{"operation":"document","citation":"DCA08MP001","title":"Rupture of Hazardous Liquid Pipeline with Release and Ignition of Propane","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"2026-01-30","effective_on":"2007-11-01","summary":"Accident. in Matherville, MS, USA. on 2007-11-01. Dixie Pipeline Company. Leak/explosion/fire","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-dca08mp001.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-dca08mp001.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-dca08mp001","source_url":"https://www.ntsb.gov/investigations/Pages/DCA08MP001.aspx","body":"NTSB investigation DCA08MP001.\n\nEvent Type: Accident\n\nEvent Date: 2007-11-01\n\nEvent City: Matherville\n\nEvent State Or Region: MS\n\nEvent Country: USA\n\nPipeline Operator: Dixie Pipeline Company\n\nPipeline Type: Hazardous Liquid - Regulated\n\nAccident Type: Leak/explosion/fire\n\nCompletion Status: Completed\n\nReport Number: PAR-09-01\n\nProbable cause: The National Transportation Safety Board determines that the probable cause of the November 1, 2007, rupture of the liquid propane pipeline operated by Dixie Pipeline Company near Carmichael, Mississippi, was the failure of a weld that caused the pipe to fracture along the longitudinal seam weld, a portion of the upstream girth weld, and portions of the adjacent pipe joints.\n\nTier1Name: System operating\n\nTier2Name: Fire/explosion (post-release)\n\nTier1Name: System operating\n\nTier2Name: Pipe structural malfunction/failure\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: Federal agency\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - Federal agency\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Oversight\n\nFinding Modifier Name: Other institution/organization\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Oversight - Other institution/organization\n\nFinding Tier1Name: Personnel\n\nFinding Tier2Name: Experience/knowledge\n\nFinding Tier3Name: Training\n\nFinding Tier4Name: (general)\n\nFinding Modifier Name: State/Local government personnel\n\nFinding Report Text: Personnel - Experience/knowledge - Training - State/Local government 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\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 1, 2007, at 10:35:02 a.m. central daylight time, a 12-inch-diameter pipeline segment operated by Dixie Pipeline Company was transporting liquid propane at about 1,405 pounds per square inch, gauge, when it ruptured in a rural area near Carmichael, Mississippi. The resulting gas cloud expanded over nearby homes and ignited, creating a large fireball that was heard and seen from miles away. About 10,253 barrels (430,626 gallons) of propane were released. As a result of the ensuing fire, two people were killed and seven people sustained minor injuries. Four houses were destroyed, and several others were damaged. About 71.4 acres of grassland and woodland were burned. Dixie Pipeline Company reported that property damages resulting from the accident, including the loss of product, were $3,377,247.\n\nWhat We Found\nThe probable cause of the November 1, 2007, rupture of the liquid propane pipeline operated by Dixie Pipeline Company near Carmichael, Mississippi, was the failure of a weld that caused the pipe to fracture along the longitudinal seam weld, a portion of the upstream girth weld, and portions of the adjacent pipe joints.\n\nWhat We Recommended\nAs a result of the investigation of this accident, the National Transportation Safety Board makes recommendations to the Pipeline and Hazardous Materials Safety Administration, the Dixie Pipeline Company, the American Petroleum Institute, and the Clarke County Board of Supervisors.\n\nPAR-09-01\n<<<PAGE 1>>>\n\nRupture of Hazardous Liquid Pipeline\nWith Release and Ignition of Propane\nCarmichael, Mississippi\nNovember 1, 2007\nAccident Report\nNTSB/PAR-09/01\nPB2009-916501\nNational\nTransportation\nSafety Board\n\n<<<PAGE 2>>>\n\n\n\n<<<PAGE 3>>>\n\nNTSB/PAR-09/01\nPB2009-916501\nNotation 7979A\nAdopted October 14, 2009\nPipeline Accident Report\nRupture of Hazardous Liquid Pipeline\nWith Release and Ignition of Propane\nCarmichael, Mississippi\nNovember 1, 2007\nNational\nTransportation\nSafety Board\n490 L’Enfant Plaza, S.W.\nWashington, D.C. 20594\n\n<<<PAGE 4>>>\n\nNational Transportation Safety Board. 2009. Rupture of Hazardous Liquid Pipeline With Release and Ignition\nof Propane, Carmichael, Mississippi, November 1, 2007. Pipeline Accident Report NTSB/PAR-09/01.\nWashington, DC.\nAbstract: On November 1, 2007, at 10:35:02 a.m. central daylight time, a 12-inch-diameter pipeline segment\noperated by Dixie Pipeline Company was transporting liquid propane at about 1,405 pounds per square inch, gauge,\nwhen it ruptured in a rural area near Carmichael, Mississippi. The resulting gas cloud expanded over nearby homes\nand ignited, creating a large fireball that was heard and seen from miles away. About 10,253 barrels (430,626\ngallons) of propane were released. As a result of the ensuing fire, two people were killed and seven people\nsustained minor injuries. Four houses were destroyed, and several others were damaged. About 71.4 acres of\ngrassland and woodland were burned. Dixie Pipeline Company reported that property damage resulting from the\naccident, including the loss of product, was $3,377,247.\nThe safety issues identified in this accident are the failure mechanisms and safety of low-frequency electric\nresistance welded pipe, the adequacy of Dixie Pipeline Company’s public education program, the adequacy of\nfederal pipeline safety regulations and oversight exercised by the Pipeline and Hazardous Materials Safety\nAdministration of pipeline operators’ public education and emergency responder outreach programs, and\nemergency communications in Clarke County, Mississippi.\nAs a result of the investigation of this accident, the National Transportation Safety Board makes recommendations\nto the Pipeline and Hazardous Materials Safety Administration, the Dixie Pipeline Company, the American\nPetroleum Institute, and the Clarke County Board of Supervisors.\nThe National Transportation Safety Board is an independent federal agency dedicated to promoting aviation, railroad, highway,\nmarine, pipeline, and hazardous materials safety. Established in 1967, the agency is mandated by Congress through the\nIndependent Safety Board Act of 1974 to investigate transportation accidents, determine the probable causes of the accidents,\nissue safety recommendations, study transportation safety issues, and evaluate the safety effectiveness of government agencies\ninvolved in transportation. The NTSB makes public its actions and decisions through accident reports, safety studies, special\ninvestigation reports, safety recommendations, and statistical reviews.\nRecent publications are available in their entirety on the Internet at <http://www.ntsb.gov>. Other information about available\npublications 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, DC 20594\n(800) 877-6799 or (202) 314-6551\nNTSB publications may be purchased, by individual copy or by subscription, from the National Technical Information Service.\nTo purchase this publication, order report number PB2009-916501 from:\nNational Technical Information Service\n5285 Port Royal Road\nSpringfield, Virginia 22161\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 or use of\nNTSB reports related to an incident or accident in a civil action for damages resulting from a matter mentioned in the report.\n\n<<<PAGE 5>>>\n\nNTSB Pipeline Accident Report\nContents\nFigures .............................................................................................................................................v\nAcronyms and Abbreviations ..................................................................................................... vi\nExecutive Summary .................................................................................................................... vii\nFactual Information .......................................................................................................................1\nAccident Synopsis ............................................................................................................................1\nAccident Narrative ...........................................................................................................................1\nEmergency Response .......................................................................................................................4\nAccident Site ....................................................................................................................................6\nOn-Scene Response ..................................................................................................................7\nEvacuations ...............................................................................................................................9\nConclusion of On-Scene Response ...........................................................................................9\nInjuries ...........................................................................................................................................10\nDamages .........................................................................................................................................10\nPostaccident Inspections ................................................................................................................10\nPipeline ...................................................................................................................................10\nSurrounding Area ....................................................................................................................12\nPipeline Controller .........................................................................................................................12\nPipeline Information ......................................................................................................................13\nDesign and Construction .........................................................................................................13\nOperating History ...................................................................................................................13\nPrevious In-service Pipeline Failures .....................................................................................14\nPreaccident Hydrostatic Pressure Tests ..................................................................................15\nIn-Line Inspection Information ...............................................................................................16\nTests and Research .........................................................................................................................20\nMetallurgical Examination of Accident Pipe .........................................................................20\nFinite Element Analysis ..........................................................................................................23\nERW Pipeline.................................................................................................................................25\nPerformance of Low-Frequency ERW Pipe ...........................................................................25\nFederal Oversight and Studies ................................................................................................26\nPostaccident Actions ......................................................................................................................28\nPHMSA ...................................................................................................................................28\nDixie Pipeline .........................................................................................................................29\nPostaccident Emergency Response Debriefing ......................................................................30\nPipeline Operator Public Education Programs ..............................................................................30\nRegulations and Standards ......................................................................................................30\nDixie’s Public Education Program .........................................................................................31\nClarke County Emergency Management and Communications ....................................................36\nEmergency Management ........................................................................................................36\nEmergency Communications ..................................................................................................36\niii\n\n<<<PAGE 6>>>\n\nNTSB Pipeline Accident Report\nAnalysis .........................................................................................................................................38\nExclusions ......................................................................................................................................38\nFracture of the Pipeline ..................................................................................................................39\nSafety and Performance of ERW Pipe ...........................................................................................41\nPipeline Operator Public Education Programs ..............................................................................43\nPublic Awareness Program .....................................................................................................44\nOutreach Program to Emergency Responders ........................................................................44\nClarke County Emergency Communications .................................................................................46\nPreparedness of Clarke County 911 Dispatch Center .............................................................46\nEmergency Radio Communications .......................................................................................47\nConclusions ...................................................................................................................................49\nFindings..........................................................................................................................................49\nProbable Cause...............................................................................................................................50\nRecommendations ........................................................................................................................51\nAppendix A ...................................................................................................................................53\nInvestigation ...................................................................................................................................53\nAppendix B ...................................................................................................................................54\nAccident Timeline ..........................................................................................................................54\niv\n\n<<<PAGE 7>>>\n\nNTSB Pipeline Accident Report\nFigures\nFigure 1. Map of Dixie pipeline. .................................................................................................... 2\nFigure 2. Aerial view of fire from pipeline rupture showing nearby destroyed houses. ............... 3\nFigure 3. Ruptured pipe at Carmichael looking southwest. (Soil has been removed from\naround pipe to facilitate on-site examination.) ............................................................................. 11\nFigure 4. Downstream end of rupture. ......................................................................................... 20\nFigure 5. Ruptured pipe. .............................................................................................................. 21\nFigure 6. Schematic drawing of accident pipe identifying welds and showing fracture\nfeatures of interest. ........................................................................................................................ 22\nv\n\n<<<PAGE 8>>>\n\nNTSB Pipeline Accident Report\nAcronyms and Abbreviations\nAPI American Petroleum Institute\nAPI RP 1162 API Recommended Practice 1162\nCFR Code of Federal Regulations\nCVFD Carmichael Volunteer Fire Department\nDixie Dixie Pipeline Company\nDOT U.S. Department of Transportation\nEnterprise Enterprise Products Operating\nERW Electric resistance welded\nGE General Electric\nHunt Hunt Crude Oil Supply Company\nMagpie Magpie Systems Inc.\nNTSB National Transportation Safety Board\nParadigm Paradigm Alliance, Inc.\nPHMSA Pipeline and Hazardous Materials Safety Administration\npsi pounds per square inch\npsig pounds per square inch, gauge\nSCADA Supervisory control and data acquisition\nStork Stork Metallurgical Consultants\nvi\n\n<<<PAGE 9>>>\n\nNTSB Pipeline Accident Report\nExecutive Summary\nOn November 1, 2007, at 10:35:02 a.m. central daylight time, a 12-inch-diameter\npipeline segment operated by Dixie Pipeline Company was transporting liquid propane at about\n1,405 pounds per square inch, gauge, when it ruptured in a rural area near Carmichael,\nMississippi. The resulting gas cloud expanded over nearby homes and ignited, creating a large\nfireball that was heard and seen from miles away. About 10,253 barrels (430,626 gallons) of\npropane were released. As a result of the ensuing fire, two people were killed and seven people\nsustained minor injuries. Four houses were destroyed, and several others were damaged. About\n71.4 acres of grassland and woodland were burned. Dixie Pipeline Company reported that\nproperty damages resulting from the accident, including the loss of product, were $3,377,247.\nThe National Transportation Safety Board determines that the probable cause of the\nNovember 1, 2007, rupture of the liquid propane pipeline operated by Dixie Pipeline Company\nnear Carmichael, Mississippi, was the failure of a weld that caused the pipe to fracture along the\nlongitudinal seam weld, a portion of the upstream girth weld, and portions of the adjacent pipe\njoints.\nThe following safety issues were identified as a result of the investigation of this\naccident:\n• The failure mechanisms and safety of low-frequency electric resistance welded pipe,\n• The adequacy of Dixie Pipeline Company’s public education program,\n• The adequacy of federal pipeline safety regulations and oversight exercised by the\nPipeline and Hazardous Materials Safety Administration of pipeline operators’ public\neducation and emergency responder outreach programs, and\n• Emergency communications in Clarke County, Mississippi.\nSafety recommendations to the Pipeline and Hazardous Materials Safety Administration,\nthe Dixie Pipeline Company, the American Petroleum Institute, and the Clarke County Board of\nSupervisors are included in the report.\nvii\n\n<<<PAGE 10>>>\n\nNTSB\nPipeline Accident Report\n\n<<<PAGE 11>>>\n\nNTSB Pipeline Accident Report\nFactual Information\nAccident Synopsis\nOn November 1, 2007, at 10:35:02 a.m.1 central daylight time,2 a 12-inch-diameter\npipeline segment operated by Dixie Pipeline Company (Dixie) was transporting liquid propane at\nabout 1,405 pounds per square inch, gauge (psig), when it ruptured in a rural area near\nCarmichael, Mississippi. The resulting gas cloud expanded over nearby homes and ignited,\ncreating a large fireball that was heard and seen from miles away. About 10,253 barrels\n(430,626 gallons) of propane were released. As a result of the ensuing fire, two people were\nkilled and seven people sustained minor injuries. Four houses were destroyed, and several others\nwere damaged. About 71.4 acres of grassland and woodland were burned. Dixie reported that\nproperty damages resulting from the accident, including the loss of product, were $3,377,247.\nAccident Narrative\nAt 10:35:02 a.m. central daylight time, Dixie’s 12-inch-diameter propane pipeline\nsegment ruptured about 2,650 feet downstream of Carmichael Pump Station near Carmichael,\nMississippi. The map in figure 1 shows the route of the entire pipeline—from Mont Belvieu,\nTexas, to Apex, North Carolina—which comprises various sizes of pipe from several pipe\nmanufacturers. The 12-inch-diameter pipeline segment starts on the west side of the Mississippi\nRiver near Erwinville, Louisiana, and continues eastward about 395 miles to Opelika, Alabama.\nYellow Creek Pump Station is 19.28 miles upstream of Carmichael Station. The first pump\nstation downstream of Carmichael is Butler Station, which is 18.3 miles east of Carmichael.\n1 The times associated with events indicated in hours:minutes:seconds are from either the Supervisory Control\nand Data Acquisition (SCADA) system or the 911 system.\n2 All times in this report are central daylight time except where otherwise noted.\n1\n\n<<<PAGE 12>>>\n\nNTSB Pipeline Accident Report\nFigure 1. Map of Dixie pipeline.\nThe Dixie pipeline is owned by Enterprise Products Operating (Enterprise); the controller\nfor the accident pipeline was located at Enterprise’s liquid pipeline Supervisory Control and Data\nAcquisition (SCADA) Control Center in Houston, Texas. The first indication of a problem was\nwhen the SCADA control panel displayed sequential discharge pressure measurements that\nindicated a large change in pressure at Carmichael Pump Station. At 10:35:07 a.m., the display\nshowed a discharge pressure of 1,079 psig; at 10:35:13 a.m., the discharge pressure was\n154 psig, indicating a large, sudden drop in pipeline pressure. Additionally, the display showed\nthat Carmichael Station’s unit 2 pump had shut down because of low suction pressure. At\n10:35:46 a.m., the SCADA display indicated that the rate-of-change in pressure at Butler Station,\nthe next station downstream from Carmichael, was starting to decrease. Also, at 10:35:50 a.m.,\nthe SCADA display indicated that the rate-of-change in pressure at Yellow Creek Station, the\nfirst station upstream of Carmichael Station, was starting to come down.\nWhen the pipeline ruptured at 10:35:02 a.m., liquid propane was released and\ninstantaneously began to vaporize and form a low-lying propane gas cloud over the area. The\npropane gas did not ignite immediately; it ignited about 7 1/2 minutes later, at 10:42:30 a.m.\nWitnesses miles away reported seeing and hearing a large fireball and heavy black smoke over\nthe area. The fire extended about 950 feet southwest and about 1,250 feet south of the rupture\nsite. (See figure 2.) The fire fueled by the residual propane gas escaping from the pipeline\n2\n\n<<<PAGE 13>>>\n\nNTSB Pipeline Accident Report\ncontinued to burn at the ruptured pipe joint3 until the following day, when the fire at the pipe\nextinguished itself after flow control valves on both sides of the rupture were closed.\nFigure 2. Aerial view of fire from pipeline rupture showing nearby destroyed houses.\nAt the time of the rupture, the flow of propane had increased from 5,952 barrels per hour\nto 7,354 barrels per hour. At 10:36:25 a.m., a little more than 1 minute after the SCADA display\nof the sudden pressure reduction, the controller decided that there was a leak in the Carmichael\nStation area, and he began shutting down the pipeline to reduce the amount of product released.\nAt 10:37:12 a.m., the controller started the unit 1 pump at Butler Station (downstream of the\nrupture) to pull product away from the rupture area. About 10:38 a.m., the controller started\ncalling field personnel from Hattiesburg and Demopolis Pump Stations to respond to the release.\nAbout 10:41 a.m., a person in a house in the 8500 block of County Road 630 called the\ntoll-free emergency number for Dixie to report an explosion and smoke near her house. Dixie’s\nSCADA controller on duty recognized this report as indicating a product release from a pipeline\nin the Carmichael area.\nAt 10:46 a.m., the Dixie pipeline controller in Houston received a telephone call in which\nthe caller described four explosions, fire 200 feet in the air, and two columns of white and black\nsmoke. The caller said these were in “the area where a crude oil pipeline owned by Hunt [Crude]\n3 A joint is a single length of pipe; the accident joint was about 52 feet long.\n3\n\n<<<PAGE 14>>>\n\nNTSB Pipeline Accident Report\nOil [Supply Company] (Hunt) crosses the Dixie pipeline.” The controller then directed a\ncontractor in the Carmichael area to go to the site. At 10:48 a.m., a Hunt employee told the\ncontroller that the Hunt pipeline had been shut down and blocked off in the area of the release.\nAt 10:49:51 a.m., the Dixie pipeline controller telephoned Clarke County Central\nDispatch to provide notification of a pipeline leak in the Carmichael Station area. The controller\nwas told that Clarke County officials were already aware of an event near that location and had\ndispatched trucks to the scene from several fire departments. The controller continued to isolate\nthe rupture site by issuing commands through SCADA to close the remotely controlled block\nvalves at the Butler and Carmichael Stations starting at 10:52:37 a.m. By 12:36 p.m., field\ntechnicians had closed the nearest manually controlled block valves, thereby completing the\nshutdown and isolation of the leaking section of the pipeline.\nWeather conditions at the National Weather Service station in Meridian, Mississippi,\naround the time of the accident were reported as a clear sky (that is, no precipitation), a surface\nvisibility of 10 miles, wind from the north-northeast about 7 mph with no significant wind gusts,\nand a ground level atmospheric temperature of 69° F. Sunrise was at 6:37 a.m. and sunset at\n4:49 p.m.\nEmergency Response\nThe first call received at Clarke County Central Dispatch, which operates the county’s\n911 emergency call center, came in at 10:39:56 a.m. Two operators were on duty at the time. The\ncall was from a person calling from a house at 4195 County Road 621. The caller reported that a\ngas explosion had occurred somewhere around the area and that smoke and gas surrounded the\nhouse. When asked if there was fire, the caller said that she did not see any fire but she saw white\ngas and smelled gas. The 911 operator told the caller that an emergency responder would be sent.\nThe operator did not tell the caller to get out of the house and run away from the smoke. The call\nlasted 1 minute 20 seconds. The house at this address was subsequently identified as the house in\nwhich one of the two fatalities was discovered. At 10:40:13 a.m., during the first 911 call, the\nsecond 911 operator received a telephone call from a caller in a house in the 4300 block of\nCounty Road 621, about 600 feet south of the house where the first 911 call had originated. The\ncaller reported that an explosion had occurred and he could see smoke when he walked out to the\nroad. The call lasted 1 minute 33 seconds and concluded at 10:41:46 a.m. Clarke County Central\nDispatch subsequently received numerous additional calls reporting the incident.\n4\n\n<<<PAGE 15>>>\n\nNTSB Pipeline Accident Report\nAbout 10:42 a.m., after receiving the first two 911 calls, Clarke County Central Dispatch\nplaced a radio dispatch page to the Carmichael Volunteer Fire Department (CVFD) to respond to\nthe house at 4195 County Road 621. The Clarke County Central Dispatch operating personnel\ndid not know at that time that their fire department radio signal repeater4 did not transmit the\npage to the CVFD. Later, it was determined that the repeater system did not send a signal\nbecause it had been disabled during routine cleaning in the Clarke County Central Dispatch\nfacility when a floor mop had accidentally dislodged the connector fittings of several\ncommunication cables about 90 minutes before the accident.\nThe assistant chief of the CVFD was at work about 1/4 mile from the CVFD fire station\nwhen, about 10:43 a.m., he heard the sound of a distant explosion. According to the assistant\nchief, the sound was followed shortly thereafter by the sound of a second explosion and perhaps\nthe sound of a third explosion. About 10 to 15 seconds later, he saw a large plume and a cloud of\nheavy black smoke rising above the trees. The assistant chief immediately began mobilizing\nCVFD fire apparatus and personnel to the scene.\nAt 10:42:50 a.m., a caller at a construction site on a road north of Waynesboro, used a\ncellular telephone to call Wayne County, Mississippi, 911. The caller reported that an explosion\nhad occurred northeast of his location. In a postaccident interview, this caller indicated that he\nhad placed the 911 call about 20 seconds after he heard the sound of what appeared to be an\nexplosion that occurred in the distance and after he saw a large plume and a cloud of heavy black\nsmoke rising above the trees and moving northeast from his location. Following another 911 call\nthat was received about 17 seconds after the 10:42:50 phone call, Wayne County 911 sent a\nWayne County deputy sheriff to verify the incident location, and then, under a mutual aid\nagreement with Clarke County, dispatched Wayne County fire and rescue units to the scene.\nAbout 10:44 a.m., because Clarke County Central Dispatch had not received a response\nfrom the CVFD acknowledging the page that had been placed about 2 minutes earlier, Clarke\nCounty Central Dispatch sent a second page, this time to the Theadville Volunteer Fire\nDepartment to respond to 4195 County Road 621.5 Clarke County Central Dispatch was still\nunaware at that time that the radio signal repeater was not functioning and the page to the\nTheadville fire department also had not been transmitted.\nThe Clarke County sheriff was at his residence about 20 miles from the accident site\nwhen about 10:44 a.m. he received a telephone call from Clarke County Central Dispatch asking\nwhether there were any pipelines near County Roads 630 and 621, because a 911 call had just\nreported an explosion in that area. The sheriff responded that there was a pipeline in the\nCarmichael area. During postaccident interviews, the sheriff stated that he had been casually\nlistening to his service radio just before this phone call, and there had not been any radio traffic\n4 A radio signal repeater is a combination of a radio receiver and a radio transmitter that receives a radio signal\nand retransmits it at a higher level or higher power to relay radio signals across a wider area.\n5 In accordance with Clarke County Central Dispatch operations protocol, a page is to be acknowledged by the\ndepartment receiving the page. If no acknowledgement is received within about 2 minutes, the next closest fire\ndepartment is paged and directed to respond. Clarke County Central Dispatch is to continue to page and dispatch a\nsequence of fire departments until an acknowledgement is received.\n5\n\n<<<PAGE 16>>>\n\nNTSB Pipeline Accident Report\nabout an incident occurring in the Carmichael area. Clarke County Central Dispatch told the\nsheriff that two units (deputies) had been dispatched to that location and the CVFD had been\npaged to respond. The sheriff then told Clarke County Central Dispatch that he would monitor\nthe radio closely for updates.\nAbout 10:48 a.m., Clarke County Central Dispatch had not received a response from the\nTheadville Volunteer Fire Department acknowledging the page that had been placed about\n4 minutes earlier. Clarke County Central Dispatch then repeated the page, this time to the\nTheadville, Quitman, and Carmichael Volunteer Fire Departments and the Desoto Fire\nDepartment.\nAbout 10:55 a.m., the Clarke County Central Dispatch dispatcher had not received any\nresponses acknowledging his pages to the four fire departments, and he began to suspect that the\nfire department radio signal repeater was not working and that none of the pages to the fire\ndepartments had been transmitted or received. Therefore, following the Clarke County Central\nDispatch backup communication plan, the dispatcher switched to the Clarke County Sheriff’s\nDepartment radio signal repeater, which was operating correctly.6\nConcurrently, the Clarke County sheriff continued monitoring his service radio and did\nnot hear any responses to the Clarke County Central Dispatch pages. The sheriff suspected that\nthe fire department radio signal repeater had failed to transmit, but he was unable to contact\nClarke County Central Dispatch because of the range limitations of his service radio.\nAccordingly, about 10:55 a..m., he contacted a deputy who was within transmission range and\ndirected the deputy to notify Clarke County Central Dispatch that the radio signal repeater\nappeared not to be working and to use the Clarke County Sheriff’s Department radio signal\nrepeater to establish radio communications with the fire and rescue agencies. The sheriff then\ndrove his personal vehicle to the site.\nAccident Site\nThe pipeline rupture occurred in a cattle pasture in a relatively unpopulated area in\nCarmichael, Mississippi, which is an unincorporated section of Clarke County. The site was\noccupied by livestock at the time of the rupture. Clarke County has a population of 21,979 and\nan area of about 416 square miles. The accident site is about 12 miles southeast of Quitman, the\nClarke County seat, about 3 miles north of the Wayne County line, and about 3 1/2 miles west of\nthe Alabama-Mississippi state line. (See figure 1.)\nAbout 200 residents live within a 1-mile radius of the accident site. The pipeline right-of-\nway in this area is oriented generally southwest-northeast. The ground rises slightly to the east\nand west of the rupture site, such that the rupture site is located at the base of a shallow valley.\nThe pipeline is flanked on both sides by uncultivated fields and wooded lots. A 100-foot-wide\n6 The Clarke County Fire Department and the Clarke County Sheriff Department can transmit and receive on\neach other’s radio signal frequency.\n6\n\n<<<PAGE 17>>>\n\nNTSB Pipeline Accident Report\nzone in the middle of the right-of-way had been cleared of trees and shrubs. Federally required\nwarning markers were located along the right-of-way to alert the public to the pipeline’s presence\nand location, the product being transported, the identification of the owner/operator, and\nemergency contact information.\nThe buried Dixie pipeline crosses several feet above an 8-inch-diameter hazardous liquid\n(crude oil) pipeline operated by Hunt. The two pipelines cross about 170 feet east of the\nnortheastern end of the ruptured pipe joint. Hunt representatives told National Transportation\nSafety Board (NTSB) investigators that the Hunt pipeline was neither involved with nor affected\nby the rupture of Dixie’s liquid propane pipeline.\nThe Dixie pipeline passes beneath County Road 621 about 900 feet southwest of the\nruptured pipe joint. A cluster of six houses is located about 500 feet southwest of the rupture site,\nwith an additional cluster of five houses located a short distance farther south. All 11 houses are\non County Road 621.\nOn-Scene Response\nUpon hearing the explosion and seeing the fireball and heavy black smoke, at 10:43 a.m.,\nthe CVFD assistant chief drove his personal vehicle in the direction of the smoke to see the\nsituation firsthand. While en route, the assistant chief spoke to the CVFD chief using his\npersonal cell phone, which had a short-range wireless communication feature similar to a walkie-\ntalkie. The two conferred briefly about what had occurred, made a preliminarily identification of\nthe location sufficient to direct CVFD resources to the general area of the accident, and agreed to\nmobilize the CVFD in response to the accident. The assistant chief then drove toward the CVFD\nfire station and used the short-range wireless feature on his cell phone to tell several other CVFD\npersonnel what had occurred and to direct resources (two tanker trucks) to the scene.\nA few moments later, the assistant chief and the CVFD captain arrived simultaneously at\nthe CVFD fire station. They left immediately in a pumper truck and unsuccessfully attempted by\nradio to contact Clarke County Central Dispatch to report that they were en route to the scene.\nAbout 10:55 a.m. the assistant fire chief and the captain received word that the fire department\nradio signal repeater had apparently malfunctioned, and in accordance with the back-up\ncommunication plan, on-scene fire and rescue units were to switch to the Sheriff’s Department\nradio frequency that used the sheriff’s department radio signal repeater.\nAbout 10:56 a.m., Clarke County Central Dispatch received a message from one of the\non-scene deputy sheriffs reporting that the CVFD pumper truck with the CVFD assistant chief\nand the CVFD captain aboard, had just arrived at the scene at the intersection of County Roads\n620 and 621, that the CVFD pumper truck was the first firefighting apparatus at the scene, that\nthe CVFD had already begun to dispatch additional CVFD resources to the scene, and that the\ninstruction to switch to the sheriff’s department radio frequency had been received by the CVFD.\n7\n\n<<<PAGE 18>>>\n\nNTSB Pipeline Accident Report\nAbout 11:15 a.m., the Clarke County sheriff arrived at the intersection of County Roads\n620 and 621, which later became the incident command post location. As prescribed by the\nClarke County emergency management plan, the sheriff proceeded to implement an incident\ncommand process and assumed the role of incident commander. Later the incident command\nstructure was elevated to a unified command system.\nWhen the assistant fire chief and the fire captain approached the scene and saw a\nsubstantial fire and a cloud of heavy black smoke, they strongly suspected that the likely source\nof the fire was the propane pipeline buried underneath the cattle pasture. At the time, they did not\nknow the extent of the fire and the number and locations of residents who might be endangered.\nBoth recognized that the houses on County Road 621 would probably be in the greatest danger,\nso they drove the fire truck toward those houses.\nThe CVFD assistant chief stated during postaccident interviews that although he was\naware that the pipeline transported highly flammable propane, the cause of what appeared to be a\nsubstantial rupture and product release and a fully involved fire, and the extent of damage to the\nrest of the pipeline, were not apparent to him at the time. Accordingly, the assistant chief drove\nthe pumper truck on County Road 621 and stopped just short of the location where the Dixie\npipeline passed beneath the road. The pumper truck was initially staged at that location, which\nbecame the initial forward command staging location. Additional fire and rescue units from other\nlocal fire departments were later staged at the parking lot of the Baptist church at the intersection\nof County Roads 630 and 632. Responding units from Alabama were staged on County Road 630\nat the Alabama state line, and responding Wayne County resources were staged on County Road\n620 at the Wayne County line.\nWhen the assistant fire chief and the fire captain performed their initial assessment of the\nsituation, they observed several civilians, whom they assumed to be residents of County Road\n621 or 620, assisting others to leave the scene. Several sheriff’s deputies arrived about that time,\nand they also began to assist civilians to leave the scene and to establish motor vehicle traffic\ncontrol at the west end of County Road 621. A short distance to the east, CVFD personnel\nobserved the burned remains of several houses and several other houses that were fully engulfed\nin flames and thus were deemed not salvageable. Fire had extensively charred the trees and","truncated":true,"body_characters":157908}