Oct. 12–LAWRENCE — The Merrimack Valley gas disaster was caused by Columbia Gas overlooking critical pressure sensors in its instructions to contracted workers replacing outdated pipeline in South Lawrence, investigators indicated Thursday.
Workers were removing outdated cast-iron gas lines from the intersection of Salem and South Union streets and replacing them with PVC pipes when the incident occurred, investigators said. Pressure sensors located inside the cast-iron pipe were not accounted for in a work order that Columbia Gas had provided to its contractors, according to a preliminary report from the National Transportation Safety Board. When the workers removed the cast-iron pipe, the sensors were removed as well.
As pressure in the newly abandoned cast-iron pipe fell, regulators within the system “responded by opening further,” allowing more gas into the pipeline and “increasing the pressure in the distribution system,” the report said. Without the pressure sensors to alert the system it had reached pressure capacity, the regulators “fully opened allowing the full flow of high-pressure gas to be released into the distribution system supplying the neighborhood, exceeding the maximum allowable pressure,” the report said.
In high pressure distribution systems, each individual customer has a regulator to reduce pressure before gas enters the dwelling; but a low-pressure system like the one affected instead relies on regulator stations throughout the system. Fourteen regulators operated on the affected line, bringing the pressure down from 75 pounds per square inch in the main pipeline to 0.5 psi as it was funneled in to buildings, according to the report.
Sens. Elizabeth Warren and Ed Markey sent a letter to Columbia Gas in September that said pressure in the affected distribution lines was as high as 6 psi — 12 times the safe limit — before the flow was cut off.
The instructions Columbia Gas provided to the contractors, earlier identified as Feeney Brothers employees, did not account for the critical sensors and did not “require their relocation,” investigators said. The work was performed “in accordance with steps laid out in the work package” Columbia Gas had provided.
The unprecedented disaster wreaked havoc across the communities of Lawrence, Andover and North Andover the evening of Sept. 13, damaging 131 structures, including at least five homes that were destroyed. A teenager was killed and at least 21 people were hospitalized, including two firefighters. An additional seven firefighters suffered minor injuries.
After reading the report Thursday, Lawrence police Chief Roy Vasque said he was amazed and somewhat relieved the gas disaster was not worse.
Vasque was one of the first to respond to 35 Chickering Road, where a 5-bedroom house exploded, killing Leonel Rondon, 18, and injuring four others, including Shakira Figueroa, 21, who suffered massive leg injuries and has undergone numerous surgeries. The Figueroa family has filed a lawsuit against Columbia Gas.
As bad as that scene was, Vasque said he now realizes “the whole neighborhood could have been wiped out.”
“So much of this could have been different and that’s the scary thing,” he said.
In a statement issued Thursday, Joe Hamrock, president and chief executive of Columbia Gas parent company NiSource, said his company has been “fully cooperating” with the NTSB investigation.
“As a party to the NTSB investigation, we are prohibited from discussing or speculating on the cause of the incident or facts related to it until the NTSB has completed its work,” Hamrock said. “However, we can say that, because safety is our top priority, in the hours immediately after the incident we suspended similar work and enhanced procedures related to our low pressure systems.”
Thursday afternoon, the Massachusetts Department of Public Utilities sent an advisory to all natural gas pipeline operators across the state, directing them to immediately review their own procedures. All “tie-in” work, like the project Columbia Gas was completing, should cease until the company has analyzed its protocol, according to the advisory.
The department is hiring an independent investigator to assess the safety of pipelines across the state, according to Brendan Moss, spokesman for Gov. Charlie Baker.
Minutes before the fires and explosions began, the Columbia Gas monitoring center in Columbus, Ohio — nearly 800 miles from Lawrence — received two high-pressure alarms at 4:04 and 4:05 p.m.; but that center “had no control” to close the valves, according to the report. Columbia Gas controllers reported the event to local employees in Lawrence at 4:06 p.m., the report said.
As the pressure climbed inside the pipelines, firefighter Pat Ruiz radioed Chief Brian Moriarty about a situation at South Union and Salem streets.
“They think a regulator somewhere blew up. … One of the guys almost got killed over here,” Ruiz says in the recorded audio, obtained by The Eagle-Tribune.
Moriarty warned crews that they were going “to have multiple calls.”
“Everyone stay calm,” he said, urging crews to rescue those trapped and shut the gas down at burning properties.
The first 911 call came in at 4:11 p.m., just five minutes after local Columbia Gas employees received a warning from Ohio. While the regulator at issue was shut off by 4:30 p.m., the “critical valves” of the distribution system were not closed until 7:24 p.m., more than three hours after the pressure first spiked, according to the report.
Officials in Andover and North Andover both pointed to the report as confirmation that the disaster was the result of human error, confirming speculation that had been floating around town for weeks.
“It confirms that there was human error involved, and I think it’s going to be incumbent on Columbia Gas and appropriate gas authorities to implement measure to prevent this from happening in the future,” said Andover Town Manager Andrew Flanagan.
North Andover Town Manager Andrew Maylor said that while the initial report “certainly specifies why the event took place,” it does not “answer every question about why.”
Lawrence Mayor Daniel Rivera said the report “did not present any conclusions but it does give us a clear and concise outline of the facts of Sept. 13.”
“This moves everyone from rumor and innuendo to a corroborated set of facts,” he added. “I hope that this report does not distract Columbia Gas or NiSource from focusing on the primary objective of getting people back into their homes with heat and hot water by the Nov. 19 goal date.”
Follow Kiera Blessing on Twitter @kierablessing, Jill Harmacinski @EagleTribJill and Lisa Kashinsky @lisakashinsky.
(c)2018 The Eagle-Tribune (North Andover, Mass.)
Visit The Eagle-Tribune (North Andover, Mass.) at www.eagletribune.com
Distributed by Tribune Content Agency, LLC.