CARMEL, Calif. -

The city of Carmel-by-the-Sea on Monday filed a formal request for a California Public Utilities Commission investigation into PG&E's gas pipeline explosion that occurred in March.

"Carmel today asked the CPUC to expedite the completion of its investigation that has been going on since the March PG&E explosion and then immediately begin a formal investigation into what we believe are serious violations of public safety by negligence of PG&E," Mayor Jason Burnett said in a statement.

The explosion on March 3 destroyed an unoccupied home at Guadalupe Street and Third Avenue and damaged three nearby homes. There were no injuries.

Burnett said he couldn't comment on reports of a possible federal ggrand jury investigation into the Carmel explosion.

PG&E is facing federal charges stemming from a 2010 gas pipeline explosion that killed eight people in the city of San Bruno. The utility company has pleaded not guilty to a 28-count federal indictment on criminal charges in that case.