A US energy company has ignored potential corrosion danger on a number of its gas pipes, research has reported.
Pacific Gas and Electric Company (PG&E),
a subsidiary of the PG&E Corporation, is conducting emergency leak surveys on segments of its natural-gas pipeline system after recognizing it had ignored their vulnerability to deterioration.
The firm, headquartered in San Francisco, provides natural gas and electricity across northern California.
It was reported by the San Francisco Chronicle that several pipes have burst during high pressure water tests, exposing structural weakness that weren't previously known about.
PG&E's own policy is to put into practice a remedy plan within 60 days of discovering a pipeline is susceptible to corrosion, but some gas lines had been defined as potentially vulnerable as far back as 2004 with no action taken.
In a cover letter to California Public Utilities Commission, Bill Gibson, the firm's head of compliance, explained more than half of 180 pipe segments were discovered to have corrosion vulnerabilities this year.
The issue is a lowered level of electric current running through the metal lines used to defend the pipes from contact with soil. The current shields against external corrosion, but can cause a pipeline to split if left unchecked.
Mr Gibson said emergency inspections of all problem areas would be complete by the end of the month.
Earlier this week, the utilities commission issued a statement saying it is analysing the action PG&E has taken, including steps to prevent this from happening again.
It will decide whether to levy a penalty for the violation, it said.
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.
Any corrosion found is not expected to be severe, but the firm said it would 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, was quoted as saying.
Corrosion protection is widely used in the energy industry, alongside other sectors including aerospace, business services and logistics.
It can be applied to metal, concrete and other materials, forming a barrier against corrosion, weathering and temperature.
