SOUTHWEST GAS CORP — Gas transmission and gathering — incident on 2014-11-13

Gas transmission and gathering incident in LAUGHLIN, CLARK COUNTY County, NV. Reported cause: EXCAVATION DAMAGE. Reported consequences: 0 fatalities, 0 injuries, 21963 NATURAL GAS released, $755 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20150067.

Operator ID: 18536.

Reported incident date: 11/13/2014 11:09.

Location detail: 2.86

Cause detail: EXCAVATION DAMAGE BY OPERATOR (FIRST PARTY)

Cause detail: EXCAVATION ISSUE

Cause detail: IMPROPER BACKFILLING PRACTICES

Cause detail: AN EMPLOYEE OF A PIPELINE CONTRACTOR (NPL CONSTRUCTION CO.) PERFORMING WORK ON BEHALF OF SOUTHWEST GAS UTILIZING A SOUTHWEST GAS PROVIDED FRONT-END LOADER, WAS PERFORMING MAINTENANCE TO REPAIR BERMS AND WATER BARS ALONG THE SOUTHWEST GAS TRANSMISSION LINE RIGHT-OF-WAY LOCATED IN LAUGHLIN, NEVADA AT MILE POST 2.86. THE SOUTHWEST GAS EMPLOYEE ONSITE AT THE TIME OF THE INCIDENT EXPLAINED THE SCOPE OF WORK TO THE EQUIPMENT OPERATOR (INCLUDING SPECIFYING THE CONSTRUCTION MEANS, METHODS, SEQUENCES, TECHNIQUES, AND PROCEDURES, AND COORDINATING ALL PORTIONS OF THE WORK). THE ROLE OF THE SOUTHWEST GAS EMPLOYEE WAS ALSO TO INSPECT THE WORK PERFORMED BY THE EQUIPMENT OPERATOR. THE BERM PROTECTING THE PIPELINE IS LOCATED BESIDE THE ROADWAY AND DIRECTLY ABOVE THE PIPELINE. PORTIONS OF THE BERM, WATER BARS AND ROADWAY HAD BEEN WASHED OUT BY PREVIOUS RAIN. THE INCIDENT HAPPENED WHILE THE EQUIPMENT OPERATOR WAS OPERATING THE FRONT-END LOADER AND RESULTED IN THE BUCKET DAMAGING THE PIPELINE. PART B, 11: THE FACILITY WAS UNDER SOIL, BUT THE DEPTH OF COVER IS UNKNOWN AS THE SOIL WAS DISPLACED BY THE ESCAPING GAS. PART C, 3.G: SOUTHWEST GAS DOES NOT TRACK THE PIPE MANUFACTURE DATE; THEREFORE, THE PIPE INSTALLATION DATE HAS BEEN LISTED. PART G3, EXCAVATION DAMAGE BY OPERATOR (FIRST PARTY): SOUTHWEST GAS HAS CLASSIFIED THE SUB-CAUSE AS FIRST PARTY EXCAVATION DAMAGE BECAUSE THE EMPLOYEE OF A PIPELINE CONTRACTOR THAT DAMAGED THE PIPELINE DID SO WHILE OPERATING A SOUTHWEST GAS PROVIDED FRONT-END LOADER AND WHILE WORKING UNDER THE DIRECTION OF A SOUTHWEST GAS EMPLOYEE WHO HAD SPECIFIED THE CONSTRUCTION MEANS, METHODS, SEQUENCES, TECHNIQUES, AND PROCEDURES. PART G3, 8: THE LAND USE RIGHTS IN THE SUBJECT AREA WERE OBTAINED FROM THE US BUREAU OF LAND MANAGEMENT BY RIGHT-OF-WAY GRANT. THE BLM TRANSFERRED ITS PROPERTY RIGHTS, SUBJECT TO SOUTHWEST GAS' RIGHT-OF-WAY GRANT, AND THE LAND IS NOW OWNED BY CLARK COUNTY, NEVADA. PART G3, 10: SOUTHWEST GAS CLASSIFIES THE TYPE OF EXCAVATION EQUIPMENT AS UNKNOWN/OTHER BECAUSE A FRONT-END LOADER WAS USED. PART G3 11: PLEASE SEE THE ABOVE NARRATIVE. PART G3 13-15: NEVADA LAW DOES NOT REQUIRE A ONE CALL TICKET UNDER THESE CIRCUMSTANCES. PART G3 17: SOUTHWEST GAS DESCRIBES THIS INCIDENT AS "EXCAVATION PRACTICES NOT SUFFICIENT (OTHER)" BECAUSE NONE OF THE OTHER SECOND LEVEL CAUSES USED IN THE DIRT REPORTING MATRIX APPLIES. SUPPLEMENTAL: PART C, 3.E: SUBSEQUENT LABORATORY INVESTIGATION DETERMINED THAT THE PIPE SEAM TYPE IS LONGITUDINAL ERW - LOW FREQUENCY.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: EXCAVATION DAMAGE — OPERATOR/CONTRACTOR EXCAVATION DAMAGE.

PHMSA indexed costs: $126,118 reported total cost, $83,510.661 in 1984 dollars, $115,229.205 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.