SOUTHWEST GAS CORP

Incident Narrative

OPERATOR WAS NOTIFIED ON JUNE 14, 2018 AT 07:05 PDT BY LAS VEGAS VALLEY WATER DISTRICT, OF A LEAK ON FACILITY DUE TO AN ADJACENT LEAKING WATER LINE. A HAZARDOUS GRADE 1 LEAK WAS DISCOVERED ON A 4-INCH STEEL PIPE LOCATED AT 99 CONVENTION CENTER DRIVE IN LAS VEGAS, NV. THE FLOW OF GAS TO THE SECTION OF PIPE WAS TAKEN OUT OF SERVICE WHILE REPAIRS WERE COMPLETED WHICH RESULTED IN A SERVICE OUTAGE OF 16 COMMERCIAL CUSTOMERS. FROM THE START OF THE INCIDENT UNTIL ITS CONCLUSION, THE OPERATOR SHARED INFORMATION AND KEPT THE PUBLIC UTILITIES COMMISSION OF NEVADA (PUCN) INFORMED AS EVENTS WERE TAKING PLACE. AFTER THE INCIDENT, THE OPERATOR AND THE PUCN WERE IN COMMUNICATION CONCERNING THE ROOT CAUSE AND THE POST-INCIDENT SUMMARY. PART A, 4: BASED ON COMMUNICATIONS THAT THE PUBLIC UTILITIES COMMISSION OF NEVADA'S REGULATORY OPERATIONS STAFF HAD WITH THE PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION'S ACCIDENT INVESTIGATION DIVISION, ""LOCAL TIME AND DATE OF THE INCIDENT"" REFLECTS THE TIME OPERATOR PERSONNEL WAS NOTIFIED BY LAS VEGAS VALLEY WATER DISTRICT OF A POSSIBLE LEAK ON THE PIPELINE. AT THAT TIME, NO INCIDENT REPORTING CRITERIA HAD BEEN MET. PART A, 6: SOUTHWEST GAS NOTIFIED THE NATIONAL RESPONSE CENTER (NRC) TELEPHONICALLY OF THE INCIDENT ON JUNE 20, 2018 AT 12:35 PDT, DUE TO INCREASING COSTS ASSOCIATED WITH DEWATERING AND PURGING ACTIVITIES, THAT WOULD POSSIBLY MEET THE $50,000 REPORTABLE CRITERIA. THE NRC ISSUED REPORT NUMBER 1215896 FOR THE INCIDENT. SOUTHWEST GAS PROVIDED A 48-HOUR UPDATE TELEPHONICALLY TO THE NRC ON JUNE 22, 2018 AT 11:47 PDT AND ADVISED THAT THE INCIDENT DID NOT MEET $50,000 DAMAGE CRITERIA. AN EMAIL WAS ALSO SENT TO [email protected] ADVISING THE SAME. THE NRC ISSUED REPORT NUMBER 1216106 FOR THE FOLLOW UP REPORT. ON SEPTEMBER 13, 2018, OPERATOR DETERMINED THAT ESTIMATED COST OF EMERGENCY RESPONSE HAD INCREASED OVER 20 PERCENT, MEETING THE $50,000 REPORTABLE DAMAGE CRITERIA LARGELY DUE TO COMPANY PERSONNEL OVERTIME LABOR LOADINGS. BASED UPON THIS INFORMATION, THE PUCN WAS ADVISED OF THE UPDATED COST AND OPERATOR WAS DIRECTED TO SUBMIT THE WRITTEN REPORT BY OCTOBER 13, 2018. PART C, 5 AND G4: GAS PIPE WALL WAS ERODED-THROUGH BY WATER JETTING FROM AN ADJACENT LEAKING WATER PIPELINE. THE LEAKING STREAM OF PRESSURIZED WATER MIXED WITH SOIL AND SAND TO CREATE AN EROSIVE SLURRY THAT CONTINUALLY IMPINGED UPON THE STEEL GAS PIPE WALL RESULTING IN THE LEAK. SUPPLEMENTAL: PART A, 13A: CORRECTED LOCAL TIME & DATE OF SHUTDOWN FROM 10:19 TO 09:32.