SAN FRANCISCO -- Experts with the same regulatory agency disagreed Monday about whether a PG&E natural gas pipeline beneath San Carlos is safe to resume operations at full pressure, raising fresh questions about potential hazards linked to the pipe.

The formal disagreements between units at the Public Utilities Commission caused a state senator and one of the five members of the commission to express concerns about the differences of opinion within the powerful state regulatory agency -- more than three years after a fatal gas pipeline explosion in San Bruno.

Separately, San Francisco-based PG&E announced that it has successfully complied with two more recommendations from the National Transportation Safety Board about making PG&E's vast network of natural gas pipelines in California safer. The NTSB issued 12 recommendations in the wake of the San Bruno blast, a disaster that resulted in large part from PG&E's flawed records and inadequate maintenance.

The latest controversy springs from fears that PG&E Line 147 beneath San Carlos might not operate safely at the maximum allowable pressure of 330 pounds per square inch. A PG&E engineer initially raised questions about the line's pressure capability, and now a PUC engineer has produced fresh questions.


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"PG&E's data continues to be incomplete and erroneous," Tom Roberts, a senior engineer with the PUC's Office of Ratepayer Advocates, said in a report obtained by this newspaper. "PG&E's claim that Line 147 can be operated at the maximum allowable pressure of 330 cannot be substantiated based on the data PG&E has provided."

But another unit with the PUC, the regulatory agency's Safety and Enforcement Division, issued a report saying PG&E can safely resume operations at a line pressure of 330 p.s.i.

"This is outrageous that there are indications from a PUC engineer that Line 147 might not be safe," state Sen. Jerry Hill said in an interview with this newspaper. "The PUC is not on the same page with itself. There (needs) to be a thorough explanation about these different opinions."

Hill's comments were made following a legislative hearing he held Monday in San Francisco about whether the PUC is putting public safety at the top of its priorities when it comes to regulating PG&E and other utilities.

Once a PUC administrative law judge issues a recommendation about the San Carlos line, the full five-member commission will make a final decision on what pressure to allow on the 3.8-mile San Carlos pipe. PG&E currently is operating the San Carlos line at a minimal pressure.

"It is a concern to me that reasonable people are disagreeing about this," PUC Commissioner Michel Florio said.

The latest two items PG&E checked off from NTSB's 12 recommendations for improving pipeline safety involved upgrading risk assessment and threat assessment for the gas system. The three remaining items -- on which the NTSB says PG&E is making good progress -- are valve automation, hydro-testing of gas pipes and remote data access.

"This is a major milestone for the company regarding pipeline safety," PG&E spokeswoman Brittany Chord said of the NTSB announcement.

Contact George Avalos at 408-859-5167. Follow him at Twitter.com/georgeavalos.