AMEREN ILLINOIS COMPANY

Incident Narrative

REPORT UPDATED AND MARKED FINAL WITH FINAL COST ON 12/20/2019. SECOND PARTY CONTRACTOR FOR AMEREN ILLINOIS WAS EXCAVATING TO EXPOSE A 10"" GAS MAIN FOR MAINTENANCE. CONTRACTOR HAD CALLED JULIE (ILLINOIS ONE-CALL) FOR A LOCATE REQUEST. AMEREN ILLINOIS GAS DID NOT APPEAR ON THE LOCATE REQUEST, REPORTEDLY DUE TO A TICKET ENTRY ERROR BY THE ONE-CALL CENTER. THE CONTRACT LOCATOR WAS NOTIFIED TO LOCATE THE VICINITY FOR A DIFFERENT UTILITY, AND ATTEMPTED TO LOCATE THE GAS LINE SINCE THE CONTRACTOR ALSO LOCATES FOR AMEREN ILLINOIS. THE LOCATOR COULD NOT COMPLETELY MARK THE GAS FACILITIES DUE TO STANDING WATER ON THE GROUND, HE WAS ABLE TO MARK ONLY A PORTION OF THE MAIN AND NOT THE 3/4"" SERVICE THAT WAS ULTIMATELY DAMAGED. THE LOCATOR REPORTEDLY CONTACTED THE EXCAVATOR TO NOTIFY THAT HE COULD NOT COMPLETE THE LOCATE DUE TO WATER. THE EXCAVATOR PROCEEDED TO DIG TO EXCAVATE THE MAIN AND DAMAGED THE BURIED, UNMARKED 3/4"" STEEL HIGH PRESSURE GAS SERVICE, TEARING THE SERVICE IN TWO DOWNSTREAM OF THE SERVICE TEE OFF THE MAIN. AMEREN ILLINOIS ISOLATED THE DAMAGE BY INSTALLING TWO 10"" LINE STOPPERS AND RUNNING A BYPASS TO KEEP GAS SERVICE TO DOWNSTREAM COMMUNITIES. DUE TO VERY WET GROUND CONDITIONS AND DEPTH OF PIPE, THE EMERGENCY RESPONSE TOOK A LITTLE OVER TWO DAYS TO GET THE LINE SAFELY SHUT DOWN TO MAKE THE SERVICE REPAIRS. INITIAL ESTIMATES DURING THE RESPONSE INDICATED THAT THE GAS LOSS WOULD NOT EXCEED THE INCIDENT REPORTING THRESHOLD OF 3000 MCF. ONCE THE LINE WAS SHUT DOWN AND THE DAMAGE WAS ANALYZED, IT WAS DETERMINED THAT THE SIZE OF PUNCH (ORIFICE) IN THE SERVICE TEE WAS LARGER THAN ESTIMATED RESULTING IN A TOTAL LOSS OF 7040 MCF. IT WAS AT THIS TIME ON 5/18/2019 THAT IT WAS DETERMINED THE THRESHOLD FOR AN INCIDENT HAD BEEN MET AND THE NRC WAS NOTIFIED. THE LINE WAS SUBSEQUENTLY PLACED BACK INTO NORMAL SERVICE ON 5/18/2019 WITH ONE SERVICE INTERRUPTION TO THE EFFECTED CUSTOMER.