{"operation":"document","citation":"DCA10MP007","title":"Enbridge Incorporated Hazardous Liquid Pipeline Rupture and Release","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"2020-11-30","effective_on":"2010-07-25","summary":"Accident. in Marshall, MI, USA. on 2010-07-25. Enbridge Energy. Rupture/release","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-dca10mp007.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-dca10mp007.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-dca10mp007","source_url":"https://www.ntsb.gov/investigations/Pages/DCA10MP007.aspx","body":"NTSB investigation DCA10MP007.\n\nEvent Type: Accident\n\nEvent Date: 2010-07-25\n\nEvent City: Marshall\n\nEvent State Or Region: MI\n\nEvent Country: USA\n\nPipeline Operator: Enbridge Energy\n\nAccident Type: Rupture/release\n\nCompletion Status: Completed\n\nReport Number: PAR1201\n\nProbable cause: The National Transportation Safety Board (NTSB) determines that the probable cause of the pipeline rupture was corrosion fatigue cracks that grew and coalesced from crack and corrosion defects under disbonded polyethylene tape coating, producing a substantial crude oil release that went undetected by the control center for over 17 hours. The rupture and prolonged release were made possible by pervasive organizational failures at Enbridge Incorporated (Enbridge) that included the following: Deficient integrity management procedures, which allowed well-documented crack defects in corroded areas to propagate until the pipeline failed. Inadequate training of control center personnel, which allowed the rupture to remain undetected for 17 hours and through two startups of the pipeline. Insufficient public awareness and education, which allowed the release to continue for nearly 14 hours after the first notification of an odor to local emergency response agencies. Contributing to the accident was the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) weak regulation for assessing and repairing crack indications, as well as PHMSA’s ineffective oversight of pipeline integrity management programs, control center procedures, and public awareness. Contributing to the severity of the environmental consequences were (1) Enbridge’s failure to identify and ensure the availability of well-trained emergency responders with sufficient response resources, (2) PHMSA’s lack of regulatory guidance for pipeline facility response planning, and (3) PHMSA’s limited oversight of pipeline emergency preparedness that led to the approval of a deficient facility response plan.\n\nTier1Name: Initiating product flow\n\nTier2Name: System warning/signal\n\nTier1Name: System operating, changing flow/pressure\n\nTier2Name: Emergency shutoff\n\nTier1Name: System operating\n\nTier2Name: Emergency shutoff\n\nTier1Name: Initiating product flow\n\nTier2Name: System warning/signal\n\nTier1Name: System shutdown\n\nTier2Name: System warning/signal\n\nTier1Name: Post-release\n\nTier2Name: Inspection event\n\nTier1Name: Post-release\n\nTier2Name: Emergency shutoff\n\nTier1Name: Post-release\n\nTier2Name: System disabled\n\nTier1Name: Post-release\n\nTier2Name: Emergency response\n\nTier1Name: System operating, changing flow/pressure\n\nTier2Name: System warning/signal\n\nTier1Name: System maintenance\n\nTier2Name: Product leak/release\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Management\n\nFinding Tier3Name: Policy/procedure\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Management - Policy/procedure - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Safety programs\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Training\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Training - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Management\n\nFinding Tier3Name: Culture\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Management - Culture - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Oversight\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Oversight - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Safety programs\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Oversight\n\nFinding Modifier Name: Federal agency\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Oversight - Federal agency\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Management\n\nFinding Tier3Name: Resources\n\nFinding Modifier Name: Emergency services\n\nFinding Report Text: Organizational - Management - Resources - Emergency services\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Development\n\nFinding Tier3Name: Design\n\nFinding Modifier Name: Other institution/organization\n\nFinding Report Text: Organizational - Development - Design - Other institution/organization\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Safety programs\n\nFinding Modifier Name: Federal agency\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - Federal agency\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Development\n\nFinding Tier3Name: Selection/testing\n\nFinding Modifier Name: Inspection organization\n\nFinding Report Text: Organizational - Development - Selection/testing - Inspection organization\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Management\n\nFinding Tier3Name: Policy/procedure\n\nFinding Modifier Name: Product source organization\n\nFinding Report Text: Organizational - Management - Policy/procedure - Product source organization\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Safety programs\n\nFinding Modifier Name: Emergency services\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - Emergency services\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Management\n\nFinding Tier3Name: Policy/procedure\n\nFinding Modifier Name: Federal agency\n\nFinding Report Text: Organizational - Management - Policy/procedure - Federal agency\n\nFinding Tier1Name: Personnel\n\nFinding Tier2Name: Experience/knowledge\n\nFinding Tier3Name: Training\n\nFinding Tier4Name: (general)\n\nFinding Modifier Name: Other company personnel\n\nFinding Report Text: Personnel - Experience/knowledge - Training - Other company personnel\n\nFinding Tier1Name: Personnel\n\nFinding Tier2Name: Experience/knowledge\n\nFinding Tier3Name: Training\n\nFinding Tier4Name: (general)\n\nFinding Modifier Name: SCADA operations personnel\n\nFinding Report Text: Personnel - Experience/knowledge - Training - SCADA operations personnel\n\nFinding Tier1Name: Personnel\n\nFinding Tier2Name: Task performance\n\nFinding Tier3Name: Planning/preparation\n\nFinding Modifier Name: Emergency services personnel\n\nFinding Report Text: Personnel - Task performance - Planning/preparation - Emergency services personnel\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipeline operation/capability\n\nFinding Tier3Name: Pipeline integrity/capacity\n\nFinding Modifier Name: Related operating info\n\nFinding Report Text: Pipeline - Pipeline operation/capability - Pipeline integrity/capacity - Related operating info\n\nFinding Tier1Name: Personnel\n\nFinding Tier2Name: Experience/knowledge\n\nFinding Tier3Name: Training\n\nFinding Tier4Name: (general)\n\nFinding Modifier Name: Emergency services personnel\n\nFinding Report Text: Personnel - Experience/knowledge - Training - Emergency services personnel\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipline systems/equipment\n\nFinding Tier3Name: Leak sensors\n\nFinding Modifier Name: Design\n\nFinding Report Text: Pipeline - Pipline systems/equipment - Leak sensors - Design\n\nFinding Tier1Name: Personnel\n\nFinding Tier2Name: Action/decision\n\nFinding Tier3Name: Information processing/decision making\n\nFinding Modifier Name: SCADA operations personnel\n\nFinding Report Text: Personnel - Action/decision - Information processing/decision making - SCADA operations personnel\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipeline handling/service\n\nFinding Tier3Name: Maintenance/inspection\n\nFinding Modifier Name: Fatigue/wear/corrosion\n\nFinding Report Text: Pipeline - Pipeline handling/service - Maintenance/inspection - Fatigue/wear/corrosion\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 July 25, 2010, a segment of a 30-inch-diameter pipeline (Line 6B), owned and operated by Enbridge Incorporated (Enbridge) ruptured in a wetland in Marshall, Michigan. The rupture occurred during the last stages of a planned shutdown and was not discovered or addressed for over 17 hours. During the time lapse, Enbridge twice pumped additional oil (81 percent of the total release) into Line 6B during two startups; the total release was estimated to be 843,444 gallons of crude oil. The oil saturated the surrounding wetlands and flowed into the Talmadge Creek and the Kalamazoo River. Local residents self-evacuated from their houses, and the environment was negatively affected. Cleanup efforts continue as of the adoption date of this report, with continuing costs exceeding $767 million. About 320 people reported symptoms consistent with crude oil exposure. No fatalities were reported.\n\nWhat We Found\nThe probable cause of the pipeline rupture was corrosion fatigue cracks that grew and coalesced from crack and corrosion defects under disbonded polyethylene tape coating, producing a substantial crude oil release that went undetected by the control center for over 17 hours. The rupture and prolonged release were made possible by pervasive organizational failures at Enbridge Incorporated (Enbridge) that included the following:\nDeficient integrity management procedures, which allowed well-documented crack defects in corroded areas to propagate until the pipeline failed.\nInadequate training of control center personnel, which allowed the rupture to remain undetected for 17 hours and through two startups of the pipeline.\nInsufficient public awareness and education, which allowed the release to continue for nearly 14 hours after the first notification of an odor to local emergency response agencies.\nContributing to the accident was the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) weak regulation for assessing and repairing crack indications, as well as PHMSA’s ineffective oversight of pipeline integrity management programs, control center procedures, and public awareness.\nContributing to the severity of the environmental consequences were (1) Enbridge’s failure to identify and ensure the availability of well-trained emergency responders with sufficient response resources, (2) PHMSA’s lack of regulatory guidance for pipeline facility response planning, and (3) PHMSA’s limited oversight of pipeline emergency preparedness that led to the approval of a deficient facility response plan.\n\nWhat We Recommended\nAs a result of its investigation of this accident, we made recommendations to the U.S. Secretary of Transportation, the Pipeline and Hazardous Materials Safety Administration (PHMSA), Enbridge, the American Petroleum Institute, the Pipeline Research Council International, the International Association of Fire Chiefs, and the National Emergency Number Association. The NTSB also reiterates a previous recommendation to PHMSA.\n\nPAR-12-01\n<<<PAGE 1>>>\n\nEnbridge Incorporated\nHazardous Liquid Pipeline Rupture and Release\nMarshall, Michigan\nJuly 25, 2010\nAccident Report\nNTSB/PAR-12/01\nPB2012-916501\nNational\nTransportation\nSafety Board\n\n<<<PAGE 2>>>\n\nNTSB/PAR-12/01\nPB2012-916501\nNotation 8423\nAdopted July 10, 2012\nPipeline Accident Report\nEnbridge Incorporated\nHazardous Liquid Pipeline Rupture and Release\nMarshall, Michigan\nJuly 25, 2010\nNational\nTransportation\nSafety Board\n490 L’Enfant Plaza, S.W.\nWashington, D.C. 20594\n\n<<<PAGE 3>>>\n\nNational Transportation Safety Board. 2012. Enbridge Incorporated Hazardous Liquid Pipeline\nRupture and Release, Marshall, Michigan, July 25, 2010. Pipeline Accident Report\nNTSB/PAR-12/01. Washington, D.C.\nAbstract: On Sunday, July 25, 2010, at 5:58 p.m., eastern daylight time, a segment of a 30-inch-diameter\npipeline (Line 6B), owned and operated by Enbridge Incorporated (Enbridge) ruptured in a wetland in\nMarshall, Michigan. The rupture occurred during the last stages of a planned shutdown and was not\ndiscovered or addressed for over 17 hours. During the time lapse, Enbridge twice pumped additional oil\n(81 percent of the total release) into Line 6B during two startups; the total release was estimated to be\n843,444 gallons of crude oil. The oil saturated the surrounding wetlands and flowed into the\nTalmadge Creek and the Kalamazoo River. Local residents self-evacuated from their houses, and the\nenvironment was negatively affected. Cleanup efforts continue as of the adoption date of this report, with\ncontinuing costs exceeding $767 million. About 320 people reported symptoms consistent with crude oil\nexposure. No fatalities were reported.\nAs a result of its investigation of this accident, the National Transportation Safety Board (NTSB) makes\nrecommendations to the U.S. Secretary of Transportation, the Pipeline and Hazardous Materials Safety\nAdministration (PHMSA), Enbridge, the American Petroleum Institute, the Pipeline Research Council\nInternational, the International Association of Fire Chiefs, and the National Emergency Number\nAssociation. The NTSB also reiterates a previous recommendation to PHMSA.\nThe National Transportation Safety Board (NTSB) is an independent Federal agency dedicated to promoting\naviation, railroad, highway, marine, pipeline, and hazardous materials safety. Established in 1967, the agency is\nmandated by Congress through the Independent Safety Board Act of 1974 to investigate transportation accidents,\ndetermine the probable causes of the accidents, issue safety recommendations, study transportation safety issues, and\nevaluate the safety effectiveness of government agencies involved in transportation. The NTSB makes public its\nactions and decisions through accident reports, safety studies, special investigation reports, safety recommendations,\nand statistical reviews.\nRecent publications are available in their entirety on the Internet at <http://www.ntsb.gov>. Other information about\navailable publications also may be obtained from the website or by contacting:\nNational Transportation Safety Board\nRecords Management Division, CIO-40\n490 L’Enfant Plaza, SW\nWashington, D.C. 20594\n(800) 877-6799 or (202) 314-6551\nNTSB publications may be purchased, by individual copy or by subscription, from the National Technical\nInformation Service. To purchase this publication, order report number PB2012-916501 from:\nNational Technical Information Service\n5301 Shawnee Road\nAlexandria, Virginia 22312\n(800) 553-6847 or (703) 605-6000\nThe Independent Safety Board Act, as codified at 49 U.S.C. Section 1154(b), precludes the admission into evidence\nor use of NTSB reports related to an incident or accident in a civil action for damages resulting from a matter\nmentioned in the report.\n\n<<<PAGE 4>>>\n\nNTSB Pipeline Accident Report\nContents\nFigures .......................................................................................................................................... vii\nTables ............................................................................................................................................ ix\nAcronyms and Abbreviations .......................................................................................................x\nExecutive Summary .................................................................................................................... xii\n1 Factual Information .................................................................................................................1\n1.1 Introduction ..............................................................................................................................1\n1.2 Accident Narrative ...................................................................................................................8\n1.2.1 Preaccident Events .........................................................................................................8\n1.2.2 The Rupture—Shift A ....................................................................................................8\n1.2.3 First Line 6B Startup—Shift B ....................................................................................10\n1.2.4 Second Line 6B Startup—Shift B ................................................................................13\n1.2.5 Discovery—Shift C ......................................................................................................14\n1.2.6 Enbridge Initial Response ............................................................................................15\n1.3 Injuries and Evacuations ........................................................................................................18\n1.3.1 Injuries .........................................................................................................................18\n1.3.2 Evacuations ..................................................................................................................18\n1.4 Damages .................................................................................................................................18\n1.4.1 Pipeline ........................................................................................................................18\n1.4.2 Environment .................................................................................................................19\n1.5 Environmental Conditions ......................................................................................................19\n1.5.1 Meteorological .............................................................................................................19\n1.5.2 Kalamazoo River Conditions .......................................................................................19\n1.6 Pipeline Information ...............................................................................................................19\n1.6.1 Pipeline History ...........................................................................................................19\n1.6.2 Pipeline Operating Pressure .........................................................................................20\n1.6.3 Site Description ............................................................................................................20\n1.6.4 Other Enbridge Pipeline Incidents ...............................................................................20\n1.6.4.1 Cohasset, Minnesota....................................................................................21\n1.6.4.2 Glenavon, Saskatchewan .............................................................................22\n1.7 Examination of the Accident Pipe ..........................................................................................23\n1.7.1 Coating .........................................................................................................................24\n1.7.2 Corrosion......................................................................................................................24\n1.7.3 Microbial Corrosion .....................................................................................................24\n1.7.4 The Fracture .................................................................................................................25\n1.7.5 Crack and Corrosion Depth Profile..............................................................................28\n1.7.6 Mechanical Testing and Chemical Analysis ................................................................29\n1.8 PHMSA Integrity Management Regulation ...........................................................................29\n1.8.1 Pipeline Integrity Management in High Consequence Areas ......................................29\n1.8.2 Elements of Integrity Management and Integration of Threats ...................................30\niii\n\n<<<PAGE 5>>>\n\nNTSB Pipeline Accident Report\n1.8.3 Discovery of Condition ................................................................................................30\n1.8.4 Immediate and 180-Day Conditions ............................................................................31\n1.9 Enbridge Integrity Management Program ..............................................................................31\n1.9.1 Corrosion Management ................................................................................................32\n1.9.2 Crack Management ......................................................................................................32\n1.9.3 In-line Inspection Intervals ..........................................................................................33\n1.9.4 Stress Corrosion Cracking ...........................................................................................34\n1.9.5 Coating and Cathodic Protection .................................................................................34\n1.9.6 In-line Inspection Tools ...............................................................................................35\n1.9.6.1 USCD Tool ..................................................................................................35\n1.9.7 Enbridge Postaccident Threat Assessment Review .....................................................36\n1.9.8 Prior In-Line Inspections of Line 6B ...........................................................................37\n1.9.8.1 2004 Ultrasonic Wall Measurement In-Line Inspection .............................37\n1.9.8.2 2005 In-Line Inspection—PII USCD Crack Tool Results ..........................39\n1.9.8.3 2007 In-Line Inspection—PII High-Resolution MFL Tool Results ...........41\n1.9.8.4 2009 In-Line Inspection—PII USWM Tool Results ...................................41\n1.10 Pipeline Public Awareness Programs .....................................................................................42\n1.10.1 Regulatory Requirements.............................................................................................42\n1.10.2 API Recommended Practice 1162 ...............................................................................42\n1.10.3 Enbridge’s PAP ............................................................................................................42\n1.11 Enbridge Operations ...............................................................................................................44\n1.11.1 Edmonton Control Center ............................................................................................44\n1.11.2 Control Center Personnel Experience ..........................................................................45\n1.11.3 Toxicology ...................................................................................................................47\n1.11.4 Training and Qualifications .........................................................................................47\n1.11.4.1 Control Center Operations ..........................................................................47\n1.11.4.2 MBS Analyst ...............................................................................................48\n1.11.5 MBS Leak Detection....................................................................................................49\n1.11.5.1 Federal Regulations .....................................................................................49\n1.11.5.2 API 1130 Computational Pipeline Monitoring for Liquids ........................49\n1.11.5.3 Enbridge’s MBS ..........................................................................................50\n1.11.5.4 Column Separation ......................................................................................51\n1.11.6 Procedures ....................................................................................................................52\n1.11.6.1 10-Minute Restriction .................................................................................52\n1.11.6.2 Suspected Column Separation .....................................................................52\n1.11.6.3 MBS Alarm .................................................................................................53\n1.11.6.4 SCADA Leak Triggers ................................................................................53\n1.11.6.5 Suspected Leak—Volume Difference .........................................................54\n1.11.6.6 Leak and Obstruction Trigger—On Startup from SCADA Data ................54\n1.11.7 Fatigue Management ....................................................................................................54\n1.11.8 Enbridge Health and Safety Management System.......................................................55\n1.12 Environmental Response ........................................................................................................55\n1.12.1 Volume Released .........................................................................................................55\n1.12.2 Hazardous Materials Information ................................................................................56\n1.12.3 Overview of the Oil Spill Response.............................................................................56\n1.12.3.1 Notifications ................................................................................................58\niv\n\n<<<PAGE 6>>>\n\nNTSB Pipeline Accident Report\n1.12.4 Enbridge Facility Response Plan .................................................................................58\n1.12.5 EPA Oversight of Spill Response Efforts ....................................................................61\n1.12.6 Environmental Monitoring...........................................................................................62\n1.12.6.1 Air Quality...................................................................................................62\n1.12.6.2 Potable Water ..............................................................................................62\n1.12.6.3 Surface Water and Sediment .......................................................................62\n1.12.7 Natural Resources and Wildlife ...................................................................................63\n1.13 Previous NTSB Investigations and Studies ............................................................................63\n1.13.1 NTSB SCADA 2005 Study .........................................................................................63\n1.13.2 NTSB 2010 Pipeline Investigation of Pacific Gas and Electric Company ..................64\n1.13.3 Carmichael, Mississippi ...............................................................................................65\n1.14 Postaccident Actions ..............................................................................................................65\n1.14.1 PHMSA Corrective Action Order ................................................................................65\n1.14.2 PHMSA’s Notice of Probable Violation......................................................................66\n1.14.3 Enbridge Actions .........................................................................................................66\n1.14.3.1 Line 6B Replacement Projects ....................................................................66\n1.14.3.2 Enbridge Operator Training ........................................................................67\n1.14.3.3 Integrity Management .................................................................................67\n1.14.3.4 Enbridge Control Center .............................................................................67\n1.15 Federal Oversight ...................................................................................................................68\n1.15.1 Canadian and U.S. Regulation .....................................................................................68\n1.15.2 Enbridge 2010 Long-Term Pressure Reduction Notification ......................................69\n1.15.3 PHMSA Inspections.....................................................................................................69\n1.15.4 Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011 ........................71\n1.15.5 National Energy Board ................................................................................................71\n1.15.6 PHMSA Inspection of Enbridge’s PAP .......................................................................72\n1.15.7 PHMSA Facility Response Plan Review and Approval ..............................................73\n1.15.8 PHMSA Facility Response Plan Advisory Bulletin ....................................................75\n1.15.9 Response Preparedness ................................................................................................75\n1.15.10 PHMSA Control Center Management ...................................................................76\n1.16 Other Information ...................................................................................................................78\n1.16.1 Oil Spill Response Methods.........................................................................................78\n1.16.2 API Standard 1160—Managing System Integrity for Hazardous Liquid Pipelines ....80\n2 Analysis ...................................................................................................................................81\n2.1 Introduction ............................................................................................................................81\n2.2 Pipeline Failure .......................................................................................................................82\n2.2.1 The Rupture .................................................................................................................82\n2.2.2 Fracture Mechanism.....................................................................................................82\n2.3 Federal Regulations Governing Hazardous Liquid Pipelines ................................................84\n2.4 Deficiencies in the Integrity Management Program ...............................................................87\n2.4.1 Engineering Assessment of Cracks and Margin of Safety ...........................................88\n2.4.2 In-line Inspection Tool Tolerances ..............................................................................88\n2.4.3 Improper Wall Thickness .............................................................................................89\n2.4.4 Corrosion and Cracking Interactions ...........................................................................89\n2.4.5 Crack Growth Rate Not Considered ............................................................................90\n2.4.6 Need for Continuous Reassessment .............................................................................90\nv\n\n<<<PAGE 7>>>\n\nNTSB Pipeline Accident Report\n2.4.7 Effect of Integrity Management Deficiencies ..............................................................91\n2.5 Mischaracterization of the Crack Feature ..............................................................................93\n2.6 Control Center ........................................................................................................................93\n2.6.1 Team Performance .......................................................................................................94\n2.6.2 Training ........................................................................................................................97\n2.6.3 Procedures ....................................................................................................................98\n2.6.4 Tolerance for Procedural Deviance ...........................................................................101\n2.6.5 Alcohol and Drug Testing ..........................................................................................101\n2.6.6 Work/Sleep/Wake History .........................................................................................102\n2.7 Pipeline Public Awareness ...................................................................................................103\n2.8 Environmental Response ......................................................................................................105\n2.8.1 Effectiveness of the Emergency Response to this Accident ......................................105\n2.8.2 Facility Response Planning ........................................................................................108\n2.8.2.1 Regulatory Requirements for Facility Response Planning .......................109\n2.8.2.2 Adequacy of Enbridge Facility Response Plan .........................................111\n2.8.2.3 PHMSA Oversight of Facility Response Plans .........................................112\n2.9 Summary of Enbridge Organizational Deficiencies .............................................................114\n3 Conclusions ...........................................................................................................................118\n3.1 Findings ................................................................................................................................118\n3.2 Probable Cause .....................................................................................................................121\n4 Recommendations ................................................................................................................122\n4.1 New Recommendations ........................................................................................................122\n4.2 Reiterated Recommendation ................................................................................................124\n5 Appendixes............................................................................................................................126\n5.1 Appendix A: Investigation ...................................................................................................126\n5.2 Appendix B: Enbridge’s MBS and Control Center Operations Procedures ........................127\n5.3 Appendix C: Supervisory Control and Data Acquisition Plots ............................................146\nvi\n\n<<<PAGE 8>>>\n\nNTSB Pipeline Accident Report\nFigures\nFigure 1. Enbridge’s Liquids System and the 1,900-mile Lakehead System (the\nU.S. portion). Inset shows Line 6B, the 293-mile extension from Griffith to Sarnia installed\nin 1969. ........................................................................................................................................... 2\nrupture. The fracture face measured about 6 feet 8.25 inches long and was 5.32 inches wide\nFigure 2 . The ruptured segment of Line 6B in the trench following the July 25, 2010,\nat the widest opening. The fracture ran just below the seam weld that was oriented just\nbelow the 3 o’clock position. A red circle shows a location where the coating was wrinkled\nand had separated from the pipe surface. ........................................................................................ 3\nFigure 3. Aerial view of the accident location showing the rupture site to the left and the\nTalmadge Creek flowing west toward the Kalamazoo River. ........................................................ 4\nFigure 4. Cleanup efforts in an oil-soaked wetland near the rupture site. Saturated soil\ncomplicated the cleanup and excavation efforts. An excavator with a vacuum attachment is\nshown situated on wooden matting near the rupture site. ............................................................... 5\nFigure 5. Key events timeline of the Line 6B rupture in Marshall, Michigan, showing the\nevents from the time of rupture on July 25, 2010, to the time of discovery on July 26, 2010. ...... 6\nFigure 6. Key Enbridge staff involved in the 17-hour accident sequence. MBS refers to\nMaterial Balance System. ............................................................................................................... 7\nFigure 7. Simplified schematic of Line 6B, showing pump stations and delivery locations. ........ 9\nFigure 8. Emergency response and 911 calls from nearby residents. First and last calls are\nnoted. ............................................................................................................................................. 11\nFigure 9. Area between rupture site and the Kalamazoo River where first responders\nconcentrated efforts to contain the released oil. ............................................................................ 15\nFigure 10. Underflow dam on Talmadge Creek on July 30, 2010. .............................................. 17\nFigure 11. Line 6B ruptured segment showing upstream and downstream sections used for\nMaterials Laboratory examination. Detail B shows tented coating over the longitudinal\nseam weld...................................................................................................................................... 23\nFigure 12. The outside surface of the pipe looking at the fracture area cut for lab\nexamination. .................................................................................................................................. 25\nFigure 13. Curving arrest lines of preexisting cracks along the upper fracture face shown\nafter cleaning to remove oxides. White arrows indicate multiple origin areas of preexisting\ncracks. ........................................................................................................................................... 26\nvii\n\n<<<PAGE 9>>>\n\nNTSB Pipeline Accident Report\nFigure 14. Close view of fracture surface area in the area of deepest crack penetration. The\nsolid blue line indicates the extent of the preexisting crack penetration. ..................................... 27\nFigure 15. Transverse section through the top of the fracture showing multiple parallel\ncracks emanating from corrosion pits on the outside surface. ...................................................... 28\nFigure 16. Lab measurements of crack and corrosion depths along the fracture face\nmeasured from images similar to figure 14 near area of deepest penetration (about\n344 inches from upstream girth weld). ......................................................................................... 29\nFigure 17. 2004 corrosion inspection of Line 6B and 16 regions of corrosion identified by\nthe tool on the ruptured pipe segment. The detail view shows the areas of corrosion\noverlapped with the rupture location. ........................................................................................... 38\nFigure 18. 2005 in-line inspection regions where crack-like characterizations were\nreported by PII on the ruptured segment of Line 6B. ................................................................... 40\nFigure 19. Map showing rupture location and affected waterways from Talmadge Creek to\nMorrow Lake. ............................................................................................................................... 57\nFigure 2 0. Enbridge PLM emergency response trailer containing the company’s Tier 1 oil\ncontainment equipment, October 17, 2010. .................................................................................. 60\nFigure 2 1. (Left) Enbridge employees install sorbent boom in f","truncated":true,"body_characters":407832}