The pipeline, a crude oil pipeline, is reported to have been abandoned is under the jurisdiction of the State Fire Marshall. Based on California State law, this type of pipeline is not overseen by the California Department of Conservation, Department of Oil, Gas, and Geothermal Resources (DOGGR) the agency responsible for overseeing oil and gas operators in the state.
From the Office of the State Fire Marshall Website:
"In 1981, the California Legislature established the Hazardous Liquid Pipeline Safety Act with the intent that the Office of the State Fire Marshal (OSFM) shall exercise exclusive safety regulatory and enforcement authority over intrastate hazardous liquid pipelines. The Office of the State Fire Marshal currently regulates the safety of approximately 4,500 miles of intrastate hazardous liquid transportation pipelines. The Pipeline Safety Division consists of engineers, analytical staff, and clerical support located in northern, central and southern California. Pipeline Safety staff inspect pipeline operators to ensure compliance with federal and state pipeline safety laws and regulations. The Division is also responsible for the investigation of all spills, ruptures, fires, or pipeline incidents for cause and determination of probable violations."
Here is a map from the OSFM website of the crude oil pipelines in the state: