In a statement issued Thursday, the San Francisco-based company "now expects that the U.S. attorney will charge that PG&E's past operating practices violated the federal Pipeline Safety Act in areas such as record keeping, pipeline integrity management and identification of pipeline threats."
The company added: "PG&E believes that criminal charges are not merited and that PG&E employees did not intentionally violate the federal Pipeline Safety Act."
Criminal charges would be the latest of several setbacks for the utility since the blast. Last year PG&E announced that it would pay $565 million in legal settlements and other claims stemming from the September 2010 natural gas explosion, which injured dozens and destroyed 38 homes.
The explosion of the 54-year-old pipeline underneath the San Francisco suburb was so powerful that it left behind a crater 167 feet long and 26 feet deep, with one 28-foot section of pipe flung 100 feet. It ignited a wind-driven fire that set treetops ablaze and illuminated the sky for miles around.
The agency issued a scathing report blaming PG&E for "baffling" mistakes, a "litany of failures" and lax oversight, saying it took the company nearly 95 minutes to shut off the gas spewing from the broken pipeline.
A report by the California Public Utilities Commission's Safety and Enforcement Division said its investigators found more than 100 violations by the company, some dating back decades.
Last May the regulators recommended that PG&E pay a record $2.25-billion penalty for the explosion, which would have been the largest ever levied by the agency. Before now the PUC's largest fine was $38 million, against PG&E for a 2008 natural gas explosion in Rancho Cordova.
No final decision has been made on a fine, which PG&E has argued would be excessive.
PG&E said it was "committed" to spend $2.7 billion of shareholder money for safety-related projects. It also said that it had completed nine of 12 safety recommendations made by the NTSB.
In a statement, PG&E Chairman and Chief Executive Tony Earley said the company was implementing changes to make its natural gas system the "safest and most reliable in America."
"San Bruno was a tragic accident that caused a great deal of pain for many people. We're accountable for that and make no excuses," he said. "Most of all, we are deeply sorry. We have worked hard to do the right thing for victims, their families and the community, and we will continue to do so."