Merrimack Valley Gas Explosions Were Preventable: Official

ANDOVER, MA — The Merrimack Valley gas explosions that killed one and damaged or destroyed more than 130 buildings in Andover, North Andover and Lawrence last year could have been prevented, according to the National Transportation Safety Board official who led the agency's investigation into the disaster. At a hearing of the board Tuesday, Robert Hall, the NTSB's director of railroad, pipeline and hazardous materials investigations, followed up last year's preliminary report with testimony that firmly placed blame for the disaster on the utility, which is a unit of NiSource.

In addition to adopting new regulations to prevent similar disasters in the future and a recommendation that all work plans be reviewed by a licensed professional engineer, the NTSB's three-member board unanimously voted to adopt a resolution placing the likely cause of the gas explosions on Columbia's Gas's failure to have a mitigation plan in place.

"So do you think this accident could have been prevented had NiSource fully implemented a comprehensive [safety management systems] program?" NTSB board member Jennifer Homendy asked Hall.

"Yes I do," Hall said.

In a statement, Columbia Gas said its "own understanding of the events generally aligns" the testimony at Tuesday's hearing. The company has cooperated with NTSB investigators and since the explosions has installed automatic shutoff valves and implemented other safety protocols.

"We welcome today’s action by the NTSB because it will help us, our industry partners, the public, and others learn from this tragedy. As we’ve said since that tragic day, we take responsibility for what happened," Columbia Gas said.

After the explosions on Sept. 13, 2019, Hall said, Columbia Gas's slow response, coupled with problems with radio transmissions, led to more problems and unnecessary evacuations in the three communities. That strained resources and led to a recovery effort that lasted for months after the explosions, with thousands of people forced into temporary housing for months.

"Columbia Gas was not adequately prepared with the resources needed to assist emergency services to respond to a natural gas over-pressurization event," Hall said. "It's amazing to me that a company that operated this system for more than 100 yrs could not produce a map to firefighters and did not have information on valves as to how to shut the system down."

The preliminary report released last year found that Columbia Gas waited 26 minutes to shut down a gas regulator after an alarm sounded in its Columbus, OH, operations center. The report also concluded a crew working earlier in the day near the intersection of South Union and Salem Streets in Lawrence was replacing an older, low-pressure cast-iron gas pipe that had been installed in the early 1900s with a new plastic line. The regulators that should have sensed the increased pressure remained on the older, abandoned line. As the pressure dropped in that line, the regulators increased pressure to the new line.

On Tuesday, Hall elaborated on that report and said Columbia Gas did not have a licensed engineer reviewing the work plans for the project that set off the over-pressurization of the gas lines. He said such instances were "known risks" and Columbia Gas should have been aware f the potential hazards.

"They did not mitigate all the risks they had identified," Hall said.