Faulty Work by Gas Company Caused Massachusetts Explosions, Officials Say

A faulty plan to replace aging gas pipes caused sudden explosions and fires in three towns north of Boston last month that killed one person and drove thousands from their homes, the National Transportation Safety Board said Thursday.

Before the accident, on the afternoon of Sept. 13, a crew contracted by Columbia Gas was working on upgrading the natural gas distribution system in outh Lawrence. The company had approved the plan to replace century-old, cast-iron pipes, which had sensors to monitor pressure.

But disconnecting the old system disabled the gauges, and the full flow of high-pressure gas into the system — without an accurate read of how high it was — caused the explosions in Lawrence, Andover and North Andover.

The agency’s report, which is preliminary as the investigation continues, places the blame squarely with the company.

“Columbia Gas developed and approved the work package executed on the day of the accident,” it read. “The work package did not account for the location of the sensing lines or require their relocation to ensure the regulators were sensing actual system pressure. The work was performed in accordance with steps laid out in the work package.”

In a statement about the report, Joe Hamrock, chief executive of Columbia Gas’ parent company, NiSource, said the utility was “taking the steps needed to re-earn the trust of our customers, communities and public officials.”

Sen. Edward J. Markey of Massachusetts said the report raised even more questions about how such a catastrophe could have occurred.

“We need to turn over every stone and shine a light on the workings of this company and the entire industry,” he said in a statement.

In addition to the one person killed — Leonel Rondon, 18 — more than 20 people were injured and 131 structures were damaged, most from fires ignited by gas-fueled appliances. Five buildings were destroyed.

A month later, some people remain displaced, and more than 7,500 gas meters are still shut off, leaving residents without heat, hot water or cooking gas. Columbia Gas says it plans to fully restore service by Nov. 19.

The report lays out the chronology of an afternoon that “looked like Armageddon” as the fires burned.

Minutes before the explosions, the Columbia Gas monitoring center in Columbus, Ohio, received two high-pressure alarms for the outh Lawrence gas pressure system. One was at 4:04 p.m.; the other came a minute later.

The monitoring center does not open or close valves on its own, but it can advise field technicians. At 4:06 p.m., it notified the group in Lawrence. Just five minutes later, a resident placed the first of many 911 calls.

By the evening, there had been at least 70 reports of explosions, fires and strong gas odors. The three areas are home to more than 100,000 people, and firefighters found themselves putting out one fire, only to find another breaking out nearby. Thousands lost power and traffic jammed the roads out of town.

The Massachusetts Department of Public Utilities is hiring an independent evaluator to examine the safety of natural gas distribution throughout the state. After the release of the report, it ordered Columbia Gas to stop work except for emergency repairs and compliance work until at least Dec. 1.

The department issued a similar order to National Grid this week, pending a review of its safety practices.