The kind of dramatic scenes that played out in suburban Massachusetts last month following a series of explosions and fires may serve as a warning of what lies ahead for the U.S., where an increasing reliance on natural gas is running up against aging infrastructure.
While there’s no firm conclusion about what caused the series of deadly blasts on Sept. 14, a preliminary National Transportation Safety Board report on the incident released this week says it was linked to work being carried out to replace old pipes. And across the U.S. there’s an awful lot of old pipes: In all, the country has about 80,000 miles of unprotected bare steel and cast or wrought-iron natural gas pipes—enough to wrap around the Earth three times -- much of which dates back to the early 1900s.
Technological Improvements
While those lines represent just 3.6 percent of all the pipes that deliver gas to consumers nationally, they pose the highest risk and account for 41 percent of all fatalities, according to the Pipeline and Hazardous Materials Safety Administration. PHMSA, as the regulator is also called, has urged operators to accelerate plans to replace the oldest lines because decades of wear and degradation has made them more brittle and prone to leaks or ruptures from ground movement. Exposure to rain and freezing temperatures is also a problem (modern gas lines installed in towns and cities are made of plastic, which is corrosion-resistant and less brittle, or from protected steel that won’t rust as easily).To be sure, the natural gas industry has come a long way technologically since it began about 200 years, with improvements such as new materials and inspection tools, said Christina Sames, vice president of operations and engineering with the American Gas Association, a Washington-based industry group.
18,000 Miles
Despite the inherent dangers of routing natural gas around the country above and below ground, its use has grown in recent years. It accounted for 29 percent of the U.S. energy mix in 2017, and that share is set to expand thanks to the exploitation of the massive reserves in shale-rock formations around the country through hydraulic fracturing, or fracking.That shale-gas boom has slashed the cost of electricity and is set to turn the country into the world’s third-largest shipper of the heating and power-plant fuel within the next two years. It’s also precipitated a huge build-out of pipelines. Since 2000, the Federal Regulatory Commission has authorized almost 18,000 miles of interstate gas transmission pipelines totaling more than 159 billion cubic feet per day of transportation capacity.
Past Incidents
The government figures include both large pipelines that crisscross the countryside as well as smaller lines serving residences. But as data from PHMSA makes clear, it’s the older pipes made of cast-iron that are disproportionately deadly.Similar incidents can be found on a grim list on the agency’s website. In January, for example, four people were injured in a Brooklyn fire that followed damage to a cast-iron gas pipe that the regulator says appeared to be caused by “frost heave,” where the ground swells upward due to freezing conditions. There were five deaths in 2011 after an explosion and fire in Allentown, Pa., where a preliminary investigation found a crack in a cast-iron main installed in 1928.
Massachusetts Scrutiny
According the NTSB report, crews contracted by Columbia Gas were replacing a cast-iron distribution main with a plastic one. When the workers removed a section of pipe containing pressure sensors, the system mistakenly registered a drop in pressure, triggering a surge of gas into the pipes that exceed the maximum allowed. The ensuing havoc killed one man and damaged 131 structures.U.S. Senator Edward Markey, a Massachusetts Democrat, said Oct. 12 that NiSource didn’t do enough to prevent it or respond quickly enough and that he’ll looking at “what we can do to change the laws in our country” to make sure it doesn’t happen again. NiSource President Joe Hamrock said in a statement that while the company is limited in what is can say about the incident while the investigation is still underway, immediately after the incident the company suspended similar work and it enhanced procedures related to low-pressure systems.
Oversight is a focus of lawmakers in Massachusetts, who are preparing to launch inquiries into the Merrimack Valley blasts. Those probes are likely to start after the Nov. 19 target for when NiSource plans to finish replacing pipelines in the affected areas, state Senator Mike Barrett, a Democrat, said in an interview just before the NTSB report was released.
“We are supposed to ultimately oversee the regulatory agencies involved,” he said. “There have been preliminary reports that the state Department of Public Utilities has too few pipeline inspectors to discharge oversight responsibility on its own.”
Such concerns have arisen in the past decade as U.S. shale plays come online, according to Weimer at the Pipeline Safety Trust. The Barnett shale in Texas and the Marcellus shale in Pennsylvania—two massive, gas-rich areas that have been opened up by fracking—“were being brought online and developed much more quickly than the regulatory infrastructure developed to keep an eye on them,” he said.
