US POWER utility Pacific Gas and Electric (PG&E) was charged on Tuesday with lying to regulators over a fatal pipeline explosion that levelled a northern California neighbourhood in 2010.
A US Attorney announced the obstruction of justice charge and 27 related counts in a new indictment charging the utility with felonies.
Prosecutors say PG&E hampered the investigation by lying to regulators immediately after the blast.
In particular, company officials are accused of telling National Transportation Safety Board investigators that safety procedures were correct and approved.
Other charges accuse the utility of failing to act on problems in its pipeline system even after they were identified by its own inspectors.
It faces hundreds of millions of dollars in fines if found guilty.
PG&E spokesman Greg Snapper said: “We do not believe that the charges are warranted and, even where mistakes were made, employees acted in good faith.”