NORTHERN NATURAL GAS CO

Incident Narrative

ON NOVEMBER 27, 2018, MUMM BACKHOE AND EXCAVATING, LLC, WAS INSTALLING DRAIN TILE IN FARMLAND LOCATED NEAR COLO, IOWA. COMPANY OWNER GREG MUMM (""MUMM"") AND EMPLOYEE TIM ABEL (""ABEL"") WERE HIRED BY LAND OWNER DAVE EGGER (""EGGER"") TO INSTALL DRAIN TILE IN HIS FARM FIELD DUE TO DRAINAGE ISSUES ENCOUNTERED EARLIER IN THE YEAR. ABEL WAS OPERATING THE TILING MACHINE ON THE SOUTHEAST 1/4 SECTION, (S34, T48N, R21W) IN STORY COUNTY, IOWA, AND MUMM WAS ROUTING DRAIN TILE WITH HIS VEHICLE AND DRAIN TILE TRAILER. AT APPROXIMATELY 0945, ABEL WAS USING THE TILING MACHINE TO INSTALL DRAIN TILE IN THE NORTHWEST CORNER OF THE PROPERTY IN AN EASTERLY DIRECTION AND MADE CONTACT WITH AND DAMAGED NORTHERN NATURAL GAS (""NORTHERN"") 10-INCH-DIAMETER IAB66101 BRANCH LINE CAUSING A RUPTURE AND GAS LEAK. NORTHERN ISOLATED AND BLEW DOWN BRANCH LINE IAB66101 AND COMPLETED REPAIRS TO RESTORE SERVICE NOVEMBER 29, 2018. THE INCIDENT RESULTED IN A GAS RELEASE OF APPROXIMATELY 7.0 MCF AND AN EMERGENCY WHICH WAS REPORTED TO THE NATIONAL RESPONSE CENTER (NOTIFICATION #1231388 AND 1231571). THE ROOT CAUSE WAS FAILURE BY MUMM TO MAKE A ONE CALL NOTIFICATION PRIOR TO PERFORMING TRENCHING ACTIVITIES. HAD MUMM PROPERLY SUBMITTED A ONE CALL, THIS WOULD HAVE NOTIFIED NORTHERN TO PERFORM A LINE LOCATE, WHICH COULD HAVE PREVENTED THE LINE STRIKE.