The Los Angeles County Board of Supervisors has sent a letter to state regulators, urging them to deny the request by Southern California Gas Co. to resume injection of natural gas into its Aliso Canyon underground storage facility.

SoCalGas has proposed restoring operations at Aliso Canyon, the largest such facility in the state, following extensive repairs in the wake of a four-month gas leak that displaced thousands of residents.

In a unanimous vote, the supervisors approved sending the letter to the California Public Utilities Commission and the Division of Oil, Gas and Geothermal Resources (DOGGR). It calls for a postponement of injection until the agencies have determined the cause of the leak and determined that the facility is both safe to operate and necessary to supply the region’s needs for natural gas.

SoCalGas has completed extensive testing of most of the wells in the field, and has installed new casing and pipelines at wells that it plans to use for injection and recovery of gas. It also has added new around-the-clock monitoring as well as automated methane detection equipment.

The utility has proposed resuming operations as soon as final testing is completed. In a letter to the Supervisors, it said that “the Aliso Canyon storage facility is fit for service and safe to resume injections,” and that delays “would increase the risk of energy shortages in L.A. County.”

The final decision about resuming operations at the facility will be made by DOGGR and the PUC.