After a Sept. 9 gas explosion in California killed eight people and destroyed nearly 50 homes, gas transmission lines here and around the country are getting new attention.
In some cases, that means ramped-up corporate inspections and repairs.
"The [U.S.] Department of Transportation and all of our [natural gas] companies had a heightened awareness and we started really looking at our operating processes," said Larry Buie, region manager of AGL resources, parent company of Chattanooga Gas Co. and Atlanta Gas Light Co.
"We want to make sure that we're not in a position to have a repeat incident."
About 10 miles of gas lines in downtown Chattanooga are undergoing testing and repair now, Buie said.
Similar work just ended on a section of a major, 12-inch natural gas transmission line owned by Spectra Energy, said Spectra spokeswoman Andrea Grover. The pipeline runs from Ooltewah to Signal Mountain, then to Marion and Sequatchie counties.
Grover said the company has regular and "rigorous" monitoring.
"We had three areas where we had water leaks," she said of the 21-mile section from Ooltewah to Signal Mountain. "When they find those, they dig them out to assess the problem. In most cases, we'll just replace the pipe there."
The Spectra gas line and the Chattanooga Gas lines downtown were originally laid in the 1940s and 1950s, though there has been some piecemeal repair and replacement through the years.
Both Grover and Buie said the line monitoring and repair is constant, and the testing is documented to the Department of Transportation.
"Age really isn't an issue," said Grover. "If you maintain the lines and have rigorous inspections, then they really don't deteriorate with age as humans do."
National questions
In a year when Americans also saw millions of gallons of crude oil pour into the Gulf of Mexico from a broken deep-sea well, tougher pipeline safety measures have gained public attention.
Legislation to toughen natural gas pipelines gained support on Capitol Hill last month. Sens. John D. Rockefeller IV, D-W.Va., chairman of the Senate Commerce Committee, and Frank Lautenberg, D-N.J., introduced their own pipeline safety bill. It followed one introduced by California Sens. Barbara Boxer and Dianne Feinstein, both Democrats.
Both require the installation of remote-controlled and automatic shut-off valves, a measure that proponents say would have limited the damage in the San Bruno, Calif., blast.
There, it took utility officials an hour and 46 minutes to manually shut off the pipeline.
The bills also would require more inspections and increase penalties for safety violations.
But Andy Black, president and chief executive of the Association of Oil Pipe Lines, also advised lawmakers in an Associate Press account to "think carefully" about overhauling regulations without knowing the causes of the recent pipeline ruptures.
Buie said "third-party damage" is the biggest challenge for natural gas pipeline operators in East Tennessee.
"Contractors, other utilities, municipalities, even sometimes homeowners -- even just installing fencing with deep post holes -- can cut into or damage gas lines," he said.
That's why gas companies have "call-before-you-dig" public education campaigns, he said.
If residents or contractors hit a line but think there's no damage, the gas company would still rather be called to check the gas line and maybe replace it, he said.
"In some cases if it's steel pipe, it may be years before the corrosion at the spot of damage will weaken the pipe enough to where it actually blows out," he said.