The Chronicle reported on Jan. 9 that on Dec. 9, 2008, PG&E intentionally boosted gas pressure on the
The utility said the spike was "part of our operating practice," and that it runs its lines at their maximum once every five years. It did not elaborate on its reasons for doing so.
Experts interviewed by The Chronicle said the 2008 surge could have exacerbated any existing weaknesses on the
The next spike happened on Sept. 9, when a malfunction caused a surge to 386 pounds on the pipeline running from
The spike coincided with the rupture of the
"We have suspended the practice of increasing pressure on a transmission line to ensure (its) operational flexibility, pending the outcome" of the National Transportation Safety Board's investigation into the explosion, PG&E spokesman Brian Swanson said on Jan. 10.