Contra Costa Supervisors Approve Final Environmental Report For Marathon Martinez Biofuel Conversion

In a quick unanimous vote taken before its lunch break Tuesday, the Contra Costa County Board of Supervisors approved the final environmental impact report for Marathon Martinez Refinery’s conversion from an oil refinery into one that handles renewable fuels. No one from the public spoke about the project, which was contentious when the board initially signed off on its land permit and initial EIR in May 2022. The following month, environmental groups Communities for a Better Environment and the Center for Biological Diversity filed a lawsuit to block the conversion, challenging what they called “flawed environmental review processes for two giant oil refineries looking to convert from processing crude to producing biofuels from vegetable oil and animal fat feedstocks.” The second refinery was Phillips 66 in Rodeo, planning to undergo a similar transformation that the supervisors also approved, prompting another lawsuit. The county reapproved a new EIR for the Phillips project in January 2024 after the county clarified questions raised by the judge. Once transformed, the Martinez refinery east of Interstate Highway 680 and south of Pacheco Marsh would produce diesel fuel from renewable sources, including rendered fats, soybean and corn oil, and other cooking and vegetable oils.

According to a staff report for Tuesday’s meeting, the judge presiding over the lawsuit concluded the 2022 EIR was adequate on all counts, except for its discussion and deferral of odor mitigation and told the county to reconsider the mitigation measures for odor impacts. New odor sources were identified as organic vapors generated by the storage of renewable feedstock. The new EIR identified ways to mitigate the odor. Marathon will alter and/or replace refinery equipment and install new equipment and tanks. Crude oil processing equipment that can’t be repurposed would be shut down and removed.

Opponents have also said the county wasn’t mitigating other significant environmental problems the project could cause, as well as ones left over by more than 100 years of oil refining at the site. Supervisors acknowledged their concerns in 2022, but said Marathon planned their proposal carefully. They also said helping California convert from fossil fuel consumption to that of renewable diesel fuel took priority — at least to bridge the coming years until all vehicles can run on electricity.