Columbia Gas of Massachusetts and its parent company, NiSource Inc., will pay $143 million to settle all class-action lawsuits stemming from damages related to gas explosions that rocked three cities and set off fires last year.
The deadly incident happened Sept. 13, 2018, during a project to upgrade century-old cast iron pipes with high density polyethylene pipes.
Because of a contractor error involving a sensor line, high-pressure natural gas was released into the low-pressure gas distribution system, causing widespread damage that killed one person and injured about two dozen in neighborhoods just north of Boston.
Five homes exploded and 125 structures were damaged in Lawrence, Andover and North Andover. Most of the damage was a result of structure fires ignited by gas-fueled appliances. A teenager was killed when a chimney collapsed on him.
The disaster left thousands of homes and businesses without gas heat or hot water, some for months. People used temporary housing while Columbia Gas replaced pipeline damaged by overpressurization.
The new system consists of high-pressure HDPE mains with regulators at each service meter to reduce the line pressure from the main when needed.
In all, NiSource has set aside about $1 billion to address the needs of customers and communities, including previous settlements with the family of the young man who died and a family that had several members injured. The $143 million settlement announced July 29 stems from a voluntary mediation process covering multiple class-action lawsuits and is subject to court approval.
The money will be placed in a settlement fund to help home and business owners who did not suffer physical harm but were displaced or significantly affected by fire and damage to boilers, furnaces, ranges and dryers. At its peak, more than 8,000 people in 2,200 families relocated to 4,000 hotel rooms, 160 apartments and about 200 RVs.
The National Transportation Safety Board continues to investigate the incident. Its preliminary report says a Columbia Gas contractor deactivated a cast iron main installed in the early 1900s without realizing the pressure sensors were still active. The system sensed pressure was falling and allowed the full flow of gas into the lines. There were no relief valves to relieve the overpressurization, and gas streamed into buildings.
"As a result, natural gas was delivered to customers at a pressure well above the maximum-allowable operating pressure, which led to the ignition of fires and explosions in homes," the report says.
NTSB also discovered that Columbia Gas omitted steps in its project workflow process that could have prevented "the error that led to the accident." The engineering plans used for the job didn't document the location of regulator-sensing lines in the natural gas distribution pipes that were slated to be abandoned.
As the system is updated with HDPE pipe, the Massachusetts Department of Public Utilities is providing oversight of the installation to ensure that all work complies with state and federal safety regulations.
Mark McDonald, president of NatGas Consulting in Boston, a firm that offers independent assessments and witness services for natural gas, propane and carbon monoxide incidents, said all parties need to recognize generally accepted good engineering practices.
"In my opinion the big lessons are to ensure gas companies do their due diligence on replacement programs, as well as have the correct professionals on-site when working in close proximity to critical infrastructure such as district regulator stations," McDonald said in an email.
A 2.1 million-mile system of distribution and service pipelines deliver huge volumes of natural gas to U.S. customers, and much of it is archaic in places like New York, Boston, Philadelphia and Washington, D.C. PE pipe is a popular replacement product because it is flexible and lightweight; resists corrosion, chemicals and abrasion; and is easy to install by using heat fusion or mechanical fittings.
If the Columbia Gas system had already been converted to HDPE pipe, overpressurization still probably would have occurred because it appears the failure points were at the end user's equipment designed for low-pressure gas, McDonald said.
However, the damage and outage time would have likely been limited, he added.
"If the infrastructure was plastic as opposed to cast iron, the outage would have likely been only days as opposed to months," McDonald said. "Cast iron is only designed for lower-pressure use. Plastic can be used for all distribution pressure."
The overpressurization of the cast iron pipe "compromised" miles of the system and it took more than three months to replace the damaged areas, McDonald said.
McDonald was retained by more than six law firms representing the deceased victim, injured victims and those that suffered property losses. He said he believes Columbia Gas has taken complete responsibility in terms of paying compensation at many levels.
"While we need to hold Columbia Gas responsible for this man-made disaster and act to learn from these mistakes, I do believe Columbia Gas responded more than appropriately in this case in terms of timely compensation for those affected to help heal the wounds created, in a very timely fashion," McDonald said.
The $1 billion set aside for settlements also includes $80 million to reimburse the three cities for curb-to-curb repairs of roadways and restoration work at homes and businesses needing 18,500 new appliances.
"What happened last September was tragic, and we will always be mindful of its impact on our customers and everyone in the communities we serve, including those represented by this settlement," Joe Hamrock, CEO and president of NiSource, said in a July 29 statement. "Today marks another important step forward, as we continue to fulfill our commitment to residents and businesses. We are pleased that we have reached a resolution so swiftly, and we thank the mediator, as well as all involved who helped us achieve this result."