CSB Calls for Stronger Fired Heater Safety After Major Fire at Martinez Facility

A devastating fire at the Marathon Martinez Renewables facility in California has prompted federal safety officials to call for stricter safeguards around fired heater operations in chemical plants.

Incident Overview

In November 2023, a serious fire broke out at the Martinez, CA facility, leaving one worker with third-degree burns on much of his face and body. The incident also caused an estimated $350 million in property damage.

The fire was triggered when a metal tube inside a fired heater ruptured, releasing renewable diesel and hydrogen that ignited under extreme temperatures. At the time, a worker had been sent to manually shut down part of the malfunctioning equipment.

Investigation Findings

The U.S. Chemical Safety Board (CSB) determined that the rupture and resulting fire were caused by a series of operational failures:

• A valve had been left open, redirecting a significant amount of process flow away from the heater, leading to dangerous overheating.
• Airflow was compromised by cover plates blocking the air inlets of two out of four burners.

These conditions led to excessive tube temperatures and ultimately to the equipment failure.

Recommendations for Industry

In its final report, the CSB emphasized the need for chemical facilities to implement stricter controls and decision-making processes when dealing with fired heaters:

• Establish clear criteria for when troubleshooting near fired heaters should stop, and when remote shutdowns should be used instead.
• Install safety alarms to alert workers when equipment approaches or exceeds safe operating limits.
• Equip fired heaters with safeguards against low-flow operations.
• Implement continuous monitoring for incomplete combustion using combustibles detection at the bridgewall.
• Adopt “walk the line” procedures to verify valve settings, understand process flows, and improve communication during shift changes.
• Ensure robust oversight, training, and preparedness before launching new or modified processes.

CSB Statement

CSB Chair Steve Owens commented on the gravity of the event, stating:

“This tragic event underscores the importance of having proper safeguards in place for fired heater operation, which can be particularly hazardous. A series of safety failures contributed to the severity of this incident, including the lack of appropriate guidance for when to shut down the heater remotely instead of putting a worker at risk of harm.”

Photo credit: CSB. All rights reserved. Post-incident as-found condition of the air side of four of the burners.