SOUTHWEST GAS CORP

Incident Narrative

SOUTHWEST GAS EMERGENCY DISPATCH WAS NOTIFIED OF AN EXPLOSION AND POSSIBLE GAS LEAK IN THE AREA OF FIRST STREET AND COOLIDGE AVENUE BY A REPRESENTATIVE OF THE CITY OF LAS VEGAS FIRE DEPARTMENT AT 0640 ON THE MORNING OF JULY 11, 2010. MULTIPLE COMPANY EMERGENCY PERSONNEL RESPONDED TO THE SCENE AND DISCOVERED A GAS MAIN LEAK ON A TWO INCH PVC MAIN IN THE RIGHT OF WAY FOR THE PUBLIC STREET ON FIRST STREET BEHIND 921 SOUTH MAIN STREET. RESPONDING PERSONNEL HAD THE GAS MAIN LEAK UNDER CONTROL BY 0929. JANUARY 2012 SUPPLEMENT: BASED UPON THE RESULTS OF A THIRD PARTY ANALYSIS OF THE FAILED SEGMENT OF PIPE, THE CAUSE OF THE TWO-INCH PVC MAIN PIPE LEAK DISCOVERED ON FIRST STREET ON JULY 11, 2010 WAS A PREVIOUS THIRD PARTY'S FAILURE TO EMPLOY PROPER EXCAVATION PRACTICES. SPECIFICALLY, IT IS LIKELY THAT THE PIPE HAD BEEN UNCOVERED DURING A PREVIOUS EXCAVATION AND THAT THE BACKFILL WAS UNLAWFULLY AND INPROPERLY DUMPED BACK IN THE HOLE WITHOUT COMPACTION. THIS LEFT THE PIPE WITHOUT LATERAL SUPPORT FROM THE DOWNWARD LOADING CAUSED BY THE WEIGHT OF THE NON-COMPACTED BACKFILL, AND FROM OTHER POSSIBLE LOADINGS. THIS LED TO EXCESSIVE LONG-TERM DEFORMATION OF THE PIPE, CAUSING PREMATURE FAILURE.