The final day of National Transportation Safety Board (NTSB) hearings Thursday looking into the natural gas transmission pipeline rupture last September in San Bruno, CA, ended with more questions than answers, but with its chairman noting that the record accumulated over the three days in Washington, DC, should not only help pinpoint the cause of the tragedy but also help prevent the same thing from happening again.

Technology options for testing and inspecting operating gas pipelines were outlined, and the lack of testing for pre-1970 installed lines was raised as an issue that needs to be addressed. Similarly, the seeming lack of awareness of the pipeline infrastructure in local communities was discussed as another area where more action is needed.

NTSB Chairman Deborah Hersman, who headed all three hearings, pledged to get more answers, but she cautioned that was only half the federal agency's assignment. Preventing another tragedy in the future is the other goal.

Regarding the San Bruno pipeline (Line 132) segment that failed killing eight people and destroying a residential neighborhood, Pacific Gas and Electric Co. (PG&E) reiterated that it will continue to be more proactive in trying to educate local officials and residents about the location and operation of its gas transmission pipelines. It committed to notifying any resident or business owner within 2,000 feet of a transmission line about that pipeline's existence.

To the revelation the second day of the hearings that San Bruno fire officials were unaware of Line 132, PG&E confirmed that before the Sept. 9 incident it had regularly conducted annual meetings for San Bruno and the other cities in San Mateo County to make police, fire and other emergency first responders aware of the pipeline locations in their communities.

"At the annual training we show general maps of the pipelines, and before the meetings we send fire agencies electronic links to the package of information on the National Pipeline Mapping System, from which the local officials can download maps of the pipelines in their area," a PG&E spokesperson told NGI, noting that since San Bruno's incident the utility has committed to making it even easier for anyone to access the information on pipelines.

"In addition to sending letters to the customers within 2,000 feet of lines, we will send letters to all customers, work with local news media and community leaders throughout the system as well as provide information through electronic channels [websites] and more."

Government officials and the utility were taken aback Wednesday when San Bruno Fire Chief Dennis Haag revealed that he was unaware of the locations of the PG&E transmission pipelines in his city prior to the rupture. PG&E's spokesperson said that in the past the invitations to its community briefing sessions have been sent to each of the applicable departments, and they decide who to send to the utility workshops.

In regard to the technical preventive and maintenance work on the pipelines various industry experts stressed the need for pipeline operators like PG&E to have multiple inspection tools at their disposal. Two American Gas Association (AGA) experts offered perspectives on industry benchmarking, data sharing and various pipeline safety approaches.

At one point AGA's Christina Sames, vice president for operations and engineering, was challenged by San Bruno and NTSB representatives when she said that incidents like what happened in San Bruno -- as horrific as it was -- are still in her opinion only "anomalies," not trends, based on her analysis of NTSB statistics that only two out of hundreds of incidents in the past 20 years have resulted in the loss of lives.

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