Martinez Renewable Fuels (formerly Marathon)

This page contains information related to the November 19, 2023 Major Chemical Accident/ Release (MCAR) at the Martinez Renewable Fuels (formerly Marathon) facility in which a refinery employee was severely injured and hospitalized.

Due to the serious nature of the accident, Contra Costa Health's Hazardous Materials Program commissioned a third-party Safety Culture and Management Systems evaluation of the site. This webpage will summarize the results of the third-party evaluation as well as other department activities to share details with interested parties.

Summary of the Incident

On Nov. 19, 2023 at 12:24 a.m., a recycle furnace was being started up when a tube ruptured, releasing renewable diesel directly into the furnace. This ignited a fire, which engulfed the furnace and a field operator. The fire resulted in damage to the recycle furnace and neighboring equipment and life-altering injuries to the field operator.

The refinery was in the final phase of starting up multiple pieces of equipment within a process unit called the 2 Hydrodeoxygenation (2 HDO) unit. This unit was starting up after being down for several years after being modified to process renewable fuels instead of petroleum fuels. At the time of the incident, the field operator was adjusting burner controls to address a high temperature alarm within the recycle furnace. Despite the burners being adjusted, the temperatures inside the furnace remained high until the incident occurred.

After the incident, it was found that an open chain-operated bypass valve should have been closed. The location of this bypass valve was such that it could allow product being sent to the recycle furnace to bypass the furnace. It was also found that plates remained in place on the furnace during startup that reduced the amount and location of air needed for proper combustion within the furnace. The position and location of these plates impacted the stability of the burners inside of the recycle furnace.