After two previous reports that were highly critical of Pacific Gas & Electric's natural-gas pipeline operations in the fatal 2010 San Bruno blast, its pipeline network and its record-keeping, the utility received another report that may turn out to be the most critical and the most costly of all.

The California Public Utility Commission's Consumer Protection and Safety Division (CPSD) released its incident investigation report on Jan. 12. It alleged PG&E violated the Public Utilities Code and federal and state pipeline safety regulations and failed to follow accepted industry standards.

On Sept. 9, 2010, a 30-in.-dia PG&E natural-gas transmission pipeline ruptured and ignited in San Bruno, resulting in eight deaths, 58 injuries and the destruction of 38 homes. Since then, the National Transportation Safety Board and independent review-panel reports have cited the utility for its failures and mismanagement.

The CPSD investigation and the other reports reached similar conclusions. For example, PG&E caused the incident by not following accepted industry practice when constructing the section of pipe that failed. The utility kept inadequate records. It failed to comply with integrity management requirements. PG&E's Supervisory Control and Data Acquisition System was deficient. There were inadequate procedures to handle emergencies and abnormal conditions, and the utility's emergency-response actions after the incident were deficient. The report cited PG&E's systemic failure to emphasize safety over profits.

The report foreshadows a formal enforcement action, leading to possible penalties and other remedies, according to CPSD. Terrie Prosper, a commission spokeswoman, said an administrative law judge will be appointed but that no date has been set.