Washington — Chemical facility operators need to ensure workers remain at a safe distance from fired heaters when tube temperatures are high, the Chemical Safety Board says in its final report on a November 2023 fire.
The fire occurred at the Marathon Martinez Renewables facility in Martinez, CA. One worker sustained third-degree burns on much of his face and body during the incident, which also contributed to about $350 million in property damage.
CSB investigators found that a refinery furnace overheated, resulting in the blaze. With the furnace malfunctioning, the worker was sent to turn off part of the machinery. A metal tube in a fired heater ruptured, however, creating dangerously high temperatures and releasing renewable diesel and hydrogen that ignited the fire.
The agency determined that the tubes overheated because an open valve diverted a “significant amount of process flow” away from the fired heater. Additionally, cover plates blocked the air inlets of two of the four burners.
To prevent future incidents, CSB recommends that chemical facilities establish requirements “for when troubleshooting in close proximity to fired heaters should be stopped and other actions, such as shutting down a fired heater remotely, should be taken.”
Other lessons for the industry:
- Configure process equipment with safe operating limit/not-to-exceed limit alarms that alert workers that equipment has reached an unsafe condition, troubleshooting efforts need to end, and predetermined actions must be taken quickly to shut down or return equipment to a safe state.
- Ensure fired heaters are adequately protected from operating with low flow.
- Fired heaters should be equipped with continual combustibles monitoring at the bridgewall to detect the onset of incomplete combustion.
- To minimize equipment lineup errors, employers should implement “walk the line” practices such as verifying valve positions before starting up a unit, understanding operating procedures and equipment routings, and properly communicating and documenting shift turnover information.
- Employers should have effective oversight to ensure processes and equipment are safe and workers are adequately trained and prepared before startup of a new or revamped process.
“This tragic event underscores the importance of having proper safeguards in place for fired heater operation, which can be particularly hazardous,” CSB Chair Steve Owens said in a press release. “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.”
