Pipeline danger: PG&E acknowledges it let corrosion vulnerabilities fester.

Utility acknowledges it ignored corrosion danger

Pacific Gas and Electric Co. is conducting emergency leak surveys on 180 segments of its natural-gas pipeline system after acknowledging it had ignored their vulnerability to corrosion, in some cases for years, the company said Tuesday.

PG&E’s policy is to develop a remedy plan within 60 days after discovering that a transmission pipeline is susceptible to corrosion, but some of the company’s major gas lines have been identified as potentially vulnerable since 2004, company officials say.

More than half the 180 pipe segments were found to have corrosion vulnerabilities this year, according to a list provided by the company’s head of regulatory compliance, Bill Gibson, in a letter to California Public Utilities Commission.

About a third of the segments are in the Bay Area, PG&E said.

The vulnerability is a lowered level of electric current running through the metal lines that is used to protect the pipes from soil contact. The electric current wards off external corrosion, which if unchecked can cause a pipeline to rupture.

Among the pipes with corrosion vulnerability is Line 132, the transmission line that ruptured at a flawed weld in San Bruno on Sept. 9, 2010, killing eight people and destroying 38 homes, PG&E said.

The company discovered this year that a 9-mile span north of the blast site and running up into San Francisco had inadequate protection against corrosion, but failed to meet its own 60-day deadline to address the risk.

Another section of Line 132, about a mile north of its southern terminus in Milpitas, was found in 2006 to be vulnerable to corrosion, but the company failed to act.

Gibson said PG&E would complete emergency leak inspections of all 180 problem areas by the end of this month.

The utilities commission issued a statement late Tuesday saying it is “analyzing the corrective actions PG&E has taken, including steps to prevent this from happening again, and will decide whether to issue a citation with a penalty for the violation.’’

David Eisenhauer, a spokesman for PG&E, said the company discovered the problems in January as it reviewed its pipeline integrity management program in the wake of the San Bruno disaster.

The company said it does not expect any corrosion it finds in the emergency surveys to be severe, but that it will promptly correct any problems it finds. It did not say whether it had already found corrosion at weak points in the system.

“Self-reporting issues with our pipelines underscores our intense focus on safety and our commitment to being open and transparent,” Nick Stavropoulos, executive vice president of gas operations, said in a statement.

“We cannot expect to solve all of our problems overnight,’’ said Stavropoulos, who joined PG&E after the San Bruno disaster. He added that the company is “proactively scouring every inch of our pipeline system looking for anything that may remotely pose a safety concern.”