Failure Report- Southern Star Central Gas Pipeline, Inc. 6/30/05

Page 1Official PDFDOT US Department of Transportation PHMSA Pipeline and Hazardous Materials Safety Administration OPS Office of Pipeline Safety Central Region Principal Investigator James Bunn Region Director David Barrett Date of Report 5/25/2012 Subject Failure Investigation Report – Southern Star Central Rupture, Overpressure in KS Operator, Location, & Consequences Date of Failure 6/30/2005 Commodity Released Natural Gas City/County & State Lawrence/Douglas County, Kansas OpID & Operator Name 31711 Southern Star Central Gas Pipeline, Inc. Unit # & Unit Name 15193 Tonganoxie Area SMART Activity # 116063 Milepost / Location Pipeline Station 681+69 (Series 130 Station) Type of Failure Rupture due to Operator Error Fatalities 0 Injuries 0 Description of area impacted Rural Area, Class 1, Non HCA Property Damage $192,163#

Page 2Failure Investigation Report – Southern Star Central Rupture Due to Overpressure Failure Date 6/30/2005 Executive Summary On June 30, 2005, Southern Star Central Gas Pipeline (SSCGP) Control Center received a SCADA system alarm at 7:52 pm. This alarm indicated electrical and communications power loss and was the result of a lightning strike at Ottawa Station. As a result, the programmable logic controller (PLC) for Ottawa Station powered down. When power was restored, the PLC placed the station in local control, and automatically moved valves and set points to the last known positions. At 7:53 pm, the Control Center received a separate alarm that indicated the maximum allowable operating pressure (MAOP) for the Topeka (ES 20-inch) pipeline had been exceeded. At 8:16 pm an SSCGP employee who worked in the Tonganoxie, KS District was contacted by a family member who reported a potential pipeline rupture south of Lawrence, KS. The Control Center had not received any loss in pressure as of 8:20 pm. The failure was confirmed by Douglas County Kansas Dispatch at 8:25 pm and was determined to be located between the towns of Lawrence and Ottawa, approximately three miles south of Lawrence, KS. The National Response Center (NRC) was contacted at 9:56 pm (CT) and the operator provided a call to the PHMSA Central Region at 10:00 pm. As designed, when power was lost at the Ottawa Station, the working regulator on the ES 20-inch line failed in the open position. The monitor regulator however failed to operate (this regulator was designed to protect the ES 20-inch pipeline from overpressure in the event of any type of malfunction of the working regulator). With the working monitor in the open position and the monitor regulator not operational, the ES 20-inch pipeline was exposed to a pressure above the maximum allowable operating pressure (MAOP). The established MAOP was 450 psig. The maximum pressure experienced at Ottawa Station was 680 psig. At approximately 8:15 pm, the ES-20-inch line ruptured in an agricultural field about 6.4 miles downstream of the Ottawa station. The subsequent metallurgical investigation determined that the overpressure condition resulted in higher than usual membrane stresses in the pipeline and that “the failure occurred just outside of the area of the lap-weld seam, in steel that was free of process or fabrication related defects.” No fatalities or injuries occurred as a result of the rupture and there was no fire or explosion. The rupture occurred in a Class 1 rural area and was not in an HCA. Four individuals were evacuated by an emergency responder as a precautionary measure and twelve domestic customers were without gas service for two days. The operator reported the total cost of the accident as $192,163. It was later determined that the monitor regulator failed to operate due to the fact that the pneumatic controller supply valve was in a closed position. The supply valve was apparently left closed by a technician who had been performing maintenance activities on the monitor regulator on April 26, 2005. System Details The SSCGP system consists of over 6,000 miles of natural gas transmission pipelines in the Midwest region of the United States. The system serves several major market areas including the Kansas town of Wichita, the greater Kansas City area (KS and MO) and St. Louis, Missouri. The ES 20-inch pipeline runs north from Ottawa to Lawrence Kansas, a distance of approximately 28 miles. This pipeline is fed through two regulator stations which are located at the Ottawa Station. The pipeline was constructed in 1929 and the portion of the line that failed consisted of 20-inch diameter line pipe with a wall thickness of 0.312 inch. The pipe was manufactured by Spang-Chalfont Page 2 of 5#

Page 3Failure Investigation Report – Southern Star Central Rupture Due to Overpressure Failure Date 6/30/2005 (later known as National Supply and became part of US Steel) using the furnace lap weld process. The grade of pipe was unknown but assumed to be 24,000 psi. The pipeline was joined by the oxyacetylene welding process. The girth welds had not been radiographed during construction. The depth of cover at the point of failure was 24 inches. The MAOP of the line (450 psig) was established based on the highest actual operating pressure of the pipeline during the previous five years prior to July 1, 1970. The pressure at the time and location of the failure was determined to be between 520 psig and 680 psig. The section of the line that contained the rupture had not been hydrostatically tested or inspected with internal inspection devices prior to the failure. Events Leading up to the Failure On June 30, 2005 a lightning strike at the SSCGP Ottawa Station disrupted the electrical power and the communication systems at the station. The lightning strike apparently blew a fuse for the electrical circuit that provided power to the PLC that controlled multiple working pressure regulators. The PLC did not remain on battery power when the main power failed. The loss of power caused the regulators to lose diaphragm pressure to the respective valve actuators. This caused the regulators to fail in the open position. Each of the working regulators relied on an individual monitor regulator as an overpressure protection device. Each of the monitor regulators performed as designed except for monitor regulator 1137 RM, which should have provided overpressure protection to the ES 20-inch line. The failure of the 1137 RM regulator led to an overpressure condition in the ES-20- inch pipeline and the subsequent rupture of the pipe (approximately ½ mile south of Douglas County Road 460 on East 1400 Road). Electrical surge suppression had not been implemented and unshielded instrumentation cable had been used. Transmitters had not been electrically isolated from the piping. Emergency Response The SSCGP Control Center received a SCADA system alarm at 7:52 pm that indicated that the Ottawa Station lost electrical power and communications systems. The loss of power and communications systems occurred when the Ottawa Station was struck by lightning. When the power was restored, the local PLC placed the station in local control and restored valves and set points to the last known positions. At 7:53 pm the Control Center received another alarm that indicated that the pressure in the ES 20-inch line had exceeded the MAOP of the pipeline. The Control Center contacted the on-call operator for the Ottawa Station. An SSCGP employee arrived at Ottawa station at 8:09 pm. The Control Center attempted to alleviate the overpressure condition on the pipeline by making a valve mode change; however the attempt was unsuccessful because a PLC at the station had placed the station in the local control mode. At 8:15 pm, the on-call operator and another employee arrived at the Ottawa station and began lowering the pressure on the ES 20-inch line. At 8:16 pm, a Tonganoxie District employee received a phone call from a family member who reported a possible pipeline rupture just south of Lawrence, KS. Douglas County Emergency personnel arrived at the site at 8:25 pm and confirmed the rupture to the Douglas County, KS Dispatch Office. At 9:09 pm, the first SSCGP responder arrived at the rupture location. The section of the line that ruptured was isolated at 9:42 pm by the Baldwin mainline gate valve closure. SSCGP notified the NRC of the release at 9:56 pm on June 30, 2005 (NRC report number 764055). Page 3 of 5#

Page 4Failure Investigation Report – Southern Star Central Rupture Due to Overpressure Failure Date 6/30/2005 Summary of Return-to-Service SSCGP replaced the failed section of pipe with 60 feet of pre-tested pipe and reinforced four girth welds on either side of the replacement pipe. All initial repair work was completed by July 3, 2005 and the replaced pipeline was backfilled. The ES 20-inch line was pressurized in several increments (four 100 psig increments in most locations) and after each incremental pressure increase, a leak survey was conducted. Additional leak surveys were done at road crossings and near residential dwellings. No leaks were found and the line was returned to service on July 19, 2005. After the line was returned to service SSCGP made a decision to replace the lap welded pipe in the line and also replace all portions of the line that contained oxyacetylene girth welds. Approximately ten miles of pipe was replaced. The balance of the ES 20-inch line that was affected by the overpressure condition is modern line pipe which has been hydrostatically tested to a pressure of 720 psig. Investigation Details SSCGP sent the portion of the pipe that contained the rupture origin and several adjacent girthwelds to an independent metallurgical laboratory for analysis. The metallurgical investigation determined that the overpressure condition resulted in higher than usual membrane stresses in the pipeline and that “the failure occurred just outside of the area of the lap-weld seam, in steel that was free of process or fabrication related defects.” Fractures propagated in both the upstream and downstream directions to the girth welds at each end of the pipe joint. Both girth welds tore around the circumference of the pipe and the joint was ejected from the right-of-way. The joint of pipe was found approximately 150 feet away from the crater that was formed as a result of the rupture. The crater itself was approximately 20 feet in diameter. The SSCGP Control Center notified appropriate field personnel of an overpressure condition approximately three minutes after the overpressure alarm had been received in the Control Center. SSCGP field and office personnel immediately began to respond. SSCGP personnel were at Ottawa Station by 8:09 pm and at 8:16 pm, an SSCGP employee was advised of a potential pipeline rupture by members of his family and he in turn contacted the Control Center at 8:20 pm. Douglas County Emergency responders arrived at the rupture site at 8:25 pm and confirmed the incident location with the Douglas County, Kansas Dispatch Office. The Emergency Personnel also evacuated a residence that was located approximately ¼ mile from the site. SSCGP conducted an internal investigation in order to determine the root cause of this accident. Findings & Contributing Factors SSCGP determined that the root cause of the failure was operator error and the result of an employee not following procedures on April 26, 2005 when performing regulator maintenance. This error caused the monitor regulator, 1137 RM, to be left in an inoperable condition as the SSCGP employee left the valve in the pneumatic supply line to the regulator in the closed position (after performing a maintenance operation). The technician had qualifications revoked and was then re-qualified through the OQ process. The lap welded pipe in the line was replaced (approximately 10 miles of pipeline) as were numerous oxyacetylene girth welds. In order to prevent this type of failure in the future SSCGP added several control revisions including high select relays in an effort to provide pneumatic backup to the working regulators. Page 4 of 5#

Page 5Failure Investigation Report – Southern Star Central Rupture Due to Overpressure Failure Date 6/30/2005 SSCGP personnel implemented additional measures to protect the electrical systems from lightning strikes. This included improvements to the grounding systems, surge suppression, installation of shielded instrumentation cable, electrical isolation of transmitters from the pipeline, and relocation of a transmitter. Appendices Appendix A Maps and Photographs Appendix B NRC Report Number 764055 Appendix C Operator Incident Report Appendix D Metallurgical Laboratory Analysis Page 5 of 5#

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Page 18Appendix B - NRC Report Number 764055 *Report taken at 22:56 on 30-JUN-05 Incident Type: PIPELINE Incident Cause: EQUIPMENT FAILURE Affected Area: The incident occurred on 30-JUN-05 at 20:25 local time. Affected Medium: AIR ATMOSPHERE NATIONAL RESPONSE CENTER 1-800-424-8802 *** For Public Use *** Information released to a third party shall comply with any applicable federal and/or state Freedom of Information and Privacy Laws Incident Report # 764055 INCIDENT DESCRIPTION ____________________________________________________________________________ SUSPECTED RESPONSIBLE PARTY Organization: SOUTHERN STAR CENTRAL GAS PIPELINE OWENSBORO, KY 42301 Type of Organization: PRIVATE ENTERPRISE ____________________________________________________________________________ INCIDENT LOCATION COUNTY RD 460 County: DOUGLAS EAST 1400 RD State: KS ____________________________________________________________________________ RELEASED MATERIAL(S) CHRIS Code: ONG Official Material Name: NATURAL GAS Also Known As: Qty Released: 0 UNKNOWN AMOUNT ____________________________________________________________________________ DESCRIPTION OF INCIDENT THE CALLER IS REPORTING A NATURAL GAS RELEASE TO THE ATMOSPHERE FROM A RUPTURED 20 INCH PIPELINE. ____________________________________________________________________________ INCIDENT DETAILS Pipeline Type: TRANSMISSION DOT Regulated: YES Pipeline Above/Below Ground: BELOW Exposed or Under Water: NO Pipeline Covered: UNKNOWN ____________________________________________________________________________ DAMAGES Fire Involved: NO Fire Extinguished: UNKNOWN INJURIES: NO Hospitalized: Empl/Crew: Passenger: FATALITIES: NO Empl/Crew: Passenger: Occupant: EVACUATIONS: UNKN Who Evacuated: Radius/Area: Damages: NO Closure Type Air: N Length of Direction of Description of Closure Closure Closure Road: N Waterway: N Track: N Major Artery: N Page 1 of 2#

Page 19Passengers Transferred: UNKNOWN Appendix B - NRC Report Number 764055 Environmental Impact: UNKNOWN Media Interest: NONE Community Impact due to Material: NO ____________________________________________________________________________ REMEDIAL ACTIONS IN THE PROCESS OF ISOLATING THE LINE Release Secured: NO Release Rate: Estimated Release Duration: ____________________________________________________________________________ WEATHER Weather: CLEAR, ºF ____________________________________________________________________________ ADDITIONAL AGENCIES NOTIFIED Federal: State/Local: State/Local On Scene: POLICE AND THE FIRE DEPT. State Agency Number: ____________________________________________________________________________ NOTIFICATIONS BY NRC DOT CRISIS MANAGEMENT CENTER (PRIMARY) 30-JUN-05 23:00 U.S. EPA VII (PRIMARY) 30-JUN-05 23:03 NATIONAL INFRASTRUCTURE COORD CTR (PRIMARY) 30-JUN-05 23:00 NOAA 1ST CLASS BB RPTS FOR KS (PRIMARY) 30-JUN-05 23:00 RSPA OFFICE OF PIPELINE SAFETY (PRIMARY) 30-JUN-05 23:02 DEPT HEALTH AND ENV ATTN:MR HENNING (PRIMARY) 30-JUN-05 23:00 DOI/OEPC DENVER (PRIMARY) 30-JUN-05 23:00 ____________________________________________________________________________ ADDITIONAL INFORMATION NONE ___________________________________________________________________________ *** END INCIDENT REPORT # 764055 *** The National Response Center is strictly an initial report taking agency and does not participate in the investigation or incident response. The NRC receives initial reporting information only and notifies Federal and State On-Scene Coordinators for response. The NRC does not verify nor does it take follow-on incident information. Verification of data and incident response is the sole responsibility of Federal/State On-Scene Coordinators. Data contained within the FOIA Web Database is initial information only. All reports provided via this server are for informational purposes only. Data to be used in legal proceedings must be obtained via written correspondence from the NRC. Page 2 of 2#

Page 20Appendix C - Operator Incident Report NOTICE: This report is required by 49 CFR Part 191. Failure to report can result in a civil penalty not to exceed $25,000 for each violation Form Approved for each day that such violation persists except that the maximum civil penalty shall not exceed $500,000 as provided in 49 USC 1678. OMB No. 2137-0522 U.S. Department of Transportation Research and Special Programs Administration INCIDENT REPORT - GAS TRANSMISSION AND GATHERING SYSTEMS Report Date No. (DOT Use Only) INSTRUCTIONS Important: Please read the separate instructions for completing this form before you begin. They clarify the information requested and provide specific examples. If you do not have a copy of the instructions, you can obtain one from the Office Of Pipeline Safety Web Page at http://ops.dot.gov . PART A – GENERAL REPORT INFORMATION Nearest street or road City and County or Parrish a. b. c. State and Zip Code d. Mile Post/Valve Station e. Survey Station No. f. Latitude: Longitude: (if not available, see instructions for how to provide specific location) g. Class location description Onshore: Class 1 Class 2 Class 3 Class 4 Offshore: Class 1 (complete rest of this item) Area ___________________ Block # ___________ State / / or Outer Continental Shelf h. Incident on Federal Land other than Outer Continental Shelf Yes No i. Is pipeline Interstate Yes No 4. Type of leak or rupture Leak: Pinhole Connection Failure (complete sec. F5) Puncture, diameter (inches) Rupture: Circumferential – Separation Longitudinal – Tear/Crack, length (inches) Propagation Length, total, both sides (feet) N/A Other: Operator Name and Address Original Report Supplemental Report Final Report a. Operator's 5-digit Identification Number (when known) / / b. If Operator does not own the pipeline, enter Owner’s 5-digit Identification Number (when known) / / c. Name of Operator ______________________________ _______________________________________________________ d. Operator street address ________________________________________________________________________________________ e. Operator address _______________________ City, County or Parrish, State and Zip Code 2. Time and date of the incident / / / / / / / / hr. month day year 3. Location of incident 5. Consequences (check and complete all that apply) a. Fatality Total number of people: / / Employees: / / General Public: / / Non-employee Contractors: / / b. Injury requiring inpatient hospitalization Total number of people: / / Employees: / / General Public: / / Non-employee Contractors: / / c. Property damage/loss (estimated) Total $ Gas loss $ Operator damage $ Public/private property damage $ d. Release Occurred in a ‘High Consequence Area’ e. Gas ignited – No explosion f. Explosion g. Evacuation (general public only) / / people Reason for Evacuation: Emergency worker or public official ordered, precautionary Threat to the public Company policy 6. Elapsed time until area was made safe: / / hr. / / min. 7. Telephone Report / / / / / / / / NRC Report Number month day year 8. a. Estimated pressure at point and time of incident: PSIG b. Max. allowable operating pressure (MAOP): PSIG c. MAOP established by 49 CFR section: 192.619 (a)(1) 192. 619 (a)(2) 192. 619 (a)(3) 192.619 (a)(4) 192. 619 (c) d. Did an overpressurization occur relating to the incident? Yes No PART B – PREPARER AND AUTHORIZED SIGNATURE Area Code and Telephone Number (type or print) Preparer's Name and Title Preparer's E-mail Address Area Code and Facsimile Number Date Area Code and Telephone Number Authorized Signature (type or print) Name and Title Form RSPA F 7100.2 ( 01-2002 ) OPS Data Facsimile Page 1 of 3 Page 1 of 3#

Page 21Appendix C - Operator Incident Report PART C - ORIGIN OF THE INCIDENT 1. Incident occurred on Transmission System Gathering System Transmission Line of Distribution System 2. Failure occurred on Body of pipe Pipe Seam Joint Component Other: 3. Material involved (pipe, fitting, or other component) Steel Plastic (If plastic, complete all items that apply in a-c) Plastic failure was: a.ductile b.brittle c.joint failure Material other than plastic or steel: _________ 4. Part of system involved in incident Pipeline Regulator/Metering System Compressor Station Other: 5. Year the pipe or component which failed was installed: / / PART D – MATERIAL SPECIFICATION (if applicable) PART E – ENVIRONMENT 1. Nominal pipe size (NPS) / / in. 2. Wall thickness / / in. 3. Specification SMYS / / 4. Seam type 5. Valve type 6. Pipe or valve manufactured by in year / / 1. Area of incident In open ditch Under pavement Above ground Under ground Under water Inside/under building Other: 2. Depth of cover: inches PART F – APPARENT CAUSE Important: There are 25 numbered causes in this section. Check the box to the left of the primary cause of the incident. Check one circle in each of the supplemental items to the right of or below the cause you indicate. See the instructions for this form for guidance. F1 – CORROSION If either F1 (1) External Corrosion, or F1 (2) Internal Corrosion is checked, complete all subparts a – e. a. Pipe Coating b. Visual Examination c. Cause of Corrosion Bare Galvanic Stray Current 1. External Corrosion Localized Pitting Coated General Corrosion Improper Cathodic Protection Other: ____________________ 2. Internal Corrosion Microbiological Stress Corrosion Cracking Other: ____________________ d. Was corroded part of pipeline considered to be under cathodic protection prior to discovering incident? No Yes, Year Protection Started: / / e. Was pipe previously damaged in the area of corrosion? No Yes, How long prior to incident: / / years / / months F2 – NATURAL FORCES 3. Earth Movement => Earthquake Subsidence Landslide Other: 4. Lightning 5. Heavy Rains/Floods => Washouts Flotation Mudslide Scouring Other: 6. Temperature => Thermal stress Frost heave Frozen components Other: 7. High Winds F3 - EXCAVATION 8. Operator Excavation Damage (including their contractors) / Not Third Party 9. Third Party Excavation Damage (complete a-d) a. Excavator group General Public Government Excavator other than Operator/subcontractor b. Type: Road Work Pipeline Water Electric Sewer Phone/Cable Landowner Railroad Other: c. Did operator get prior notification of excavation activity? No Yes: Date received: / / mo. / / day / / yr. Notification received from: One Call System Excavator Contractor Landowner d. Was pipeline marked? No Yes (If Yes, check applicable items i – iv) i. Temporary markings: Flags Stakes Paint ii. Permanent markings: Yes No iii. Marks were (check one) Accurate Not Accurate iv. Were marks made within required time? Yes No F4 – OTHER OUTSIDE FORCE DAMAGE 10. Fire/Explosion as primary cause of failure => Fire/Explosion cause: Man made Natural 11. Car, truck or other vehicle not relating to excavation activity damaging pipe 12. Rupture of Previously Damaged Pipe 13. Vandalism Form RSPA F 7100.2 ( 01-2002 ) Page 2 of 3 Page 2 of 3#

Page 22Appendix C - Operator Incident Report F5 – MATERIAL AND WELDS Material 14. Body of Pipe => Dent Gouge Wrinkle Bend Arc Burn Other: 15. Component => Valve Fitting Vessel Extruded Outlet Other: 16. Joint => Gasket O-Ring Threads Other: Weld 17. Butt => Pipe Fabrication Other: 18. Fillet => Branch Hot Tap Fitting Repair Sleeve Other: 19. Pipe Seam => LF ERW DSAW Seamless Flash Weld HF ERW SAW Spiral Other: Complete a-g if you indicate any cause in part F5. a. Type of failure: Construction Defect => Poor Workmanship Procedure not followed Poor Construction Procedures Material Defect b. Was failure due to pipe damage sustained in transportation to the construction or fabrication site? Yes No c. Was part which leaked pressure tested before incident occurred? Yes, complete d-g No d. Date of test: / / mo. / / day / / yr. e. Test medium: Water Natural Gas Inert Gas Other: f. Time held at test pressure: / / hr. g. Estimated test pressure at point of incident: PSIG F6 – EQUIPMENT AND OPERATIONS 20. Malfunction of Control/Relief Equipment => Valve Instrumentation Pressure Regulator Other: 21. Threads Stripped, Broken Pipe Coupling => Nipples Valve Threads Mechanical Couplings Other: 22. Ruptured or Leaking Seal/Pump Packing 23. Incorrect Operation a. Type: Inadequate Procedures Inadequate Safety Practices Failure to Follow Procedures Other: b. Number of employees involved who failed post-incident drug test: / / Alcohol test: / / c. Were most senior employee(s) involved qualified? Yes No d. Hours on duty: / / F7 – OTHER 24. Miscellaneous, describe: 25. Unknown Investigation Complete Still Under Investigation (submit a supplemental report when investigation is complete) PART G – NARRATIVE DESCRIPTION OF FACTORS CONTRIBUTING TO THE EVENT (Attach additional sheets as necessary) Form RSPA F 7100.2 ( 01-2002 ) OPS Data Facsimile Page 3 of 3 Page 3 of 3#

Page 23Appendix D Metallurgical Report This document is on file at PHMSA#