COLUMBIA GAS OF MASSACHUSETTS

Incident Narrative

ON SEPTEMBER 13, 2018, COLUMBIA GAS OF MASSACHUSETTS EXPERIENCED AN OVERPRESSURIZATION OF ITS LOW-PRESSURE GAS DISTRIBUTION SYSTEM IN LAWRENCE, ANDOVER, AND NORTH ANDOVER, MASSACHUSETTS. THIS INCIDENT WAS INVESTIGATED BY THE NATIONAL TRANSPORTATION SAFETY BOARD, WHICH ISSUED ITS REPORT ON SEPTEMBER 24, 2019. THAT REPORT, WHICH IS AVAILABLE TO THE PUBLIC, INCLUDES A NARRATIVE DESCRIPTION OF THE INCIDENT AND ITS PROBABLE CAUSE. PART A #5A -LOCATION IS ADDRESS OF THE FIRST PRIORITY CALL. MULTIPLE LOCATIONS ARE ASSOCIATED WITH THIS INCIDENT. PART A 12F - SOURCE OF INJURIES (25) WERE FROM PRESS RELEASES FROM MEDIA. PART A #13A - ALL VALVES WERE SHUT DOWN AT 19:24 ON 9/13/2018, BUT THERE WAS SOME BLEED THROUGH OF GAS UNTIL 6:26 ON 9/14/2018. PART A #16 - NUMBER OF CUSTOMERS EVACUATED IS UNKNOWN, DUE TO EVACUATIONS BEING COMPLETED BY MULTIPLE SOURCES INCLUDING BUT NOT LIMITED TO POLICE, FIRE, SELF/PUBLIC, OPERATOR, MAYOR OF LAWRENCE AND MEDIA. PART D #3B- INDUSTRIAL CUSTOMERS ARE INCLUDED IN OUR COMMERCIAL ACCOUNTS. PART E #1 - THE HIGHEST PRESSURE RECORDED WAS A 6.0, WHICH IS THE UPPER LIMIT OF THE RECORDING EQUIPMENT. 5.6.21- UPDATED PART A7 AND PART D. - COST OF GAS RELEASED, A13 -A15: TIMES ARE ESTIMATED AS THERE WERE MULTIPLE EMERGENCY RESPONDERS. A21C: VOLUME OF GAS LOST IN FIRE IS UNKNOWN, MULTIPLE FIRES. REQUIRED TO PUT IN A NUMBER. D6-7: BUILDINGS EVACUATED, AFFECTED IS BASED ON NUMBER OF CUSTOMERS AFFECTED. TOTAL EVACUATION NUMBER IS UNKNOWN. E3B: DEFAULTED DATE TO THE REGULATOR STATION INSTALL YEAR. THIS WAS A LOW PRESSURE SYSTEM WITH PIPE INSTALLED OVER MANY DECADES. THE SYSTEM WAS OPERATING AT PRESSURES CONSISTENT WITH 192.623.