In the years leading up to a deadly series of explosions and fires in Boston suburbs Sept. 13, Columbia Gas of Massachusetts had been trying to eliminate aging materials from its pipeline distribution system.
The NiSource Inc. subsidiary has steadily decreased the proportion of its system that is made of outdated materials, including cast iron and steel without certain corrosion resistant treatment, while also repairing more leaks on its gas mains and service lines, according to an S&P Global Market Intelligence analysis of federal pipeline data.
Iron and bare steel pipes are more leak-prone than more modern materials, so the U.S. Pipeline and Hazardous Materials Safety Administration and state pipeline safety regulators have pushed companies to upgrade their systems by eliminating aging infrastructure. The company had told communities in the area that it would be performing pipeline safety upgrades the day of the incident.
Columbia Gas of Massachusetts, known formally as Bay State Gas Co., has a pipeline modernization program in the works, as evidenced by the shifting proportions of materials on the company's system over time. As recently as 2013, about 20% of Columbia Gas of Massachusetts' gas mains and service lines were made of the more leak-prone materials. By 2017, that figure had fallen to about 13.75%.
Over 2013-2017 the number of leaks the company repaired annually has generally risen, while proportion of the leaks from corrosion have fallen in that time from 35.15% to 21.45%. Leak repairs related to causes classified as "other" — which can include vehicle damage and fires or explosions not originating with the gas system, among other causes — saw the greatest increase, reaching 47.18% of reported leak repairs for 2017.
According to the Massachusetts State Police, emergency responders dealt with 70 instances of explosions, fires and gas odor calls across dozens of blocks in Lawrence and North Andover, Mass., starting in the evening on Sept. 13. An 18-year-old resident of Lawrence died during the incident, and a local hospital treated about a dozen others for injuries.
The National Transportation Safety Board, an independent agency tasked with investigating safety incidents on pipelines and other transportation systems, will take the lead on the investigation and will work with other regulators. Columbia Gas of Massachusetts has shut off gas service to the area, and the utility has to visit each of the 8,600 impacted customers in the area to shut off gas meters and conduct safety inspections.
Multiple transmission pipelines crisscross the Columbia Gas of Massachusetts' Merrimack Valley service territory, including Tennessee Gas Pipeline Co., Portland Natural Gas Transmission System LP and Maritimes & Northeast Pipeline LLC.
Sens. Edward Markey, D-Mass., and Elizabeth Warren, D-Mass., on Sept. 14 called for a Congressional hearing on the incidents to understand how the disaster occurred and what can be done to ensure "these types of dangerous accidents do not happen again." Similarly, Democrats in the U.S. House of Representatives' Energy and Commerce Committee said they would be watching the events and investigation closely.
"As the committee with jurisdiction over natural gas and the pipeline system that transports it, we need to understand what happened, why it happened, and ensure it never happens again," Rep. Frank Pallone Jr., D-N.J., who serves as the ranking member, said in a Sept. 14 statement.
The Pipeline Safety Trust, an independent industry watchdog, declined to speculate on what might have caused the incident but expressed high confidence in the NTSB investigation process. Authorities identified over-pressurized lines as potentially at fault.
"We also hope that if the problem demonstrated so dramatically here is something that could occur in other areas of the country that the Pipeline and Hazardous Materials Safety Administration will soon release national guidance or safety orders to ensure the safety of us all," Carl Weimer, the trust's executive director, said in a Sept. 14 statement.