Unnatural disasters: What can be done about natural gas pipeline explosions?

A natural gas explosion in Springfield, Mass., injured more than 20 people and damaged 42 buildings.

The blast late last Friday blew out windows, scattered bricks for blocks, ripped through walls, and flattened some buildings altogether. Officials are still searching for the exact cause. But the debris-scattered, head-scratching aftermath of a natural gas explosion is not an unfamiliar scene.

An intentional gas leak is a prime suspect in a massive explosion that killed two and ruined homes in an Indianapolis neighborhood earlier this month. In October, a natural gas explosion destroyed a home in Castle Rock, Colo., and sent a family of five to the hospital.

These are dramatic examples of what the pipeline industry calls "significant pipeline incidents," which are usually lower-level accidents that nevertheless happen with alarming frequency. Every four days, the United States experiences three such incidents. 

What can be done to reduce the number of such incidents and the damage they inflict?

The damage is extensive. Since 1992, there have been 5,643 events that have resulted in fatalities, hospitalization, at least $50,000 in property damage, the excessive release of liquids, or unintentional fire or explosion, the Pipeline and Hazardous Materials Safety Administration reports. In total, the federal agency calculates, significant pipeline incidents have cost 373 human lives and more than $6 billion in property damage over the past 20 years.

Such problems appear to be increasing as the nation's network of 2.5 million miles of oil, gas, and other liquid pipelines grows. Although significant incidents are down from a peak of 361 in 2005, the 290 incidents that occurred last year represent an 8 percent increase over 2010. Significant incidents are up by nearly a quarter from a decade ago.

It's important to note that leaks do not always result in explosions or fatalities. And fuel transportation via pipeline is considered by many to be a much safer alternative to tanker trucks or freight trains.

"The natural gas industry has a proven record of safety," reads the Columbia Gas of Massachusetts website. "Each day, the underground invisible network of over a million miles of pipeline safely carries natural gas from supply areas to customers’ homes, businesses and factories across the country."

There are simple rules that individuals and businesses should follow. "Call before you dig" is the pipeline industry's reminder that the public should notify the proper authorities before undertaking any kind of excavation. While many pipes are marked with above-ground signage, locations are approximate and not all pipes are labeled.

If a gas leak is suspected, experts advise moving out of the area, notifying authorities, and refraining from using matches, appliances, cellphones, or anything else that may produce a spark.

These messages may be helping. In 2001, excavation damage caused a third of the significant incidents. By last year, its share was down to 14 percent. 

Worryingly, instances of "material weld equipment failure" are on the rise, rising from 8 percent in 2001 to 31 percent of significant incidents last year. The trends are captured in a recent data visualization and investigation produced by ProPublica, a nonprofit investigative news organization. ProPublica also found that only 7 percent of natural gas lines and 44 percent of all hazardous liquid lines are subject to PHMSA's rigorous inspection criteria and inspected regularly.

As the nation's vast, largely invisible energy infrastructure continues to age, some cities are threatened by the prospect of further incidents.

A November 2012 study by researchers at Boston University and Duke University found more than 3,000 leaks in the City of Boston's aging natural-gas pipeline system. Six of these leaks exceeded the threshold above which explosions can occur, the researchers found.

In response to the study, US Rep. Ed Markey (D) of Massachusetts called for infrastructure upgrades in a letter to the Pipeline and Hazardous Materials Safety Administration

“This study shows that we need a plan to ensure leaks from aging natural gas pipelines in Boston and other cities and communities are repaired, so that we can conserve this important natural resource, protect the consumers from paying for gas that they don't even use, and prevent emissions of greenhouse gases into the environment,” Representative Markey wrote in his letter of Nov. 21, just two days before the huge Springfield, Mass., blast. “We shouldn’t wait until a worst-case scenario occurs before we act to protect consumers, citizens and the environment.”