News accounts over the years have chronicled many natural gas accidents, including what happened on Sept. 13 in the Merrimack Valley in Massachusetts. Thomas J. Tubman, executive director of the American Energy Coalition, delves into the details.
ON SEPT. 13 A SERIES OF NATURAL GAS EXPLOSIONS AND FIRES rocked the Massachusetts communities of Andover, Lawrence and North Andover, forcing residents to evacuate on that Thursday afternoon. One teenage boy was killed, at least 25 more were injured and natural gas was shutoff to about 8,600 gas meters. At one point during this catastrophe, in the town of Andover alone, there were some 38 structure fires and, in all, more than 131 structures were damaged or destroyed, news organizations reported.
The work underway by the local utility, Columbia Gas, a division of NiSource, was upgrading mains to improve safety. A 48-mile stretch of cast iron pipe was being replaced by a new plastic main. The work was being done by a sub-contractor in accordance with a detailed plan drawn up by Columbia Gas and with a Columbia Gas inspector on sight to ensure compliance with the scope of work, according to news reports.
Preliminary analysis by the National Transportation Safety Board suggests that the existence of a “sensing line” in the old cast iron pipe was overlooked, WGBH.org reported. That sensing line controlled a regulator that maintained the proper pressure in the old line. Since that sensing line was not relocated to the new plastic line, as the transition took place, and as the pressure dropped in the cast iron line being abandoned, it sent a signal to the regulator to increase the pressure in the new plastic line. It appears that eventually, the regulator opened fully and over-pressurized the entire system to 12 times the maximum allowable pressure, leading to the explosions and fires, WGBH.org reported, citing the NTSB.
The NTSB is conducting an investigation that is expected to take a year or more to complete. It is further reported that the state of Massachusetts has stepped in and removed the local utility, Columbia Gas, and ordered another utility, Eversource Gas, to manage the restoration of natural gas service. The original target date to fully restore service was Nov. 19; at this writing the date has been changed to mid-December. Many residences, then, remain without heat and hot water, and it is reported that many residents, anticipating colder weather, have not returned to their homes.
Under pressure shortly after the incident the utility announced that it would pay for conversions from natural gas to electric heat pumps or heating oil. The environmental lobby is focused on an “80 by 50” initiative (to reduce carbon emissions 80% from 1990 levels by 2050). Renewable electric and heating oil blended with biodiesel have a pathway to 80 by 50 and other environmental goals. Unfortunately, the oil heat industry lacks the capacity to take full advantage of this opportunity to convert natural-gas-fired homes to clean, renewable oil heat.
At the time of this writing, it is reported that less than a quarter of the systems damaged by the over-pressurization event have been repaired or replaced and had natural gas service restored. Restoration crews have been recruited from outside Massachusetts and the utility has even brought a cruise ship into nearby Boston harbor to house them.
Now, let’s look at the bigger picture: this catastrophe in the Merrimack Valley is not an isolated incident. There is a history of natural gas explosions and fires. In fact, this very same LDC (local distribution company) had a major incident in Springfield, Massachusetts, four years ago.
The incident happened on the Friday after Thanksgiving. A day care center directly across the street from the explosion site was closed. Had the explosion happened on a normal weekday, there would have been upwards of one hundred preschool children in the path of the blast. Firefighters and police were on sight with the utility crews responding to a complaint of the smell of gas. It was reported that after the neighborhood had been evacuated a worker punctured a pipe that caused the explosion. Here, according to news reports, is how the pipe got punctured:
Using what the utility calls a “bang bar,” the worker tried to open a shaft in the ground to allow a sensor to be dropped down looking for a gas leak. A bang bar is a heavy steel bar with a point at the bottom end. Another heavy-walled steel pipe is positioned over the steel bar; as the worker lifts and lowers the capped pipe, it drives the pointed bar into the ground. This provides the opening in the ground to drop the sensor down looking for the leak.
More recently, it has been reported that Columbia Gas has been fined by Massachusetts regulators in excess of $100,000 over the last eight years for various safety violations. And in a required SEC disclosure, Columbia’s parent, NiSource, said in late October that it was the subject of a federal criminal probe related to the Merrimack Valley accident.
Nationally, other incidents in recent years have killed and injured people and caused property damage.
According to USA Today, based on a review of federal records, there are 2.2 million miles of natural gas pipelines in the United States, with tens of thousands of those miles of pipes being outdated cast iron and bare steel pipe that was targeted for replacement decades ago. USA Today reports that 264 people have been killed in natural gas explosions since 1990, with an additional 1,600 or more injured, and at least $1.2 billion in property damage. Clearly, pipeline safety is a big problem.
USA Today further reported that in addition to deaths, injuries and property damage there are other costs and environmental damages associated with pipeline leaks. The newspaper reported that the Environmental Protection Agency estimated that in 2014, ratepayers paid $194 million for “lost and unaccounted for” gas that never made it to the ratepayer’s gas meters. EPA also pointed out the potency of methane gas (the primary ingredient of natural gas), citing it as a far bigger contributor to global warming than carbon dioxide. Maybe utilities and interstate pipeline operators should be required to replace their obsolete infrastructure by some date certain, repair leaks immediately, and stop the practice that allows them to recoup the cost of their “lost and unaccounted for” gas from their customers.
Posted on Tuesday, Nov. 20, 2018. A version of this column appears as an AEC Update in the December 2018 issue of Fuel Oil News.
Thomas J. Tubman is the executive director of the American Energy Coalition, which promotes the benefits of oil heat in comparison to other energy sources, particularly natural gas.