SOUTHWEST GAS CORP

Incident Narrative

PL C1-PL2021-0007 ON FEBRUARY 28, 2021 AT 04:16 SOUTHWEST GAS CORPORATION (SWG) WAS NOTIFIED BY THE PHOENIX FIRE DEPARTMENT OF A RELEASE OF GAS AND FIRE AT THE 7TH STREET BRIDGE LOCATED SOUTH OF UNIVERSITY DRIVE IN PHOENIX. SWG CREWS RESPONDED TO FIND A NATURAL GAS FED FIRE ENGULFING THE BRIDGE. A 10-INCH STEEL PIPELINE (MAOP 275 PSIG) IS SUSPENDED UNDER THE BRIDGE THAT CROSSES THE SALT RIVER. SWG CONTROLLED THE FLOW OF GAS BY UTILIZING VALVES THAT RESULTED IN AN OUTAGE OF SIX COMMERCIAL ACCOUNTS (FIVE ACTIVE, ONE INACTIVE). THERE WERE NO INJURIES OR FATALITIES AS A RESULT OF THIS INCIDENT. NOTIFICATION WAS MADE TO PHMSA VIA THE NATIONAL RESPONSE CENTER (NRC) ON FEBRUARY 28, 2021 AT 6:42 AND WAS GIVEN NRC REPORT #1299214. AN UPDATE WAS PROVIDED TO THE NRC ON MARCH 1, 2021 AT 19:05 AND WAS GIVEN NRC REPORT #1299368. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD WAS NOTIFIED ON MARCH 1, 2021 AT 10:38 WHEN IT WAS DETERMINED THAT PROPERTY DAMAGE MAY EXCEED $1,000,000. NO REPORT NUMBER WAS GIVEN. INVESTIGATION INTO THE CAUSE IS STILL ONGOING, AND A SUPPLEMENTAL REPORT WILL BE SUBMITTED UPON COMPLETION OF THE INVESTIGATION BY SWG. SUPPLEMENTAL REPORT: THE REPORT WAS UPDATED TO REFLECT AN APPARENT CAUSE OF THE INCIDENT. PART G - APPARENT CAUSE WAS CHANGED FROM G8 ""OTHER INCIDENT CAUSE"" - UNKNOWN, TO G4 - OTHER OUTSIDE FORCE DAMAGE, INTENTIONAL DAMAGE, THEFT OF EQUIPMENT. THE INCIDENT INVESTIGATION IS STILL ONGOING, AND A SUPPLEMENTAL REPORT WILL BE SUBMITTED UPON COMPLETION OF THE INVESTIGATION BY SOUTHWEST GAS CORPORATION. SUPPLEMENTAL REPORT 2: THE REPORT WAS UPDATED TO REFLECT REVISED ESTIMATED COSTS. IN PART D #2, ESTIMATED COSTS WERE REVISED. 2.A. ESTIMATED COSTS OF PUBLIC AND NON-OPERATOR PRIVATE PROPERTY DAMAGE WAS REVISED TO $8,767,645, 2.B. ESTIMATED COST OF OPERATOR'S PROPERTY DAMAGE & REPAIRS WAS REVISED TO $2,098,109, AND 2.E. TOTAL ESTIMATED PROPERTY DAMAGE WAS REVISED TO $10,864,754. THE INCIDENT INVESTIGATION IS STILL ONGOING PENDING THE RELEASE OF THE FAILED COMPONENTS, AND A SUPPLEMENTAL REPORT WILL BE SUBMITTED UPON COMPLETION OF THE INVESTIGATION BY SOUTHWEST GAS CORPORATION. SUPPLEMENTAL REPORT 3: SOUTHWEST GAS CORPORATION'S INVESTIGATION DETERMINED THAT THE INCIDENT WAS CAUSED BY THE REMOVAL OF FASTENERS FROM A FLANGED JOINT BY AN UNKNOWN PERSON. THE REPORT WAS UPDATED TO REFLECT TYPE OF RELEASE INVOLVED. IN PART C #5, OTHER WAS CHANGED TO ""INTENTIONAL DAMAGE - REMOVAL OF FLANGE FASTENERS BY UNKNOWN PERSON"".