NORTHERN NATURAL GAS CO — Integrity Assurance Notification

PROGRAMPlease accept this notice from Northern Natural Gas Company (Northern) as formal notification required per 49 CFR 192.909(b) and 192.18 that Northern has made a significant update to our Integrity Management Program. Due to the higher BTU content gas being received from Northern Border Pipeline Company, Northern has adopted the 0.73 rich natural gas coefficient for calculating the potential impact radius per 192.903. This method was applied resulting in an increase of HCA mileage from 165 miles to 180 miles.#