Lattice of Underground Lines Means Scores of Leaks
By Marissa Barnett
For Reporting Texas
Leaking pipelines like the one that exploded near Milford in November draw the attention of news media, politicians and regulators, but hundreds of smaller leaks that don’t result in disaster go largely unnoticed.
The Milford liquefied natural gas pipeline blew up after an excavating crew pierced the Chevron Corp. line. No one was injured, but the entire town of around 700 was evacuated for two days. Milford is about 50 miles south of Dallas.
Hundreds of other gas leaks happen regularly, mostly for the same reason — people and machines digging into the buried lines. Construction contractors, utility companies, landscapers and homeowners all hit mainly residential gas lines while excavating.
The Texas Railroad Commission tracks reports of pipeline damages, including the small ones in neighborhoods. In Travis County, natural gas service companies filed 412 accident reports between Dec. 1, 2012 and Dec. 1, 2013.
Texas Gas Service Co., with the biggest service area in the county, generated 277 of the accident reports. Christy Penders, Texas Gas Service communications manager, said the company sends a crew to the site to assess the size of a leak.
“If a line is hit, it could be just a little nick or it could be that they cut the line and then there’s a larger leak,” she said. “Depending on the severity, we might need to shut off the gas to the area for a few hours while our crew works on the leak.”
For example, an October accident in South Austin shut down gas service for three days after Austin Water Utility excavators hit a natural gas pipeline. The estimated cost of repair was between $5,000 and $25,000, according to the Railroad Commission accident report. There was no estimate of how much gas leaked from the damaged pipe.
State law requires excavators to contact the statewide “811” center at least a day before they start digging. The center contacts pipeline companies, which mark the location of any lines under the digging site. Penalties for unauthorized digging are steep — up to $200,000 a day, up to a total of $2 million, according to the Railroad Commission.
The Legislature passed the Underground Facility Damage Prevention and Safety Act in 1997, which created a nonprofit corporation to run the statewide “one-call” system. The One Call Board of Texas, a 12-member board whose members are appointed by the governor, directs the corporation.
Two private companies, Dallas-based Texas Excavation Safety Systems Inc. and Maryland-based One Call Concepts, manage the 811 calls and serve as the liaison between callers and pipeline operators. Utility companies pay for the notification services.
“Everyone should call ‘811’ before digging and just say, ‘Hey, this is where I’m working, could you send someone out to mark the pipelines?’” Penders said. “It takes up to 48 hours to get someone out, but there’s no cost and calling can avoid accidents.”
Shakheana Fields, spokesperson for Texas Excavation Safety Systems, said the companies that manage the 811 system process 6,000 to 10,000 tickets per day.
“We get busy around March and stay busy through October — people doing construction, landscaping, putting in pools,” Fields said. “We slow down as it gets colder.”
When a call is received, the 811 operators take the contact information of the excavator and the location of the work.
“We need to know exactly where the work is being done — the address and where they’re digging on the property,” she said. “We get on a map, find the area and look at which utility lines are in the zone.”
The operator then files the ticket to the utility company with pipelines in the area and the utility company sends someone to locate and mark the lines on the property.
But not everyone puts in a call before digging. There were 216 accidents reports filed between Dec. 1, 2012 and Dec. 1, 2013 in which the person did not call 811 before digging.
The main fear associated with residential pipeline leaks is an explosion, which rarely happens. Virginia Palacios, a research at the Environmental Defense Fund’s Austin office, said the multitude of small leaks also creates environmental problems.
Methane — the stuff in natural gas that burns — is a powerful greenhouse gas that is thought to hasten global warming, she said.
“Controlling leaks that occur on distribution pipelines, transmission pipelines or anywhere, really, on the natural gas supply chain is really important to preventing climate change,” Palacios said.
Palacios pointed out that gas companies aren’t always precisely sure where their pipes are given the accuracy of older maps.
“They haven’t used GPS location, for example, on all their pipelines, so the accuracy within one foot might not be there on a map that somebody’s using,” she said.
Excavation isn’t the only cause of pipeline explosions. The last fatal explosion in Travis County happened in January 2012, when a corroded gas main blew up, killing a man in his nearby house.