The June 13, 2013 catastrophic equipment rupture, explosion, and fire at the Williams Olefins Plant in Geismar, Louisiana, which killed two Williams employees. The incident occurred during nonroutine operational activities that introduced heat to a type of heat exchanger called a ‘reboiler’ which was offline, creating an overpressure event while the vessel was isolated from its pressure relief device. The introduced heat increased the temperature of the liquid propane mixture confined within the reboiler shell, resulting in a dramatic pressure rise within the vessel due to liquid thermal expansion. The reboiler shell catastrophically ruptured, causing a boiling liquid expanding vapor explosion (BLEVE) and fire.

Process safety management program weaknesses at the Williams Geismar facility during the 12 years leading to the incident caused the reboiler to be unprotected from overpressure.

KEY ISSUES:
• OVERPRESSURE PROTECTION
• PROCESS HAZARD ANALYSIS
• MANAGEMENT OF CHANGE
• PRE-STARTUP SAFETY REVIEW
• OPERATING PROCEDURES
• HIERARCHY OF CONTROLS
• PROCESS SAFETY CULTURE

ROOT CAUSES:
1. Williams did not perform the 2001 MOC until after the plant was operating with the valves installed, and the associated PSSR was incomplete. These actions did not comply with facility (and regulatory) safety management system requirements; however, Williams management accepted both of these practices;
2. Car seals are low-level, administrative controls, but they were the favored safeguard in the 2006 PHA recommendation to prevent overpressure events. Williams Geismar did not have a policy requiring the effectiveness of safeguards to be analyzed;
3. Williams Geismar did not follow OSHA PSM regulatory requirements that operations activities have an associated procedure to safely conduct the work. For example, Williams did not create a procedure specifically for switching the propylene fractionator reboilers Such a procedure should have alerted the operations personnel of the overpressure hazard;
4. The Williams PHA policy did not require effective action item resolution and verification, resulting in incorrect action item implementation in the field;
5. The Williams PHA policy did not require PHA teams to effectively evaluate and control risk; and
6. Operations personnel had informal authorization to manipulate field equipment as part of assessing process deviations without first conducting a hazard evaluation and developing a procedure.

Image & AcciMap Credit: CSB