NiSource Inc. has satisfied half of the safety recommendations the National Transportation Safety Board issued in response to a series of deadly explosions and fires along a Massachusetts subsidiary's system.
The board, or NTSB, announced on Sept. 4 that NiSource has fulfilled the board's recommendation to review the utility's gas system records and ensure they are "traceable, reliable and correct." The company has also developed and implemented processes to reduce risk when it modifies gas mains, NTSB said. Those include procedures to monitor main pressure and deploy assets that will allow NiSource to shut down its system when it detects potential problems.
The federal investigative agency issued the recommendations in November 2018, two months after NiSource subsidiary Columbia Gas of Massachusetts released high-pressure gas into low-pressure distribution mains along a recently replaced portion of the system in the Merrimack Valley. The subsequent fires and explosions in Lawrence, Andover and North Andover, Mass., destroyed five homes and damaged 131 structures, killing one person and sending 22 people to the hospital.
The Sept. 13, 2018, Merrimack Valley disaster destroyed five homes and killed one person. |
"The implementation of these recommendations is a significant step in improving natural gas pipeline safety for these communities and across the nation," NTSB Chairman Robert Sumwalt said in a news release. When the NTSB issued its recommendations to NiSource, the board described them as "urgent" and said they were needed to address "imminent threat to life safety."
The NTSB closed out the two recommendations on July 22. NiSource has documented its progress fulfilling two remaining NTSB safety recommendations and recommended in a July 29 correspondence that the NTSB close those cases, too.
One of the two outstanding NTSB safety recommendations would have NiSource revise its constructability and engineering review processes to make sure construction documents are accurate, complete and correct and to require a professional engineer sign off on plans before work begins on projects. The second recommends that NiSource implement best practices known as "management of change" to identify threats that could result in system failure when the company replaces pipes or makes other changes.
NiSource said Sept. 4 that it continues to engage and have technical discussions with NTSB as the company works towards fulfilling the remaining safety recommendations.
"The NTSB also supports our path forward on each, and we are making good progress toward the closure of the remaining two open recommendations," NiSource spokesman Ken Stammen said in an email. "The steps we have taken that are responsive to the NTSB urgent safety recommendations are part of the broader set of safety enhancements we are implementing across the enterprise, based on lessons learned."
The investigation into the Merrimack Valley disaster is still open, and the agency could issue additional recommendations, NTSB spokesman Keith Holloway said in an email. The NTSB will hold a board meeting on Sept. 24 to determine the probable cause of the fires and blasts.
NiSource has moved swiftly to resolve issues related to the Merrimack Valley disaster. The company agreed to pay $80 million in May to the three communities rocked by the blasts and $143 million in July to settle all class-action lawsuits over the incident.
NiSource expects to spend $1.67 billion to $1.72 billion for pipeline replacement and restoration, third-party claims and other expenses tied to the disaster.

