{"operation":"document","citation":"PLD24FR001","title":"Third Coast Infrastructure LLC Crude Oil Release","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"2025-07-16","effective_on":"2023-11-15","summary":"Accident. in Gulf of America Main Pass 69, LA, USA. on 2023-11-15. Third Coast Infrastructure, LLC. Leak","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-pld24fr001.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-pld24fr001.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-pld24fr001","source_url":"https://www.ntsb.gov/investigations/Pages/PLD24FR001.aspx","body":"NTSB investigation PLD24FR001.\n\nEvent Type: Accident\n\nEvent Date: 2023-11-15\n\nEvent City: Gulf of America Main Pass 69\n\nEvent State Or Region: LA\n\nEvent Country: USA\n\nPipeline Operator: Third Coast Infrastructure, LLC\n\nPipeline Type: Hazardous Liquid - Regulated\n\nAccident Type: Leak\n\nCompletion Status: Completed\n\nReport Number: PIR2502\n\nReport Date: 2025-06-13\n\nProbable cause: The National Transportation Safety Board determines the probable cause of the 18-inch diameter Main Pass Oil Gathering pipeline crude oil release was the loss of seal in a collet grip pipeline fitting from pipeline movement caused by geohazards that had not been addressed previously by Third Coast’s insufficient integrity management program. Contributing to the volume of crude oil released was an inappropriate control room response that did not shut down the pipeline system because of the controller’s uncertainty about the accuracy of data from a supervisory control and data acquisition system that indicated but did not alert the operator of a leak for more than 11 hours.\n\nTier1Name: System operating\n\nTier2Name: Product leak/release\n\nTier1Name: System operating\n\nTier2Name: Pipe structural malfunction/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\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipline systems/equipment\n\nFinding Tier3Name: Fittings\n\nFinding Modifier Name: Capability exceeded\n\nFinding Report Text: Pipeline - Pipline systems/equipment - Fittings - Capability exceeded\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 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: Personnel\n\nFinding Tier2Name: Action/decision\n\nFinding Tier3Name: Action\n\nFinding Modifier Name: SCADA operations personnel\n\nFinding Report Text: Personnel - Action/decision - Action - SCADA operations personnel\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 15, 2023, about 7:00 p.m. local time, an 18-inch underwater crude oil pipeline released about 1.1 million gallons of crude oil into an unusually sensitive area in Main Pass 69 in the Gulf of America, southeast of Venice, Louisiana, in Louisiana state waters. The pipeline is part of the Main Pass Oil Gathering (MPOG) pipeline system, owned by Houston, Texas–based midstream company Third Coast Infrastructure LLC and operated by affiliate Panther Operating Company.2 The weather at the time of the accident was 73°F with light rain and east-northeast winds of 41 mph with 48-mph gusts. No injuries were reported, and the crude oil did not ignite.\n\nWhat We Found\nWe determined the probable cause of the 18-inch diameter Main Pass Oil Gathering pipeline crude oil release was the loss of seal in a collet grip pipeline fitting from pipeline movement caused by geohazards that had not been addressed previously by Third Coast’s insufficient integrity management program.\nContributing to the volume of crude oil released was an inappropriate control room response that did not shut down the pipeline system because of the controller’s uncertainty about the accuracy of data from a supervisory control and data acquisition system that indicated but did not alert the operator of a leak for more than 11 hours.\n\nLessons Learned\nPipeline operators must manage and address all threats to pipeline integrity, including those from weather events and geohazards. After the accident, Third Coast developed a program to monitor the MPOG pipeline system and collet grip fittings for possible pipe movement and to test and confirm the function of the fitting seals. PHMSA is overseeing modifications to Third Coast’s risk management program to include evaluations when mudflows or other geohazards occur.\n\nIn this accident, uncertainty about the accuracy of the supervisory control and data acquisition (SCADA) system data led to a delayed shutdown of the pipeline. The NTSB has investigated other accidents in which controllers, faced with control system information indicating an anomaly, have failed to shut down pipelines. In Marshall, Michigan, in 2010, controllers’ flawed interpretations of system data and alarms contributed to the delayed shutdown of a pipeline, which released 843,000 gallons of crude oil into wetlands. More recently, in 2021, pipeline controllers in San Pedro Bay, near Huntington Beach, California, did not shut down a leaking underwater crude oil pipeline for 14 hours after incorrectly determining that leak alarms were false.\n\nLeak detection tools help reduce uncertainty for controllers interpreting abnormal control system data. After the accident, Third Coast reported that it is implementing a leak detection software system specifically for MPOG and has added a leak detection alarm to its SCADA system, with a tolerance level based on historical flow patterns. The company also added information on leak detection to its control center operational procedures and related training.\n\nPIR-25-02\n<<<PAGE 1>>>\n\nPipeline Investigation Report\nPIR-25-02\nIssued: June 13, 2025 Pipeline Investigation Report: PIR-25-02\nThird Coast Infrastructure LLC\nCrude Oil Release\nLocation Main Pass 69, Louisiana state waters, Gulf of America\nDate November 15, 2023\nSystem type Hazardous liquid\nAccident type Leak\nPipeline operator Panther Operating Company, Third Coast Infrastructure LLC\nPipeline system Main Pass Oil Gathering System\nHazardous materials Crude oil\nFatalities/injuries None\nDamages $30 million\nSummary\nOn November 15, 2023, about 7:00 p.m. local time, an 18-inch underwater crude\noil pipeline released about 1.1 million gallons of crude oil into an unusually sensitive area\nin Main Pass 69 in the Gulf of America, southeast of Venice, Louisiana, in Louisiana state\nwaters.\n1 (See figure 1.) The pipeline is part of the Main Pass Oil Gathering (MPOG)\npipeline system, owned by Houston, Texas–based midstream company Third Coast\nInfrastructure LLC and operated by affiliate Panther Operating Company.\n2 The weather\nat the time of the accident was 73°F with light rain and east-northeast winds of 41 mph\nwith 48-mph gusts. No injuries were reported, and the crude oil did not ignite.\nOn November 16, the US Coast Guard and Third Coast began the initial response\nto the accident. The following day, the Coast Guard convened a unified command,\ncomprised of federal and state agencies including the Pipeline and Hazardous Materials\nSafety Administration, the Bureau of Safety and Environmental Enforcement, the\n1 (a) All times in this report are local. (b) Visit ntsb.gov to find additional information in the public docket\nfor this NTSB accident investigation (case number PLD24FR001), including detailed factual reports about\nthe circumstances of the accident. (c) Title 49 Code of Federal Regulations (CFR) Part 195.6 defines an\nunusually sensitive area as a drinking water or ecological resource area that is unusually sensitive to\nenvironmental damage from a hazardous liquid pipeline release.\n2 The MPOG crude oil pipeline system starts in Main Pass 225 and delivers crude oil to the MP69\nstation, a facility in Main Pass 69 owned by Crescent Midstream. Crude oil is introduced into the system at\nsix pipeline connection points in the Gulf.\n1\n\n<<<PAGE 2>>>\n\nPipeline Investigation Report\nPIR-25-02\nLouisiana Oil Spill Coordinator’s Office, and the Louisiana Department of Wildlife and\nFisheries, which coordinated oil spill response activities until April 2024.\n3\nFigure 1. Oil slick in Main Pass 69, observed November 18, 2023. (Source: Bureau of Safety and\nEnvironmental Enforcement.)\nAt the time of the accident, the MPOG system provided midstream services to\ncrude oil producers in the Main Pass area and included 4 miles of 20-inch- and 61.8\nmiles of 18-inch-diameter hazardous liquid pipeline, with a maximum operating pressure\nof 1,950 pounds per square inch, gauge (psig). The control room for the MPOG system\n3 The unified command observed about 19 brown pelicans with oil residue on their feathers on\nNovember 19, 2023. All were capable of flight.\n2\n\n<<<PAGE 3>>>\n\nPipeline Investigation Report\nPIR-25-02\nwas located in Houston and staffed by pipeline controllers working 24 hours a day, 365\ndays a year, with one controller per 12-hour shift dedicated to MPOG and to nearby\npipeline systems.\n4\nThe controller on duty at the time of the accident began his shift at 6:00 p.m. on\nNovember 15. He reported to the National Transportation Safety Board (NTSB) that he\nfirst noticed the supervisory control and data acquisition (SCADA) system indicate\npressure changes in the MPOG system around 6:45 p.m. but added that these are\ncommon on an active pipeline.\n5 The controller recalled that he began investigating this\nevent because the volume of oil entering the pipeline was larger than the volume exiting\nthe pipeline at its delivery point. The controller conducted various troubleshooting\nactivities throughout the evening of November 15 in response to the observed volume\nimbalance and changes in pressure and flow rate data.\n6\nSCADA system records reviewed by the NTSB indicated changes in flow rate and\npressure for the MP69 station on the evening of November 15 with no change in the\noperating conditions of any of the MPOG pipeline system assets. Flow rate fluctuations\nwere recorded starting about 6:12 p.m., with a significant decrease in flow rate\nbeginning just before 7:00 p.m.\nAbout 10:15 p.m. on November 15, the controller reported the abnormal data to\nhis supervisor, who recommended not shutting down the pipeline. About 12:29 a.m.,\nthe flow rate at the MP69 station went to zero.7 SCADA system records also indicated a\ndecrease in the volume of oil leaving the system through the night, with about 1,100\nbarrels unaccounted for about 8:30 p.m. and 11,000 barrels at 1:30 a.m. on\nNovember 16.\nHe spoke with colleagues again after the data showed a zero flow rate at the\nMP69 station about 12:29 a.m. The controller told the NTSB that the valves at the MP69\nstation were programmed to close when the flow rate went to zero, but for unknown\nreasons, they did not close in this instance. The controller concluded, based on the\n4 A control room is a central location for monitoring and controlling pipeline operations.\n5 SCADA is a computer-based system used in a pipeline control room that collects and displays\ninformation about pipeline facilities.\n6 The controller told the NTSB that about 9:00 p.m. he called personnel at two other control rooms,\nincluding at the MP69 station, to verify whether they observed similar flow data decreases. In both cases,\nthe flow rates matched those shown by the SCADA system at his location. About 1:30 a.m., he requested a\nplatform operator at the MP69 station walk through to assess the equipment, but the team there reported\nthey found no equipment problems.\n7 Third Coast procedures did not require controllers to take an action when MP69 had zero flow.\n3\n\n<<<PAGE 4>>>\n\nPipeline Investigation Report\nPIR-25-02\nconversations with his colleagues and on the performance of the valves, that the data\nwere the result of equipment issues and did not shut down the pipeline. The controller\nended his shift about 6:00 a.m. on November 16.\nShortly after the shift change, day shift personnel reviewed pipeline pressure and\nflow trend data and noted the zero flow reading at the MP69 station.\n8 They began\nshutdown procedures about 6:30 a.m., and the pipeline system was isolated by\n9:00 a.m.9 Third Coast reported a leak to the US Environmental Protection Agency\nNational Response Center about 9:51 a.m.\nAfter the accident, Third Coast contracted divers and underwater\nremote-operated vehicles to survey the pipeline for the failure location. On December\n21, the divers found oil residue in the area of a collet grip fitting, approximately 40 feet\nbelow the surface of the water; this location was later confirmed as the leak location.\n10\n(See figure 2.)\n8 Shift leads joined controllers during daytime shifts Monday through Friday.\n9 By the time the pipeline was shut down, the volume imbalance recorded by the SCADA system was\nnearly 27,000 barrels.\n10 A collet grip fitting joins two segments of pipe by surrounding and gripping the outer pipe\ncircumference.\n4\n\n<<<PAGE 5>>>\n\nPipeline Investigation Report\nPIR-25-02\nFigure 2. Main Pass Oil Gathering pipeline and approximate leak location.\nThe NTSB recovered the fitting and piping for evaluation. The evaluation\ndetermined the fitting, as recovered, was capable of functioning as designed.\n(See figure 3.) The NTSB Materials Laboratory then evaluated the pipe that had been\ninstalled in the fitting, and the evaluation revealed that at the time of recovery, it had\nbeen pulled about 34 inches out of the fitting and was no longer in contact with the\nsealing surfaces in the fitting.\n5\n\n<<<PAGE 6>>>\n\nPipeline Investigation Report\nPIR-25-02\nFigure 3. Collet grip fitting recovered from the seafloor. (Photo: MPOG)\nThe NTSB reviewed records of MPOG system integrity assessments for the\ndecade preceding the accident. In 2012, a high-resolution magnetic flux leakage inline\ninspection (ILI) tool run found no pipeline anomalies that required action, and a\nhigh-resolution geometry and dent assessment ILI run in 2019 reported some corrosion\nmetal loss anomalies but no deformation anomalies. An acoustic resonance technology\nILI tool was run in October 2023, several weeks before the failure. After the accident, at\nthe request of the NTSB, the ILI vendor completed an enhanced evaluation of the data\nfrom this inspection. At the time of the October 2023 inspection, the pipe was found to\nhave moved within the fitting about 7.6 inches upstream from its original installation\nlocation but was still in contact with the fitting’s seals.\n6\n\n<<<PAGE 7>>>\n\nPipeline Investigation Report\nPIR-25-02\nAnalysis\nThe crude oil leak in this accident resulted from weather-related geohazards,\nwhich likely imposed forces that moved the pipe within its fitting over time.11 The leak\ncontinued from about 6:30 p.m. on November 15 until about 07:30 a.m. on November\n16, releasing about 1.1 million gallons of crude oil into an unusually sensitive area into\nLouisiana state waters in the Gulf of America.\nWhen the pipeline controller on duty on the night of the accident observed\nSCADA system data that indicated a possible leak, he consulted with colleagues and\ntried to evaluate the problem from the control room. Trending SCADA system data\noffered justification for the pipeline controller to shut down the pipeline system.\nHowever, although no equipment issues were observed, the controller told the NTSB\nthat his consultations with colleagues and the failure of the valves at MP69 to perform as\nprogrammed led him to doubt the accuracy of the SCADA data and deterred him from\nshutting down the pipeline. It was shut down the next morning by personnel on the\nfollowing shift. Had the controller shut down the pipeline when he first identified a flow\nmismatch, or when he first reported the issue to his management, far less crude oil\nwould have been released.\nAfter the accident, divers identified a likely failure location. Evaluations of the pipe\nand fitting at the location indicated that the pipe had moved within the fitting, leading to\na loss of the seal between the fitting and the pipe. The failure was consistent with land\nmovement caused by resident geohazards and weather events. Over time, the land\nmovement imposed forces on the underwater pipeline that stressed the underwater\npipeline, increasing pipeline integrity threats and affecting safe operation.\nIn the years leading up to the accident, Third Coast missed several opportunities\nto evaluate how geohazards may threaten the integrity of their pipeline. Information\nwidely available within the industry suggested that land movement related to hurricane\nactivity was a threat to pipelines in the Gulf of America, including the MPOG 18-inch\npipeline. Alignment maps from 2005, created after the pipeline was damaged by\nHurricane Ivan the year before, showed significant areas of exposed pipeline and\nmudflows over or near it, along with a mudflow in the same area as the November 2023\nfailure. Although the pipeline owner at the time repaired this damage, the National\nOceanic and Atmospheric Administration’s National Hurricane Center recorded\n12 additional hurricanes and 6 tropical storms in Main Pass 69 since Hurricane Ivan.\n11 Marine geohazards include submarine landslides or mudflows induced by natural processes that can\nharm, endanger, or affect seafloor facilities. A mudflow is the movement of underwater sediment caused by\ngravity or other forces.\n7\n\n<<<PAGE 8>>>\n\nPipeline Investigation Report\nPIR-25-02\nFurther, a 2022 hydrographic survey showed more than a dozen exposed sections of the\nMPOG 18-inch pipeline, as well as 24 locations where the pipeline may have been\nunsupported by the sea floor.12 Exposures and suspensions such as these can indicate\ndetrimental forces acting on a pipeline.\nAn effective pipeline integrity program would have incorporated information on\npotential weather-related geohazards to identify pipeline areas for further assessment.\nAlthough Third Coast corrected the unsupported and exposed sections of the MPOG\n18-inch pipeline in 2023, it did not evaluate the potential for the pipeline to move and for\nthe fitting to fail before the accident.\nProbable Cause\nThe National Transportation Safety Board determines the probable cause of the\n18-inch diameter Main Pass Oil Gathering pipeline crude oil release was the loss of seal\nin a collet grip pipeline fitting from pipeline movement caused by geohazards that had\nnot been addressed previously by Third Coast’s insufficient integrity management\nprogram. Contributing to the volume of crude oil released was an inappropriate control\nroom response that did not shut down the pipeline system because of the controller’s\nuncertainty about the accuracy of data from a supervisory control and data acquisition\nsystem that indicated but did not alert the operator of a leak for more than 11 hours.\nLessons Learned\nPipeline operators must manage and address all threats to pipeline integrity,\nincluding those from weather events and geohazards. After the accident, Third Coast\ndeveloped a program to monitor the MPOG pipeline system and collet grip fittings for\npossible pipe movement and to test and confirm the function of the fitting seals. PHMSA\nis overseeing modifications to Third Coast’s risk management program to include\nevaluations when mudflows or other geohazards occur.\nIn this accident, uncertainty about the accuracy of SCADA data led to a delayed\nshutdown of the pipeline. The NTSB has investigated other accidents in which\ncontrollers, faced with control system information indicating an anomaly, have failed to\nshut down pipelines. In Marshall, Michigan, in 2010, controllers’ flawed interpretations of\nsystem data and alarms contributed to the delayed shutdown of a pipeline, which\n12 Title 49 CFR 192.327 specifies the burial requirements for an offshore pipeline in shallow water\n(200 feet deep or less). In water between 12 and 200 feet deep, the pipe must be installed so the top of the\npipe is below the natural bottom, or seafloor.\n8\n\n<<<PAGE 9>>>\n\nPipeline Investigation Report\nPIR-25-02\nreleased 843,000 gallons of crude oil into wetlands.\n13 More recently, in 2021, pipeline\ncontrollers in San Pedro Bay, near Huntington Beach, California, did not shut down a\nleaking underwater crude oil pipeline for 14 hours after incorrectly determining that leak\nalarms were false.\n14\nLeak detection tools help reduce uncertainty for controllers interpreting abnormal\ncontrol system data. After the accident, Third Coast reported that it is implementing a\nleak detection software system specifically for MPOG and has added a leak detection\nalarm to its SCADA system, with a tolerance level based on historical flow patterns. The\ncompany also added information on leak detection to its control center operational\nprocedures and related training.\n13 NTSB. 2012. Enbridge Incorporated Hazardous Liquid Pipeline Rupture and Release, Marshall,\nMichigan, July 25, 2010. PAR-12/01. Washington, DC: NTSB.\n14 NTSB. 2024. Anchor Strike of Underwater Pipeline and Eventual Crude Oil Release, San Pedro Bay,\nNear Huntington Beach, California, October 1, 2021. MIR-24/01. Washington, DC: NTSB.\n9\n\n<<<PAGE 10>>>\n\nPipeline Investigation Report\nPIR-25-02\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\nPLD24FR001. 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\n10","truncated":false,"body_characters":23224}