Long before a natural gas storage well sprung a disastrous leak near Los Angeles, utilities and national industry groups were raising alarms about the danger of aging underground storage infrastructure.

The leaking well's owner, Southern California Gas Co. warned state utility regulators in 2014 of "major failures" without a rate hike to pay for comprehensive inspections of 229 storage wells.

Twenty-six of its wells were "high risk" and should be abandoned — even though they complied with state regulations, the utility wrote in a rate filing.