North Massachusetts house explosions throw spotlight on ageing gas pipes across the USA
24 September 2018
A series of explosions and fires in towns north of Boston on the evening of September 13, which killed one, injured 25 and left hundreds homeless, has been blamed on the overpressurisation of a gas main belonging to Columbia Gas of Massachusetts. But the focus has now shifted to ageing gas pipes across the USA that are prone to leaking and have been responsible for a number of fatal incidents.
In 2011, the Pipeline and Hazardous Materials Safety Administration (PHMSA), an arm of the US National Transport Safety Board, responded to several deadly gas explosions around the country by supporting states’ attempts to raise rates to enable utilities to repair and replace high-risk infrastructure.
Massachusetts, which has one of the oldest pipeline systems in the US, introduced a state law in 2014 giving gas companies 20 years to replace old pipes.
Plastic and steel pipes can usually withstand overpressurisiation, while cast iron ones often cannot. As of 2017, 97% of the nation's gas distribution pipes were made of plastic or steel, and cast-iron pipelines have been completely replaced in 19 states, according to PHMSA.
Before the Boston-area blasts, gas pressure was found to have been about 12 times what the system could hold.
A report by the Berkshire Eagle into the situation in Berkshire County in western Massachusetts found that the county’s gas supplier, Berkshire Gas Co., had been replacing its old cast-iron and unprotected steel pipes since before the 2014 legislation was enacted but still had about 48.6 miles of pipeline left to go, dating from 1879 to 1981.
The company owns more than 760 miles of mains in Berkshire, Franklin and Hampshire counties.
The American Gas Association estimates replacement costs at around $1 million per mile.
Natural gas heats 52% of homes in Massachusetts, an increase from 38% in 1990, according to a 2017 report by the Northeast Gas Association. Additionally, more than 50% of the electricity in Massachusetts is generated by natural gas.
According to report by MetroWest Daily News, other Massachusetts utilities have been in the spotlight over their ageing gas supply networks. After an investigation into gas supply in the Cape Cod area, the state cited National Grid, the largest gas utility in Massachusetts, for 16 significant safety violations, resulting in a $50 million improvement project.
Meanwhile, the Dallas Morning News reported that one Texas utility, Atmos Energy Corp., has some of the nation's oldest pipes in the country. It said the company's largest division, Atmos Mid-Tex, has received five times as many state safety violations as Houston's CenterPoint, the other large gas distribution company in Texas.
Atmos Energy responded by saying the safety violations were only alleged and that any problems cited by state regulators were fixed. It also noted that the number of citations peaked in 2013 and has markedly declined since then, which the company says reflects its emphasis on safety.
The company told regulators last year that 500 miles of cast-iron pipes remain in its network and that it will it need at least three more years to remove them. In Houston, CenterPoint removed virtually all of its cast iron gas pipes more than two decades ago.
More than a third of Atmos Energy's pipes were installed before 1940, the company reported to federal regulators last year. Among the country's big operators, only one, in Philadelphia, had such a significant share of old pipes.