AVISTA CORP

Incident Narrative

ON 11/19/2012 AT APPROXIMATELY 1331-HOURS (PACIFIC STANDARD TIME) ML ALBRIGHT & SONS CONSTRUCTION DUG INTO AND SEVERED A 4-INCH STEEL HIGH-PRESSURE NATURAL GAS PIPE WITHIN 5TH STREET, BETWEEN THE INTERSECTIONS OF BEACHEY AND DIKE BYPASS, IN LEWISTON, ID. THE MAINLINE, OWNED AND OPERATED BY AVISTA UTILITIES, WAS OPERATING AT 289 PSIG (300 PSIG - SYSTEM MAOP) AT THE TIME OF THE INCIDENT. THE EXCAVATOR DIG-IN RESULTED IN BLOWING GAS THAT IGNITED IN EXPLOSION, WHICH IS BELIEVED TO HAVE BEEN CAUSED BY AN EXCAVATOR BACKFIRE. THE RESULTING FIRE TOTALED THE EXCAVATOR EQUIPMENT INVOLVED IN THE INCIDENT AND CAUSED ADDITIONAL DAMAGE TO A RAILROAD CROSS-ARM, AN ADJACENT WAREHOUSE STRUCTURE AND LOCAL ELECTRIC DISTRIBUTION FACILITIES (ALSO OWNED AND OPERATED BY AVISTA UTILITIES). IT IS AVISTA'S UNDERSTANDING THAT THE CONTRACTOR WAS OPERATING USING LOCATES FROM A ONE-CALL TICKET THAT HAD EXPIRED 14-DAYS PRIOR TO THE INCIDENT AND MARKS WERE NO LONGER FULLY VISIBLE. AVISTA DISPATCH WAS NOTIFIED OF THE INCIDENT AT APPROXIMATELY 1335-HOURS. AVISTA PERSONNEL WERE EN-ROUTE BY 1338-HOURS AND ON LOCATION BY 1351-HOURS. GAS FLOW WAS ISOLATED AT 1355-HOURS BY CLOSING THREE SYSTEM EOP VALVES (AVISTA VALVE #S LEC 128, LEC 130 & LEC 542) WITHIN CLOSE VICINITY TO THE AREA. AT THIS TIME LOCAL FIRE DEPARTMENT RESPONDERS WERE ABLE TO CONTAIN THE FIRE. POLICE ALSO RESPONDED AND LOCAL MEDIA FOLLOWED THE INCIDENT CLOSELY. THERE WERE NO DEATHS AND ONLY MINOR INJURIES (NO HOSPITALIZATION REQUIRED) AS A RESULT OF THE EVENT. AVISTA GAS CONSTRUCTION CREWS WORKED TO REPAIR DAMAGED GAS FACILITIES OVER THE NEXT 9-DAYS FOLLOWING THE DIG-IN. THE SYSTEM WAS REPAIRED, RE-TESTED AND RESTORED TO FULL OPERATION BY 1530-HOURS ON 11/28/2012. ONLY ONE AVISTA NATURAL GAS CUSTOMER LOST SERVICE AS A RESULT OF THESE EVENTS. THE RESULTING OPERATOR AND NON-OPERATOR DAMAGE COSTS FROM THE EVENT ARE ESTIMATED TO EXCEED $50,000 WHICH IS THE REASON FOR THIS REPORTABLE. THE DETAILS RELATED TO THESE COSTS HAVE BEEN PROVIDED BASED UPON THE BEST AVAILABLE INFORMATION AT THIS TIME. WE PLAN TO REPORT SUPPLEMENTAL INFORMATION IF NECESSARY WHEN IT BECOMES AVAILABLE.