The air down there 

Monitoring Montana’s natural gas infrastructure

More than 30 homes were incinerated in San Bruno, Calif., early this month when a natural gas leak caused a massive explosion in a residential neighborhood. The unforeseen disaster—which killed four and left dozens more injured—prompted state and federal officials to begin assessments of distribution pipelines nationwide, and newspaper headlines have since highlighted the big question facing energy companies and consumers: Just how safe is the nation’s aging natural gas infrastructure?

The short answer, at least for Montana, is safer than most. According to Eric Dahlgren, a utility engineering specialist with the Montana Public Service Commission (PSC), Montana’s natural gas distribution network doesn’t rely on the decades-old cast iron pipes that lie at the root of many problems across the country. We’re not in the same replacement regime as other states, Dahlgren says, because our system consists of more modern piping components like plastic or cathodically protected metal.

“I would say that Montana’s pretty fortunate,” he says. “You find [cast iron pipes] a lot back east, and that’s a problem for some of those areas. Montana tends to have a newer system overall.”

That’s not to say Montana doesn’t have its fair share of concerns when it comes to infrastructure. Public Service Commissioner Gail Gutsche says systems are in constant need of inspection, maintenance and even eventual replacement as age and the elements work against continued safety. The PSC’s biggest interest is preventing potential disasters, whether caused by natural gas or other hazardous substances.

“Obviously, there is aging infrastructure all over the nation,” Gutsche says. “And it should be pointed out that it’s not limited to natural gas transmission and distribution lines. Water lines are aging infrastructure; wires and poles with electricity are aging infrastructure. All this infrastructure needs maintenance and replacement at some point.”

For Montanans, the fireball that rocked San Bruno Sept. 9 resurrected memories of the tragic March 5, 2009, blast in downtown Bozeman that killed Tara Reistad Bowman, owner of the Montana Trails Gallery. That incident—the only fatal one on record in Montana between 2000 and 2009, according to the U.S. Department of Transportation (DOT)—also destroyed four buildings on E. Main Street and generated a flurry of litigation against utility provider NorthWestern Energy over allegations of negligence. The PSC found no direct links between the explosion and five probable violations discovered earlier that year.

“There were no probable violations by NorthWestern Energy that were deemed to have actually caused the incident,” Gutsche says.

The PSC later determined the source of the explosion to be a crack in a service line behind one of the destroyed buildings, likely a result of frost heave.

Montana boasts a fairly clean record when it comes to natural gas safety. The state’s 5,313 miles of natural gas distribution pipelines—roughly 63.5 percent of Montana’s entire commodity transportation infrastructure—have been the source of only five serious incidents recorded in the past decade. Comparatively, the DOT, which keeps statistics on the country’s 2.5 million miles of natural gas pipeline, lists 844 serious incidents nationwide since 1990. In the aftermath of the San Bruno explosion, U.S. Secretary of Transportation Ray LaHood even pushed legislation to increase federal oversight of natural gas infrastructure and raise fines for serious violations.

That’s not to say the PSC doesn’t have ongoing issues with natural gas pipelines. Of the five serious incidents since 2000, three resulted from damage from third party excavations. Individuals and businesses are required by law to alert NorthWestern Energy before breaking ground near pipelines. NorthWestern spokesperson Claudia Rapkoch says that doesn’t always happen.

“That is by far the single biggest threat to our system,” Rapkoch says. “The vast majority of problems we encounter every year are tied to third party dig-in, and to that point, we are working proactively with some of the other utilities in the state to see how we can strengthen some of those laws legislatively in the next session to minimize those third party damages.”

The severity of the issue came up again this May, when an electrical company in Columbia Falls ruptured a natural gas service line. The resulting explosion killed a NorthWestern Energy employee dispatched to repair the leak. Incidents like that are rare, says Blain Nicholls, operations manager for NorthWestern’s Missoula Division, but underscore the importance of public awareness.

“Third party damage, dig-ins, that type of thing—we try to minimize the impact of those,” Nicholls says. “But if somebody was to dig into our system and the public was aware of it, if they call in we can go out and safely make the repair and shut down the system.”

And while some segments of Missoula’s 1,050 miles of natural gas main and service pipelines date from as far back as the 1960s—portions that NorthWestern is gradually replacing—officials across the board say that’s no immediate cause for concern.

“Old doesn’t mean it’s unsafe or out of compliance,” Nicholls says. “Gas safety is the highest priority on our gas system. We operate to federal government regulations for operation and maintenance, so even though we may have some older segments in our system it doesn’t mean that they’re of any higher risk than anything else.”

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