Almost 15,000 miles of natural gas and hazardous liquid pipelines run under Oregon’s landscape. With the release of the National Transportation Safety Board’s report on last year’s gas explosion in San Bruno, we all may be thinking about those miles of pipe a little differently.

The report, adopted unanimously by the board, lays the blame for the accident at the feet of the utility as well as state and federal regulators. The utility did not have adequate safety measures in place, and the regulatory bodies allowed the situation to continue.

It would be easy to let it end there. The explosion killed eight people, injured dozens more and decimated a neighborhood, but it happened a fair distance from Portland.

The board clearly stated, though, that the problems that led to the accident — the worst pipeline explosion in almost 10 years — may not be unique to San Bruno or California.

About 300,000 miles of pipeline snake through the country, but only half are covered by most federal safety regulations. As the NTSB chair said, “The aging pipelines, our oldest pipelines really are without a safety net.”

The blast itself was caused by substandard welds and other issues in the 55-year-old pipeline. The accident, however, was an “organizational accident,” according to the board.

Part of the problem was a lack of documentation or just plain inaccurate documentation about that stretch of pipeline. The utility, Pacific Gas & Electric, produced records that indicated the pipeline was seamless and of uniform thickness.

Investigators discovered, though, that the pipe was of variable thickness and actually had seam welds — seam welds that failed.

What difference does it make, seams or no seams, uniform or variable thickness? We’ll cover that in a future post.

Source: Post & Courier, “NTSB faults PG&E, regulators in gas explosion,” Joan Lowy and Matthew Brown, Aug. 31, 2011