State regulators say Pacific Gas & Electric Co. put the public at risk by allowing its pipelines in cities throughout Northern and Central California to run at the wrong pressure levels.

A staff report issued Friday by the California Public Utilities Commission says the company wrongly classified hundreds of miles of natural gas transmission lines of the same type that blew up in the deadly explosion in San Bruno.

Regulators says that means PG&E broke state pipeline safety rules thousands of times, because federal law requires utilities to perform more stringent inspections on lines in densely populated areas.

PG&E spokesman Dave Eisenhauer says the company is reviewing the report.

PG&E already faces millions in fines in the wake of the Sept. 9, 2010 blast, which killed eight people and destroyed three dozen homes.