Energy customers generally take for granted the pipelines that deliver natural gas to their homes and businesses. These pipelines are underground — out of sight, out of mind — and many are surprisingly old.
As The Bee reported on Saturday, Pacific Gas and Electric Co. operates more than 5,000 miles of natural gas pipelines in California. It is in the midst of a $2.2 billion program to replace about 2,000 miles of pipe. About 800 miles of pipeline is old cast iron and about 1,200 miles is steel pipe installed before 1930.
It is not yet known if age or inspection errors contributed to the pipeline explosion Thursday in San Bruno that killed at least four residents and damaged or destroyed 58 homes. Yet those factors are an obvious focus of a probe by the National Transportation Safety Board. Investigators are examining a 28-foot-long section of pipe that was thrown about 100 feet from the blast. According to the NTSB, that pipe segment was welded together in an unusual configuration.
The 28-foot pipe was part of a transmission line that stretched 51.5 miles from Milpitas to San Francisco. According to PG&E, this particular line (Line 132) is inspected annually for leaks, most recently in March, and was inspected for corrosion last November.
One serious concern is the half-hour that passed before crews could shut off gas flow to the broken line. That raises questions if PG&E has adequate shut-off valves along its lines to help bring a blast under control.
With public confidence shaken, the state Public Utilities Commission on Sunday announced it will order PG&E to inspect its entire intrastate natural-gas transmission system. California's two U.S. senators are also asking the Pipeline and Hazardous Materials Safety Administration to inspect 1,508 miles of interstate natural gas pipelines in California that are under federal jurisdiction.
That's a good start, but the PUC and members of Congress should go further – by inquiring if PG&E and other gas utilities made adequate attempts to carry out a federal inspections order that dates to 2004.
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