The filing comes as PG&E is seeking to settle dozens of civil suits filed against the utility in San Mateo County Superior Court without going to trial.
The rupture of the transmission pipeline in San Bruno killed eight people, injured dozens and destroyed dozens of homes on Sept. 9, 2010.
The San Mateo County Times reports ( http://bit.ly/SMbccF) that attorneys for the San Francisco-based company said in Friday's filing that PG&E only knew the flawed line "had been operated without any safety incidents for decades."
A trial date is set for January, 2013.
Information from: San Mateo County Times, http://www.sanmateotimes.com