Pacific Gas and Electric Co. has pleaded not guilty to federal safety violation charges stemming from a deadly 2010 natural gas pipeline explosion in the San Francisco Bay Area.

PG&E entered the plea in San Francisco on Monday to 12 felony violations of federal pipeline safety laws. Federal Magistrate Judge Joseph Spero granted prosecutors' request to increase the maximum fine PG&E faces to more than $6 million.

Prosecutors allege that PG&E knowingly relied on erroneous and incomplete information when assessing the safety of the pipeline that eventually ruptured and sparked a fireball in a San Bruno neighborhood. Eight people died and dozens were injured. Thirty-eight homes were destroyed.

PG&E said in a statement it doesn't believe any employee intentionally violated federal pipeline safety regulations.