Yesterday, NTSB Chairwoman Deborah Hersman visited the site of the San Bruno gas pipeline blast. Congresswoman Jackie Speier, introducing Hersman, called the area an “open wound.”

Hersman revealed yesterday that PG&E had waited until only recently to inform the NTSB that the pipeline that ruptured at a defective weld last year, causing a fire that killed nine people and destroyed 38 homes, had previously leaked at a similar weld in 1988.

KGO has put up raw video of the entire event. To skip Herman’s preliminary comments and go to questions from the media, fast forward to 9:40 of the video.

The first questions concern PG&E’s delay of sharing information about the previous leak. Hersman said the agency was still collecting information about how serious the leak was. She said this type of information had been requested at the beginning of the investigation, and that “we certainly would have expected to see that earlier in the process.”

Why the delay?

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“We do not know why PG&E did not provide this information to our investigators. I think that’s a question you’d have to ask PG&E.”

The Chronicle spoke to PG&E yesterday and reported this:

Brian Swanson, a PG&E spokesman, said the company found a document related to the 1988 leak last month in a field office. He said workers were conducting a leak survey just south of San Mateo that year and found a “small leak” of methane gas.

He said the leak was coming from a “pinhole” opening in a weld on a longitudinal pipe seam.

A 12-foot section of pipe was replaced and the repair was tested using high-pressure water, which can detect problem welds, Swanson said. However, the rest of the 51-mile line was not tested.

Swanson said the company gave the document to the federal safety board on May 20, “for them to assess whether it has any relevance in their investigation.”

Hersman said at the press conference that the delay in reporting the leak spoke to the issue of PG&E not being in a position to make good risk assessments due to the company’s lack of adequate information.

Congresswoman Jackie Speier answers questions at around 18:30 of the video.

Hersman also announced that the NTSB had issued three safety recommendations coming out of the investigation.

Deborah HersmanDeborah Hersman

Video: NTSB Chairwoman, in San Bruno, Addresses PG&E Delay in Reporting Previous Leak