According to an investigation performed by the San Francisco Chronicle, Pacific Gas and Electric ran illegally high gas pressure in transmission pipes that contributed to the San Bruno disaster of 2010.
Federal law requires that companies that lack information on the state of their pipes assume they are of the lowest grade, and use them at a lower pressure. However, as many as 30 pipelines in the state are missing records and were operated above those thresholds.
Between 2004 and 2009, two pipes just north of the blast site and one just south of the blast site carried illegal gas pressure. Had they been following legal guidelines, pressure would have been 20 percent lower.
According to the documents reviewed by The Chronicle, as many as 200 segments were operated illegally.
From the San Francisco Chronicle:
Pacific Gas and Electric Co. was operating at least three segments of the natural-gas pipeline that ran through San Bruno at illegally high pressures before the 2010 explosion that killed eight people, a Chronicle analysis of the company’s records shows.
When questioned soon after the disaster by federal investigators, the utility dismissed its own consultant’s findings that part of the line had been run at pressures higher than government rules allow. But annual reports that PG&E submitted to California regulators and the company’s pipeline data sheets show that three segments on the San Bruno line were being run at levels higher than the utility could justify, given that it was missing crucial records about the pipe.
Read the full article here.