AVISTA CORP

Incident Narrative

ON WEDNESDAY 11/8/23, AT 1242 PACIFIC TIME, AVISTA BECAME AWARE OF PRESSURE ISSUES IN OUR SE WASHINGTON SERVICE AREA (PULLMAN GATE STATION). AT 1254 THE AVISTA GAS CONTROL ROOM (GCR) RECEIVED NOTIFICATION FROM WHITMAN COUNTY (WA) EMERGENCY DISPATCH THAT AN EXCAVATOR HAD HIT A GAS LINE AND GAS WAS BLOWING NEAR US HIGHWAY 195 MILEPOST 27 AND THAT THE HIGHWAY HAD BEEN SHUT DOWN. AT THE SAME TIME, THE AVISTA GCR RECEIVED NOTIFICATION FROM WILLIAMS PIPELINE GCR THAT THEY WERE EXPERIENCING GAS PRESSURE ISSUES WITH THEIR LEWISTON LATERAL GAS LINE AND HAD A TECH IN ROUTE TO INVESTIGATE. AVISTA PROVIDED WILLIAMS SOME OF THE DETAIL WE HAD JUST LEARNED FROM WHITMAN COUNTY DISPATCH. WITHIN A SHORT TIME, IT BECAME KNOWN THAT A FARMER HAD HIT WILLIAMS PIPELINE'S 12"" TRANSMISSION LINE AND AVISTA WOULD LIKELY LOSE ALL GAS CUSTOMERS IN THE REGION. AVISTA MANAGEMENT PROCEEDED TO ""STAND UP"" ITS EMERGENCY OPERATING PLAN (EOP) TO RESPOND TO THE INCIDENT. (WILLIAMS NRC CASE #1383793) WITHIN A MATTER OF HOURS, AVISTA HAD LOST GAS SERVICE TO ROUGHLY 36,000 CUSTOMERS IN THE WASHINGTON TOWNS/CITIES OF PULLMAN, PALOUSE, ALBION, UNIONTOWN, COLTON, CLARKSTON AND ASOTIN AND THE IDAHO TOWNS/CITIES OF MOSCOW, TROY, DEARY, BOVILL, GENESEE, AND LEWISTON. AVISTA IMMEDIATELY CONTACTED THE AMERICAN GAS ASSOCIATION (AGA) TO SEEK THEIR ASSISTANCE IN MOBILIZING MUTUAL AID RESOURCES FROM OTHER GAS PROVIDERS IN THE REGION. AT APPROXIMATELY 1800, AVISTA CONTACTED THE NATIONAL RESPONSE CENTER AND REPORTED THE INCIDENT (AVISTA NRC CASE #1383817) DUE TO EXCESSIVE COSTS THAT WOULD BE EXPENDED TO RESOLVE THE OUTAGE. OVER THE NEXT TWO DAYS, A MASSIVE EFFORT WAS UNDERTAKEN TO TURN OFF ALL THE AFFECTED GAS CUSTOMERS, PRIMARILY WITH AVISTA PERSONNEL RESOURCES. ONCE WILLIAMS HAD COMPLETED THEIR REPAIRS AND REPRESSURIZED THEIR PIPELINE, AVISTA PROCEEDED TO REPRESSURE ITS HIGH- PRESSURE PIPELINE NETWORK. PURGE PLANS WERE ESTABLISHED AND RELIGHT AREAS WERE FORMALIZED BY GAS ENGINEERING AND GAS OPERATIONS PERSONNEL. THANKS TO GREAT ASSISTANCE FROM AGA, AVISTA'S MUTUAL AID REQUEST WAS ANSWERED BY EIGHT GAS COMPANIES AND MUNICIPALITIES FROM AS FAR AWAY AS SOUTH DAKOTA AND CALIFORNIA. ALTHOUGH SOME RELIGHTS HAD BEGUN AS EARLY AS FRIDAY 11/10/23, THE MAJOR RELIGHT EFFORTS BEGAN THE MORNING OF SATURDAY 11/11/23 WITH ASSISTANCE FROM MUTUAL AID PERSONNEL AND SOME LOCAL HVAC CONTRACTOR RESOURCES. RELIGHTS CONTINUED OVER THE COURSE OF THE NEXT FOUR DAYS. BY THE END OF THE DAY ON TUESDAY 11/14/23, THE FIRST WAVE OF VISITING ALL CUSTOMERS HAD BEEN COMPLETED AND OVER 95% OF CUSTOMERS WERE BACK IN SERVICE. CUSTOMERS WHO WERE NOT PRESENT DURING THE FIRST VISIT RECEIVED A DOORHANGER AND WERE INSTRUCTED HOW TO CONTACT AVISTA TO GET THEIR GAS SERVICE REESTABLISHED AT THEIR CONVENIENCE.