The California Public Utilities Commission has fined Pacific Gas & Electric $530,000 for safety violations it says it found during audits that began in 2012.
The commission says in a Friday statement that the fines include $430,000 for failing to immediately examine pipelines and showed signs of potential corrosion.
It says PG&E has also been fined $100,000 for allowing non-qualified workers to perform field work.
The commission says the violations could create hazardous conditions for the public and utility employees.
Allegations of back-channel dealings between the state commission and PG&E surfaced last year after emails showing officials privately discussing regulatory matters were made public.
The utility has 10 days to pay or dispute the citations.