A natural-gas pipeline running along Junipero Serra Boulevard in Stanford is on Pacific Gas & Electric Company's (PG&E) "Top 100" list of segments with greatest potential risk, according to a report released Monday by PG&E.
California Public Utilities Commission and Gov. Arnold Schwarzenegger had insisted PG&E release the "Top 100 Segments" report after a pipeline exploded on Sept. 9, creating an inferno in San Bruno that killed seven people, injured 50 others and destroyed 37 homes.
PG&E came under sharp criticism last week for not making the list public after it was disclosed that a portion of Line 132 near the explosion site had been identified as a high risk by PG&E in 2007.
No San Bruno portions of Line 132 were on the Top 100 list released Monday, however.
Company spokespersons originally said PG&E would not release the list due to security concerns. But under questioning by reporters on Monday, PG&E President Christopher Johns said fear of terrorism was not the issue; the list was in an Excel format that was unintelligible to anyone but engineers and required reformatting, he said.
The Peninsula has three main pipelines running its length: Line 132 and Line 109 follow Interstate 280 to Stanford and Palo Alto before turning eastward, and Line 101 aligns roughly with U.S. Highway 101, according to maps provided by the U.S. Pipeline and Hazardous Materials Safety Administration.
The Top 100 list identifies two segments of Line 109 -- a total of 6,005 feet along Junipero Serra north of Page Mill Road -- as requiring monitoring for corrosion. PG&E conducted an analysis of the cathodic system (a process that protects the pipeline segment from corrosion) and adjusted the cathodic system for better protection, according to the report.
A 2009 analysis showed "marked improvement," and engineers will continue monitoring the segment, the report stated. The short northern stretch along Junipero Serra is ranked 56 on the list, and longer contiguous southern stretches tied for 60, 61 and 62.
Line 132 as it runs through Palo Alto is not formally ranked on the Top 100 list. Only a 2,628-foot segment of the pipeline in San Jose is noted, at No. 26. But the report states that 31.9-mile stretch of Line 132, nearly the entire length from Milpitas to Crystal Springs Reservoir, including Palo Alto, is scheduled for retrofitting so that engineers can use high-tech scopes to internally inspect the 54-year-old pipeline for corrosion.
Line 132 is vulnerable to damage due to ground movement because of its proximity to the San Andreas Fault, PG&E's report stated. Based on inspections, PG&E will determine whether repair or replacement is warranted for various stretches. Construction is scheduled for 2012-2013.
In Palo Alto, Line 132 runs east along Page Mill Road and Oregon Expressway. The pipeline jogs south, zig-zagging along Alma Street, El Carmelo Avenue, Waverley Street, Loma Verde Avenue, Cowper Street, Ashton Avenue and Middlefield Road, according to a map by the Pipeline and Hazardous Materials Safety Administration.
One stretch of the gas line along El Carmelo was "retired," the map shows. In 1966, a gas explosion took place at El Carmelo School. A second, replacement line was installed along El Carmelo and currently is in use.
City of Palo Alto Manager James Keene said his staff is reviewing the Top 100 list. He received a call from PG&E on Sunday telling him there are no lines in Palo Alto on the list, only Stanford.
But the city is interested in obtaining more information, Keene said, calling the data and maps provided to the city by PG&E outdated and "incomplete."
City staff is drafting a formal request to PG&E to clarify where the PG&E gas lines run through the city and to define if there are high-risk locations in Palo Alto. Officials also want to know if there are other documents besides the Top 100 list released Monday that identify high-risk segments, he said.
Several reporters at a PG&E press conference Monday questioned the Top 100 list's credibility, since the San Bruno segment did not show up at all as a "red flag."
Johns said investigators' findings related to the explosion could help determine if present processes of evaluation for pipelines are good or not.
In response to an order by the California Public Utilities Commission, PG&E has nearly completed a resurvey of the three peninsula pipelines. The company still has to check a two-mile section located in an inaccessible area, Johns said. Workers found one small leak at a valve in Milpitas, he added.
The Top 100 list, created at the end of 2009, is an annual compilation of prioritized gas-line segments the company has identified out of 20,000. It is used as part of PG&E's risk-management program, Johns said, downplaying the list's frequent characterization as the top riskiest.
Paul Clanon, executive director of the California Public Utilities Commission (CPUC), agreed.
"I want to assure the public that the list is not of pipelines that are at risk or dangerous. The list is a tool used by PG&E to prioritize maintenance, repair, or monitoring of its gas pipelines," he said.
"The CPUC will review the list to ensure that PG&E is monitoring their system effectively. We will also ask the state's other regulated natural gas utilities to provide us with similar planning lists."
The pipelines were evaluated against four criteria: potential for third-party damage during construction work; corrosion, ground movement, physical design and characteristics of the pipe segment. PG&E also considers the proximity of the pipeline to high-density populations, reliability impacts and environmentally sensitive areas, he said.
Based on all of these factors, PG&E determines which segments warrant further evaluation, monitoring or other future action. The list is created to help inform future work plans. As conditions change from year to year, such as when construction is completed, PG&E re-evaluates the list, he said.
The commission Monday also released audits it conducted of PG&E's Peninsula Division in 2008 (a 2010 audit is being finalized) and the Hollister/Milpitas District in 2008, and PG&E's responses to the audit findings.
PG&E was cited for not complying with the minimum gas-safety requirements of Title 49, Code of Federal Regulations (CFR), Section 192, and for not maintaining adequate documentation and inspecting their gas facilities within the required time intervals, according to Terrie Prosper, the commission's director of news and public information office.
These violations were not considered hazardous to the public but were in violation of pipeline-safety regulations. The commission conducts audits of selected sections of each investor-owned utility's gas transmission and distribution system approximately every two years, Prosper said.
The commission also made available two letters sent by PG&E in response to the commission's executive director requesting a variety of information related to the San Bruno explosion. Those two letters, the 100-segments list, maps of the pipeline segments and the two CPUC audit reports are available at www.cpuc.ca.gov/PUC/events/sanbruno.htm.
Concerned residents can call PG&E at 1-888-743-7431 to find out if their home or business is located within 500 feet of a gas-transmission line or if it is on the Top 100 list.