Clark, a pipeline locator for South Carolina Electric and Gas, was following an electromagnetic signal transmitted from the utility company’s underground network of service lines and outlining the system’s path to let plumbers know where they could safely dig.
Area natural gas operators say that more people are having service lines marked before construction, landscaping and utility work but that still more caution is needed.
The dangers of natural gas leaks surfaced last month after a pipe explosion in New York City leveled two buildings and killed eight people in East Harlem.
An analysis by The Augusta Chronicle of annual reports from the federal Department of Transportation found that such leaks are common among the area’s two main operators, Atlanta Gas Light Co. and SCE&G, which together serve more than 1.8 million households.
In 2012, the latest year data were available, 1,973 natural gas leaks were reported by the two providers, and about half (48 percent) were considered hazardous because of the dangers they posed to people and property.
No major injuries were reported in Georgia or South Carolina from the leaks, but the two states have sustained nearly $11 million in damage since 2010.
On Sept. 28 of that year, a corroded gas pipe in the town of Cairo exploded, killing the Georgia public utility worker assigned to replace the city-run line and burning three of his crew members.
Only one natural gas-related injury has been reported since then in Georgia or South Carolina, and with April being National Safe Digging Month, industry professionals say they have upgraded aging and high-risk infrastructure, and are educating homeowners, contractors and public safety officials on pipeline safety laws to prevent future fatalities.
“It’s the nature of the beast,” said Deborah Flannagan, the executive director of the Georgia Public Service Commission, the board that regulates natural gas services. “All gas systems that have been in operation for many years will develop leaks as materials interact with nature.”
Flannagan said that in order to ignite, gas has to pool in a confined space until it makes up at least 5 percent of the air. Then, any flame or spark – even the flipping of a light switch – can set it off.
Not just Mother Nature is responsible for natural gas’s dangers. Records show that human hands are the greatest threat.
In 2012, excavation damage and loose equipment accounted for 66 percent of Atlanta Gas Light’s 1,408 leaks and nearly 80 percent of SCE&G’s 565 leaks.
In SCE&G’s Aiken area, which covers Aiken, North Augusta, Graniteville, Clearwater, Jackson, Blackville, Barnwell and Williston, 64 percent of the 57 leaks were caused by excavation damage and loose equipment, according to data provided to The Chronicle by SCE&G.
Atlanta Gas Light Co. would not break down its data by service district, but it said in a statement that more than 80 percent of annual leak repairs reported in the Augusta area were made after third-party damage and present no long-term risk to public safety.
Though industry professionals characterize equipment leaks as small and say they can usually be fixed by simply tightening loose fittings at meters, digging can cause mass damage and is typically classified as hazardous because of the heavy machinery and mechanized digging involved.
For example, a bank, a restaurant and a car dealership were evacuated in August 2010 after construction crews building sidewalks along Evans Town Center Boulevard broke a service line.
A month later, part of Walton Way Extension was closed and detoured several days after a construction contractor punctured a line while working on a project in front of First Baptist Church of Augusta – sending natural gas billowing into the air.
The latest natural gas leak in Augusta was an incident Monday on Millegedville Road involving a loose service-line fitting. It was cleared in less than an hour.
In 2012, more than half of Atlanta Gas Light’s 718 hazardous leaks and 76 percent of SCE&G’s 246 hazardous leaks were the result of excavation damage, which is why operators urge contractors and homeowners to call 811 and have underground utilities located and marked for free at least 48 hours before digging, as required by law in both states.
“This simple step taken a few days in advance of any excavation work helps keep the community safe and protect the integrity of our natural gas pipeline system,” said Kim Asbill, the public affairs specialist for SCANA, the parent company of SCE&G.
Thanks to communication efforts, Asbill said, SCE&G is seeing a noticeable improvement in excavation leaks.
Company records show that ratios of damage incidents to excavation projects have decreased from a rate of 6.3 in 2007 to 3.5 in 2013.
Knowing where to dig won’t eliminate all leaks, said officials from the federal Pipeline and Hazardous Material Safety Administration.
In 2011, after tragic natural gas incidents nationwide, the administration and its parent agency, the U.S. Department of Transportation, issued a “call to action” to accelerate the repair and replacement of the highest-risk pipeline infrastructure, specifically those constructed of cast and wrought iron, and bare steel.
A rupture in a major pipeline in San Bruno, Calif., in 2010, caused an explosion that killed eight people. A year later, an 83-year-old cast-iron main in Allentown, Pa., caused a blast that killed five people.
The federal government’s effort to eliminate lines vulnerable to cracks and corrosion has reduced the national mileage of distribution and transmission pipes constructed before 1970 by more than 8 percent, but about half of the country’s inventory remains more than four decades old.
“With proper maintenance, monitoring and replacement efforts, pipelines can continue to operate and last,” said Damon Hill, a spokesman for the Pipeline and Hazardous Material Safety Administration. “States have been favorable to helping with our effort – some are already ahead of the curve, others have started fresh – but we still have a long way to go.”
Asbill said that unlike other gas operators around the country currently replacing outdated facilities, SCE&G, which has nearly 360,000 natural gas customers, “proactively” completed replacement projects about 20 years ago for all cast-iron and bare steel pipe on its system.
Thirty-one percent of the 8,660 miles of pipe in its system either has an unknown construction date or was built before 1970, according to 2012 reports, which showed 35 leaks (nine hazardous) caused by corrosion.
The numbers are slightly better for Atlanta Gas Light, which serves 1.5 million natural gas customers in Georgia. Data from 2012 show 20 percent of its 31,280 miles of pipe either have an unknown install date or were constructed before 1970.
Further, the company, which reported 174 corrosion leaks (50 hazardous) in 2012, has no cast- or wrought-iron pipes in its system, but 65 miles of bare steel remains.
Kristie Swink Benson, the media relations manager for Atlanta Gas Light, said in a statement that all bare-steel and cast-iron mains in the Augusta area were removed more than three years ago as part of an accelerated pipeline replacement program the company started in 1998.
Atlanta Gas Light has invested more than $900 million over 15 years in its pipeline replacement program, replacing more than 2,700 miles of bare steel and cast iron in Georgia.
Additionally, last year it received approval from the Georgia Public Service Commission to proceed with the next phase of pipe modernization, making it possible for the company to replace the oldest vintage plastic pipelines installed between 1963 and 1984, Benson said.
“The natural gas industry, working together with regulators and manufacturers, (has) identified certain resins contained in vintage plastic pipe as being susceptible to early breakdown depending on service conditions, and this project addresses potential issues that may present themselves in the future,” she said. “Over the next four years the company will replace 756 miles of this vintage plastic pipe.”
In recent years, no safety-related issues have been found in SCE&G’s gas system, which Asbill attributes to a “rigorous inspection and testing schedule” that SCE&G follows year-round for all equipment and safety devices.
“We work every day to ensure the safety of the public we serve and to ensure the integrity of our pipeline system,” she said.