Sempra Energy’s natural gas utilities are accused of essentially cooking the books on a critical north-south transmission pipeline by inaccurately reporting safety information, according to the independent consumer advocacy unit of the California Public Utilities Commission (CPUC).

The Office of Ratepayer Advocates (ORA) is asking the five-member CPUC to require Southern California Gas Co. (SoCalGas) and San Diego Gas and Electric Co. (SDG&E) to explain alleged inaccuracies in the safety records of Line 1600, the 16-inch diameter pipeline that runs from the Rainbow metering station in Fallbrook, CA, to mission base at the northern end of San Diego. Line 1600 runs for nearly 50 miles, 33 of which are in densely populated areas.

In the motion to CPUC, ORA claimed it has evidence that the two utilities violated federal safety regulations that are designed to ensure safety in communities in which major high-pressure pipelines traverse.

“By way of its motion, ORA has identified for the CPUC yet another example of SoCalGas/SDG&E’s inaccurate Line 1600 safety data,” an ORA spokesperson said. ORA said it has unsuccessfully sought information from the utilities about the frequency of inspections on Line 1600, which is nearly 70 years old.

“So far, the utilities have refused to provide this required safety information,” the spokesperson said.

ORA asked CPUC to hold the utilities accountable and “improve its poor recordkeeping on Line 1600.”

Separately on Thursday, the CPUC rejected a long-standing proposal by SoCalGas and SDG&E to build a $639 million, 36-inch diameter transmission line to replace Line 1600.

California regulators a few days ago launched an investigation related to long-term outages on some of SoCalGas’ major transmission pipeline branches at the same time it was moving to increase withdrawals from the Aliso Canyon underground storage facility north of Los Angeles, which is operating at less than a third of its normal 86 Bcf capacity.

SoCalGas has been asked to provide to CPUC by next June 29 information on the pipelines as regulators consider an investigation and assess utility rate adjustments for the prolonged downtime for the transmission lines. The major focus is on Line 3000, which has been down since July 2016, and Line 235-2, which ruptured last October.