Despite the requirement that gas distribution systems conduct leak surveys pursuant to 49 CFR 192.723 (annually in business districts, every three years for bare steel lines, and every five years for the remaining lines), Pacific Gas & Electric (PG&E) found it had not properly leak surveyed 13.83 miles of suburban distribution mains and 1,125 service lines and that some of the mileage had not been tested for 19 years.

Unclear company standards and a lack of quality control were cited as the potential cause. PG&E, which is one of the largest combination natural gas and electric utilities in the United States, self-reported its discovery and that it had repaired the 22 leaks found during their post-discovery survey, including 14 Grade 3 leaks, five Grade 2 leaks, two Grade 2+ leaks, and one Grade 1 leak. Regardless, the California Public Utility Commission (CPUC) proposed a $16.76 million fine for this failure because of the duration and seriousness of the violation.