NORTHWESTERN ENERGY LLC

Incident Narrative

**** 6/10/11 **** FINAL REPORT - ON MAY 27 AND MAY 28, 2010 THE INVESTIGATION FOR THIS INCIDENT WAS CONCLUDED. THE INVESTIGATION DETERMINED THAT GAS MIGRATED FROM THE DAMAGED SERVICE LINE TO MAIN CONNECTION. THE GAS MIGRATED THROUGH THE SOIL ALONG THE SEWER LINE TO THE FOUNDATION OF THE HOUSE. INVESTIGATION OF THE SERVICE LINE TO MAIN CONNECTION VERIFIED THAT THE EXCAVATOR STRUCK THE SERVICE LINE AND TORE THE SERVICE LINE OFF THE SERVICE AT THE WELD. NWE CONSIDERS THIS INCIDENT CLOSED WITH NO FURTHER INVESTIGATION REQUIRED. ADDITIONALLY - ON THE FORM COULD NOT ACCESS SECTION G3 - 13A. FOR THIS SECTION THE SERVICE LINE WAS REMOVED FROM SERVICE AND WILL NOT REINSTATED. **** 06/29/10 WORKED WITH DOT TO GET THE REPORT CORRECTED FROM 06/04/10. AFTER SOME CORRECTIONS THE FORM IS WORKING AND THIS SUPPLEMENTAL IS TO SHOW THOSE CORRECTIONS. THE SERVICE LINE THAT WAS DAMAGED WAS REMOVED FROM SERVICE, WHICH IS SHOWN IN PART A UNDER 13B AS ""STILL SHUT DOWN"". THERE IS NO NEW ADDITIONAL INFORMATION TO INCLUDE IN THIS REPORT, THIS IS ONLY A CORRECTED SUPPLEMENTAL UPDATE. **** ELECTRIC UTILITY EXCAVATING FOR A STREET LIGHT MOVE STRUCK UNMARKED STEEL SERVICE, WHICH SEPERATED FROM SERVICE TEE UPSTREAM AT MAIN. GAS MIGRATED AND ACCUMULATED IN ADJACENT RESIDENCE AND EXPLODED. NORTHWESTERN ENERGY'S ADDRESS AND CONTANCT INFORMATION IN THE FRON PART OF THIS REPORT IS NOT CORRECT. THIS HAS BEEN BROUGHT TO THE ATTENTION OF MTPSC STAFF JOEL TIERNEY AND PHMSA WESTEN REGION ACCIDENT COORDINATOR PETE KATCHMAR. THE CORRECT CORPORATE ADDRESS SHOULD BE 3010 W. 69TH STREET, SIOUX FALLS, SD 57108. *** TRIED TO SUBMIT ON 06/04/2010 AT 17:42 COULD NOT SUBMITT CORRECTLY BECAUSE OF ERROR RECIEVED IN PART G - SPECIFICALLY G3 REQUIRES 13.A IF ""YES"" IS SELECTED IN 13. YES IS THE CORRECT ANSWER, HOWEVER I DID NOT GET A DROP DOWN FOR 13 A. THEREFORE, I SELECTED ""NO"" AND INDICATED AS SUCH HERE. ****