Pacific Gas & Electric is accused of lying to federal investigators in connection with the fatal 2010 pipeline explosion that leveled a San Bruno neighborhood in 2010.
The U.S. attorney in San Francisco announced the obstruction of justice charge and 27 related counts Tuesday. The new indictment replaces a previous indictment that contained 12 counts, but not obstruction.
The grand jury report accuses the utility of not only slowing the investigation but providing false or misleading information about its pipeline safety program.
Prosecutors said PG&E hampered the investigation by lying to National Transportation Safety Board investigators immediately after the blast. The other charges accuse the utility of failing to act on risks in its pipeline system even after the problems were identified by its own inspectors.
The other charges accuse the utility of failing to act on threats in its pipeline system even after the problems were identified by its own inspectors. The indictment charges PG&E with keeping shoddy records, failing to identify safety threats and failing to act when threats were found.
NTSB investigators later found that PG&E had inaccurate records on its more than 6,000 miles of gas transmission lines, and that as a result hadn't tested for the defective seam weld that ruptured a pipeline and ignited the fireball that leveled several blocks and left eight people dead in San Bruno.
No employees or executives have been charged in the San Bruno disaster. Prosecutors could still file another indictment charging individuals.
The utility announced in June that it was expecting the new indictment. PG&E spokesman Greg Snapper said company officials had not yet seen it.
"However, based on all of the evidence we have seen to date, we do not believe that the charges are warranted and that, even where mistakes were made, employees were acting in good faith to provide customers with safe and reliable energy,'' he said in a prepared statement.
The new charges expose PG&E to more than $1 billion in fines. It had preciously faced up to a $6 million fine under the old indictment.
In addition, the utility is facing lawsuits and $2.5 billion in civil fines from regulators, including the state Public Utilities Commission. San Bruno city officials on Monday demanded the head of the PUC resign, alleging the agency had improper contacts with PG&E.
Along with causing the deaths, the explosion injured dozens and destroyed 38 homes. Nearly four years later, the neighborhood about 12 miles south of San Francisco is still recovering.
"What the U.S. prosecutor is saying is that PG&E did not use the proper procedure under the law for evaluating the integrity of their pipelines,'' San Bruno City Manager Connie Jackson said. "On top of that, they represented to NTSB that the procedure they were using was correct and approved'' when it wasn't.
On Tuesday, San Bruno Mayor Jim Ruane said "the new criminal charges demonstrate a pattern of deceit by PG&E.''
PG&E said in May that it has committed $2.7 billion over the next several years for safety-related work following the incident.
Its profits were weighed down in its most recent quarter by $40 million in legal and safety improvement costs tied to its natural gas business.