SAN FRANCISCO -- PG&E pleaded not guilty Monday to 12 criminal felony counts that allege the utility intentionally violated federal pipeline safety laws in connection with the 2010 natural gas explosion in San Bruno that killed 8 people, injured 66 and destroyed 38 homes.

The utility, whose executives weren't present for the arraignment, entered the not guilty plea through its attorneys at a hearing at the U.S. District Court in San Francisco.

Were PG&E to be convicted on all 12 felony counts, the utility could face a fine of up to $6 million. But the penalties could exceed $6 million if the court finds that the company gained financially from its misconduct or if the victims' losses are taken into account, according to the U.S. attorney's office, which is prosecuting the case.

"I'm confident that this criminal proceeding will show a clear path from the decisions that PG&E made to profits for the company and bonuses for its employees," state Sen. Jerry Hill, a Democrat whose San Mateo County district includes San Bruno, said in an interview with this newspaper. "It's troubling that knowing all of the facts, PG&E still maintains that it is not guilty."

San Francisco-based PG&E, in a news release issued after the arraignment, said, "While we don't believe any employee intentionally violated federal pipeline safety regulations, the legal process will ensure that all of the facts related to this tragic event are fully reviewed."

It characterized the San Bruno blast as "a tragic accident," and added: "We're accountable for that and make no excuses. Most of all, we are deeply sorry."

PG&E noted that it has committed $2.7 billion to upgrade and improve its century-old natural gas system. In an earlier filing, it warned securities regulators and its investors that it could be forced to accept court-supervised control by an outside authority of some or all of the utility's natural gas operations.

In a separate proceeding before the state Public Utilities Commission, PG&E faces fines of up to $2 billion as its punishment for the San Bruno explosion.

After a pair of administrative law judges at the PUC review the facts related to the potential fines and issue a proposed ruling, the five-member PUC will make a final decision, which is expected before the end of the year.

"We want to be certain that these proceedings ensure that the natural gas system is safe and that what happened in San Bruno won't happen somewhere else," San Bruno City Manager Connie Jackson said in an interview with this newspaper.

Jackson attended the arraignment and said she was disappointed that no PG&E executives showed up for the formal presentation of the charges.

Contact George Avalos at 408-859-5167. Follow at twitter.com/georgeavalos