Development in once-rural areas put populations closer to natural gas pipelines

By Kimberly Lankford
Friday, October 29, 2010; 8:57 AM

On Sept. 9, a 30-inch natural gas pipeline exploded in the suburban community of San Bruno, Calif., creating a 2,000-degree fireball that killed eight people, destroyed 37 homes and left more than 60 people injured. A gaping crater replaced homes at the center of the blast.

Could it happen here?

A pipeline rupture of approximately the same magnitude did occur not far from the Washington area a couple of years ago, but with less-dire consequences.

On Sept. 14, 2008, a 30-inch span of the Transco pipeline ruptured in Appomattox County, Va., creating a fireball that destroyed two homes and caused five injuries. Twenty-three families were evacuated.

The Appomattox explosion was larger than the explosion in San Bruno, but it occurred in a less-populated area, said Carl Weimer, executive director of the Pipeline Safety Trust, a watchdog organization based in Bellingham, Wash.

The Appomattox rupture was caused by corrosion of the 53-year-old pipeline, which had been inspected three months earlier by a "smart pig," a computerized scanning device that travels through a pipeline searching for dings, dents or corrosion, but had not yet been repaired. Transco's owner, the Williams Cos., paid the U.S. Transportation Department a $952,000 fine, replaced 2,500 feet of the pipeline, "smart pigged" all of its pipelines in Virginia, and performed pressurized water tests to validate the repairs.

Aging pipelines - and growing populations in the once-rural areas where pipelines were routed decades ago - have increased the risks associated with ruptures throughout the United States.

"The average transmission pipe is 50 years old," Weimer said. "If you put a steel pipe in the ground 50 years ago, you can have problems. It's not the same strength as steel today, and it doesn't have the anti-corrosive coating. But the more important factor is how the company has operated and maintained the pipes."

Some of the largest interstate pipelines in the United States run through the Washington area. The massive Transco pipeline, which consists of three and four parallel pipelines of 30 to 42 inches each, runs through Culpeper, Fauquier, Prince William, Fairfax, Montgomery and Howard counties on its way north from the Gulf of Mexico and shale resources in Alabama to supply natural gas up the East Coast to New York City.

One of the largest import facilities for liquefied natural gas in the United States is at Cove Point in Calvert County. Tankers travel up the Chesapeake Bay to deliver gas from abroad; from Cove Point it is distributed via transmission pipelines throughout the region.

Columbia Gas Transmission also runs major gas pipelines across the western edge of the metro area. Washington Gas taps into these resources with 200 miles of high-pressure transmission pipelines, which run through every county in the metro area and even beneath the Mall. The pipelines connect to a 26,000-mile web of smaller distribution pipelines, typically three-quarters of a foot to one foot in diameter, where the pressure is reduced so the fuel can enter homes and businesses.

Digging up trouble

The majority of pipeline incidents in the D.C. metro area, however, are not from the large transmission pipelines. In fact, there haven't been any incidents on the 20 miles of 24-inch transmission pipelines in the District (most of which date to the 1960s) "as far back as anyone can remember," said Betty Ann Kane, chairman of the D.C. Public Service Commission.

Every year, local emergency services teams respond to thousands of natural gas calls - by far the most common hazardous-materials emergencies in the area. Most incidents are caused by digging and excavation near the smaller distribution pipelines.

"We have almost daily events involving natural gas distribution lines being struck by construction equipment," said W. Trice Burgess Jr., the assistant fire marshal of Fairfax County Fire and Rescue.

Better mapping technology and a public service campaign to remind people to call the free 811 service to get utility lines marked on their property before they dig (A good idea, even if you're just planting a tree - go to for more information), have cut down on problems. But they still happen, usually when people excavate without calling 811 first or because the maps were not as precise as they should be, said Dennis Wood, a major in the Prince George's County Fire/Emergency Medical Services Department who ran the county's hazmat program for several years.

Breaks to larger lines do happen, though. On Sept. 28, the Prince George's hazmat team had to evacuate Prince George's Community College in Largo when an excavator hit a four-inch high-pressure transmission pipe.

"Something of a large scale like that generally happens maybe once or twice a year," Wood said.

Natural gas is lighter than air and can rise and dissipate if it isn't ignited. But newer plastic pipelines can cause static electricity and ignite, or sparks from an excavation can ignite the gas. The gas leak at Prince George's Community College did not ignite, and people were able to return to their buildings within a few hours after Washington Gas shut off the supply and repaired the leak.

Some leaks stem from problems with pipes or their components. When investigating a 2005 house explosion in District Heights, the Maryland Public Service Commission discovered a spike in leaks in Prince George's County in 2004 and 2005. The leaks appeared to be coming from deteriorating seals within mechanical couplings installed between the 1950s and 1970s. Those couplings connect sections of the distribution lines to the service lines that carry gas into homes. Washington Gas agreed to replace the couplings in about a 100-square-mile area of Prince George's County.

The utility completed the replacement program in Prince George's County . It is beginning a similar program in the District to replace about 500 couplings over the next seven years, starting in several areas of Northeast and Southeast.

"There are different life cycles for different kinds of pipes, and this replacement of the couplings from the 1950s is an example of that kind of program," Kane said. "It's very organized, and they know from their records exactly which couplings had that kind of connection to hold the two sections of the pipes together, and they are methodically going through that."

Suburbs encroach

Development of the Washington suburbs has added to the stakes, especially for the large interstate pipelines.

"They tried to keep most of the big pipelines in rural areas when they were built," Weimer said. "But the communities have sprawled out a lot over the past 50 years, and now they're in urban areas. That's a huge issue."

The Transco pipeline runs through Centreville, Chantilly and Reston, communities that have been transformed since the first span of pipes were laid in the 1950s.

Robert E. Simon, the founder of Reston, bought the land that would become that community in 1961. Dulles International Airport, which spurred growth and development nearby, didn't exist until 1962.

And the transcontinental pipelines continue to grow. Williams is applying to the Federal Energy Regulatory Commission to construct about 1.44 miles of new 42-inch pipeline and replace about 1.35 miles of pipeline in Prince William and Fairfax counties. (See for details and maps.)

"Our pipeline is at capacity right now," said Williams spokesman Christopher Stockton. "We're replacing an existing pipeline with a larger pipeline that will relieve bottlenecks."

If it gets approval, Williams plans to start construction in August and place the new lines in service by November 2012.

A close call in Chantilly in October 2005 shows how important a coordinated emergency plan can be to averting a possible disaster. A Williams excavator doing work nearby punctured a four-inch hole in the Transco pipeline, causing a high-pressure leak of natural gas.

"Williams pipeline personnel immediately contacted 911 and sent workers to the closest gate valves, which were about a mile away, to shut down the system and blow off and reduce the pressure in that damaged pipeline," said Burgess, of Fairfax Fire and Rescue. "Fire department resources arrived on the scene rapidly and evacuated numerous nearby homes and isolated the area.

"Luckily, the conditions that day did not have the natural gas finding an ignition source, so there was not an explosion."

The Fairfax hazmat response team has emergency plans from all of the transmission pipeline companies, including maps with the locations and sizes of the pipelines, Burgess said.

"We are also working with several of the pipeline companies and our Office of Emergency Management to access these plans electronically during an emergency event," he said.

Safety vs. security

Balancing safety and national security is a tricky issue for the pipeline operators.

"The federal government took down all pipeline maps after 9/11," Weimer said. "After an extensive review of security concerns, they put back up the National Pipeline Mapping System that allows the public to see the pipelines in their communities [at] because that analysis showed that it was safer to have local people aware of and watching out for these pipelines than to try to hide their locations, which is impossible since the transmission pipelines are all required to be marked with signs."

The Transco pipelines are buried at least 3 feet below ground and generally have a 15-to -25-foot easement on each side of the pipeline, where nearby residents can't plant trees or build permanent structures. There is 20 to 30 feet of separation between the pipes when there are multiple pipelines within an easement, Stockton said.

Pipeline operators do keep some information private for security reasons.

"We don't share capacities, throughputs and constraints of our pipelines - the type of information that might indicate where the most damage could be done," Stockton said. "We share that only with the Department of Homeland Security, who reviews our security efforts regularly and advises on what we should do to protect our facilities."

Weimer, however, would like to see pipeline operators make more information public.

"The big thing that's missing is any records about inspections," he said. "We know what the past incidents are. We know if there have been enforcement actions. But we don't know much about the history of the line, the pressure, and when it was inspected. That basic information would make a lot of people sleep easier at night."

Weimer and colleagues at the Pipeline Safety Trust have testified before House and Senate committees since the San Bruno explosion, saying they would like to see more pipeline operators run "smart pigs" to inspect their pipelines. Some companies run a smart pig primarily on pipelines in highly populated areas - ominously called "high-consequence pipelines" - although Williams uses it in rural and urban areas.

"It's a pretty amazing device," Weimer said. "It's the gold standard for companies to know the shape their pipelines are in."

Critics at the Pipeline Safety Trust would also like to see pipeline operators continue to replace manual shut-off valves with automatic and remote shut-offs, especially after the San Bruno incident. Gas poured from the San Bruno pipeline while a technician had to drive across town fighting rush-hour traffic to turn off the gas by hand.

They also want safety requirements to keep up with development. High-consequence transmission pipelines are subject to stricter inspection rules. But only 7 percent of the pipelines in the United States are in that category, even though development has meant that many more that were in rural areas are now much closer to neighborhoods.

Lankford is a special contributor.

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