State regulators in 2007 gave Pacific Gas and Electric Co. the go-ahead to spend $5 million of ratepayer money to replace a 62-year-old section of the same pipeline that exploded last week in San Bruno. But the work never got done as scheduled in 2009, and this year the utility asked for another $5 million to do the same job by 2013, according to documents submitted by PG&E to the California Public Utility Commission as part of a general rate-hike request.

While the cause of the pipeline explosion has yet to be determined, experts say that in general older lines are more prone to problems.

“There’s no excuse for deferring maintenance of potentially compromised pipelines that run under customers’ homes, businesses and schools,” said Mark Toney, executive director of the Utility Reform Network. The San Francisco ratepayer’s group, known as TURN, monitors electric and gas company regulatory activity.



“PG&E is responsible for maintaining the gas lines and has been given more than enough money to do so," said Toney, whose group released the rate-filing working papers on Wednesday.



In the 2011 request for capital expenditures, PG&E described the portion of the pipeline in South San Francisco, about 1.5 miles north of the segment that exploded, as ranking in “the top 100 highest risk line sections” in a 2007 evaluation.