NTSB recommends safety actions in San Bruno line blast probe

The National Transportation Safety Board issued seven safety recommendations, six of them classified as urgent, as a result of its investigation of the Sept. 9, 2010, natural gas pipeline rupture and explosion in San Bruno, Calif., which killed eight people.

Nick Snow
OGJ Washington Editor

WASHINGTON, DC, Jan. 6 -- The National Transportation Safety Board issued seven safety recommendations, six of them classified as urgent, as a result of its investigation of the Sept. 9, 2010, natural gas pipeline rupture and explosion in San Bruno, Calif., which killed eight people. It also scheduled a hearing for Mar. 1-2 as part of its inquiry.

“This accident has exposed issues that merit further attention and have implications for the pipeline infrastructure throughout the country,” said NTSB Chairwoman Deborah A.P. Hersman. “The hearing will gather additional factual information for the investigation and will also provide the pipeline industry, state, and federal regulators, and our citizens with an opportunity to hear more about this accident and important safety issues as the investigation progresses.”

NTSB noted in a Dec. 14, 2010, investigation update that while records of the gas distribution pipeline’s operator, Pacific Gas & Electric Co., showed the line in the rupture area was seamless, it at least partially was constructed of longitudinal steel pipe. Some of the seams in this pipeline section were welded from both the inside and the outside, while others were welded only from the outside, it added.

“It is critical to know all the characteristics of a pipeline in order to establish a valid [maximum allowable operating pressure (MAOP)] below which the pipeline can be safely operated,” the independent federal agency said in letters to PG&E, the California Public Utility Commission (CPUC), and the US Pipeline and Hazardous Materials Safety Administration. “NTSB is concerned that these inaccurate records may lead to incorrect MAOPs.”

Recommendations for PG&E
NTSB said it issued three safety recommendations, two of which were urgent, to PG&E as a result. It urgently recommended that the utility intensify the search of its records to identify all of its gas lines that have not undergone a testing regiment to validate a safe operating procedure. It urgently recommended that the utility determine the maximum operating pressure (MOP) based on the weakest section of pipeline or component identified in that records search. And if PG&E is unable to validate a safe operating procedure in this manner, it should determine one by a specified testing regimen.

Kirk Johnson, PG&E’s vice-president of gas engineering and operations, said the company was giving NTSB’s recommendations “close and serious attention.” He said PG&E has been intensively reviewing all of its pipeline records, scrutinizing and verifying thousands of documents to confirm the data’s accuracy. “We are managing this process across PG&E’s entire system as part of our ongoing commitment to place the highest priority on safety,” he indicated.

PG&E has been working closely with NTSB on its investigation as well as thoroughly reviewing its own records to confirm their accuracy, according to Johnson. “PG&E will continue to work closely with the NTSB, CPUC, and PHMSA to ensure we fully understand and are responsive to their recommendations,” he said.

The independent federal agency also expressed concern other gas pipeline operators may have similar discrepancies in their records that could compromise safety. It urgently recommended PHMSA expeditiously inform the pipeline industry of the San Bruno accident’s circumstances and investigative findings so pipeline operators can quickly implement corrective measures.

PHMSA advisory bulletin
PHMSA issued an advisory bulletin on Jan. 4, reminding operators of gas and liquid pipelines of their responsibilities under federal integrity management regulations to perform detailed threat and risk analyses that integrated accurate data and information from their entire pipeline system, especially when calculating MAOP and MOP, and to use these analysis methods to identify appropriate assessment methods and identify prevention and mitigation steps.

NTSB also directed three urgent recommendations to the CPUC, which regulates intrastate pipelines in California. It asked the CPUC to ensure that PG&E “aggressively and diligently” search documents and records to determine which pipeline segments have not gone through the testing regimen it recommended to the utility, and to provide oversight of any testing by PG&E if a documents and records search can’t be satisfactorily completed. CPUC also was asked to immediately notify other California intrastate gas pipeline operators of the San Bruno accident’s circumstances so they might implement corrective measures on their own systems.

Paul Clanon, CPUC’s executive director, immediately sent letters to Southern California Gas Co., San Diego Gas & Electric Co., and Southwest Gas Corp. as well as PG&E directing the companies to report steps they are taking in response to NTSB’s recommendations to him by Feb. 1.

In a Jan. 5 statement, the American Gas Association, which has primarily gas utilities as members, said it is encouraged by NTSB’s recent focused recommendations on operators’ need to have accurate records to ensure pipelines are operating at a proper pressure. “As this process continues, we look forward to learning more about the possible causes of this tragic incident, as well as additional recommendations for improving the gas utility industry’s already strong record of safety,” it said.

Contact Nick Snow at nicks@pennwell.com.

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