An internal memo recently handed over by PG&E to state regulators shows that the company had known about weld failures on the pipeline running underneath San Bruno for over twenty years before it exploded into a destructive fireball in 2010.
In 1988, PG&E discovered a leak in the pipeline only a few miles south of San Bruno and launched an investigation into what went wrong. The following year, the firm noted that the most likely reason for the fault was a defective weld along the pipe's seam--a similar issue to what cased the 2010 disaster.
The San Francisco-based energy giant only recently handed the memo over to regulators, claiming that it was unaware of its existence while government probes into the explosion were still open. The company discovered the memo during a search of eleven million documents related to its natural gas infrastructure.
According to federal law, the discovery of a problem with a seam weld should have triggered a test on the entire 51-mile pipeline that possibly could have discovered the flaw that left eight people dead and 38 homes in ruins. While that law was passed in 2002, it was retroactive and applies to the 1988 leak.
The pipeline, termed Line 132, wasn't originally constructed by PG&E. Instead, the company inherited it from the the now-defunct Consolidated Western, which had created the line in the 1940s and '50s, likely out of salvaged parts from old pipelines. The leak occurred near the Crystal Springs Reservoir, about nine miles south of the site of the San Bruno blast.
PG&E now counters that it was unlikely the 1988 leak was was due to a problem with a longitudinal seam weld. Instead, PG&E spokesperson David Eisenhauer told the San Francisco Chronicle that the culprit was actually girth weld, one that goes around the pipe instead of running along it, and would not have triggered a test of the full line because girth weld leaks are not considered as dangerous.
"Nothing about the 1988 leak or the [memo's analysis] suggested the need to test any portion [of the pipeline]," said Eisenhauer.
"This kind of information is stuff you just don’t lose or get buried," pipeline safety consultant Richard Kuprewicz of the The Utility Reform Network told CBS San Francisco. "I don’t care how many thousands or millions of documents you have."
Kuprewicz recommended regulators go back and take another look at how PG&E handles its record keeping. "There's a point where even the average person is going to ask, what the hell is going on down there in California?" he added.
In March, PG&E agreed to pay a $70 million settlement to those affected by the 2010 blast. The settlement comes in addition to a $100 million relief fund set up in the aftermath of the explosion as well nearly 100 individual lawsuits filed against the company.
The suits are scheduled to go to trail this July.
Here are some photos from the aftermath of the San Bruno pipeline blast:
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