerican Petroleum Institute Specification 5L grade X-70 product specification level 2, using a\ndouble submerged arc-welded (DSAW) longitudinal weld seam and fusion bonded epoxy (FBE)\ncoating. The pipeline was constructed and operated under a special permit, which allowed\noperation at pressures up to 80 percent of specified minimum yield strength (SMYS).3\nWhen the pipe was excavated, concrete weights installed during construction were found\nat the rupture location. The ruptured pipe piece along with a portion of one concrete weight were\n1 As of the date of this report, PHMSA has not yet completed its investigation.\n2 Registered trademark of Xylem Inc. Edmonton, Alberta, Canada.\n3 Pipeline and Hazardous Materials Safety Administration, Special Permit PHMSA-2006-26617\n(Washington, DC: US Department of Transportation, Pipeline and Hazardous Materials Administration, 2006)\nhttps://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/TC_Keystone_2007-04-30_508compliant.pdf\n2\n\n<<<PAGE 3>>>\n\nTransCanada Corporation Pipeline (Keystone Pipeline) Rupture\nshipped to the NTSB materials laboratory for examination. Figure 2 shows the ruptured pipe after\nexcavation and prior to shipment to the NTSB.\nFigure 2. Ruptured pipe.\nAt the NTSB materials laboratory, the ruptured pipe piece was cleaned and visually\nexamined. The metallurgists found midway along the length of the fracture face (a region of\n5.52 inches long), ratchet marks, crack arrest lines, and other features consistent with a\nmultiple-origin fatigue fracture that originated at an external groove in the pipe wall. (See figure 3.)\nThe fatigue origin area was located near the top of the pipe about 6.5 inches away from the\nlongitudinal seam. The pipe exterior exhibited areas of exposed metal and grooves formed by\nsliding contact that aligned nearly parallel to the pipe axis on the exterior surface coinciding and\nadjacent to the length of the fracture. Coating material was present and intermixed with the sliding\ncontact marks, and many edges of the remaining coating adjacent to individual contact marks were\ncurled and rounded consistent with sliding contact deformation. As shown on the right side of\nfigure 3, a larger cluster of grooves was present toward the upstream end of the fracture.\n3\n\n<<<PAGE 4>>>\n\nTransCanada Corporation Pipeline (Keystone Pipeline) Rupture\nFLOW Girth\nweld\nFatigue\nfracture\nregion\nGroove\nfeatures\nFigure 3. Overview of the pipe fracture with mating sides of the fracture placed adjacent to each\nother. The inset image shows a closer view of the fatigue facture initiation region and a colony of\nsliding-contact grooves.\nCompositional analysis of the grooved surfaces and of cross-sections through the grooves\nnear the fatigue crack origin area revealed that smeared metal in the trough of the sliding\ncontact-grooves contained higher concentrations of chromium than the pipe material (as\ndetermined by energy dispersive spectroscopy and backscattered electron microscopy). This was\nconsistent with the presence of a deposited layer.\nThe composition of the deposited metal in the grooves, and the morphology of the groove\ncolonies is consistent with damage that would result from the pipe being run over by a metal-\ntracked construction vehicle. The composition of the concrete weights was examined and ruled out\nas a source of the mechanical damage to the pipe. A full report of the metallurgical examination\ncan be found in accident docket PLD18LR001.\n4\n\n<<<PAGE 5>>>\n\nTransCanada Corporation Pipeline (Keystone Pipeline) Rupture\nProbable Cause\nThe NTSB determines that the probable cause of the failure of the Keystone Pipeline was\na fatigue crack, likely originating from mechanical damage to the pipe exterior by a metal-tracked\nvehicle during pipeline installation, that grew and extended in-service to a critical size, resulting\nin the rupture of the pipeline.\nFor more details about this accident, visit www.ntsb.gov/investigations/dms.html and search for\nNTSB accident identification PLD18LR001.\nAdopted: July 5, 2018\nThe NTSB has authority to investigate and establish the facts, circumstances, and cause or\nprobable cause of a pipeline accident in which there is a fatality or substantial property damage,\nor significant injury to the environment. (49 U.S. Code, Section 1131 - General authority)\nThe NTSB does not assign fault or blame for an accident or incident: rather, as specified by NTSB\nregulation, “accident/incident investigations are fact-finding proceedings with no formal issues\nand no adverse parties…and are not conducted for the purpose of determining the rights or\nliabilities of any person.” Title 49 Code of Federal Regulations, Section 831.4. Assignment of\nfault or legal liability is not relevant to the NTSB’s statutory mission to improve transportation\nsafety by investigating accidents and incidents and issuing safety recommendations. In addition,\nstatutory language prohibits the admission into evidence or use of any part of an NTSB report\nrelated to an accident in a civil action for damages resulting from a matter mentioned in the report.\n49 U.S. Code, Section 1154(b).\n5","truncated":false,"body_characters":12469}