CSB Issues Final Study on 2013 Williams Geismar Explosion

October 21, 2016

4 Min Read
CSB Issues Final Study on 2013 Williams Geismar Explosion
The reboiler at Williams Olefin's Geismar, LA plant, which ruptured and exploded in 2013, killing two. Image courtesy of CSB

The U.S. Chemical Safety Board (CSB) issued its final case study on cause of the explosion and fire at a Williams Olefins facility in Geismar, LA on June 13, 2013 that killed two workers and injured 167 others on Wednesday, placing blame for the incident on lapses in the site’s process safety management program.

“The report concludes that process safety management program deficiencies at the Williams Geismar facility during the 12 years leading to the incident allowed a type of heat exchanger called a ‘reboiler’ to be unprotected from overpressure, and ultimately rupture, causing the explosion,” said the CSB, , a non-regulatory federal agency that investigates chemical accidents, in a press release announcing the release of the study.

The incident at the Williams plant, which makes ethylene and propylene for petrochemical industry uses, happened during “non-routine” operations, according to the CSB, when heat was introduced to an offline boiler that was isolated from its pressure relief device. As a liquid propane mixture in the boiler heated up, pressure increased and the vessel ruptured, the organization said, resulting in a boiling liquid expanding vapor explosion (BLEVE) and fire.

The CSB’s investigation determined that the Williams facility had a “poor process safety culture” and identified significant shortcomings in the implementation of Management in Charge (MOC), Pre-Startup Safety Review (PSSR), Process Hazard Analysis (PHA), and procedure programs that the organization said contributed to the incident:
- Failure to appropriately manage or effectively review two significant changes that introduced new hazards involving the reboiler that ruptured – (1) the installation of block valves that could isolate the reboiler from its protective pressure relief device and (2) the administrative controls Williams relied on to control the position (open or closed) of these block valves.
- Failure to effectively complete a key hazard analysis recommendation intended to protect the reboiler that ultimately ruptured.
- Failure to perform a hazard analysis and develop a procedure for the operations activities conducted on the day of the incident that could have addressed overpressure protection.

“The tragic accident at Williams was preventable and therefore unacceptable. This report provides important safety lessons that we urge other companies to review and incorporate within their own facilities,” said CSB chairperson Vanessa Allen Sutherland in a statement.

According to the CSB, the incident and its investigation highlights the importance of:
- Using a risk-reduction strategy known as the “Hierarchy of Controls” to effectively evaluate and select safeguards to control process hazards. This strategy could have resulted in Williams choosing to install a pressure relief valve on the reboiler that ultimately ruptured instead of relying on a locked open block valve to provide an open path to pressure relief, which is less reliable due to the possibility of human implementation errors;
- Establishing a strong organizational process safety culture. A weak process safety culture contributed to the performance and approval of a delayed MOC that did not identify a major overpressure hazard and an incomplete PSSR;
- Developing robust process safety management programs, which could have helped to ensure PHA action items were implemented effectively; and
- Ensuring continual vigilance in implementing process safety management programs to prevent major process safety incidents.

In the wake of the 2013 explosion and fire, Willaims Olefins made improvements in process safety management at the Louisiana facility, including redesigning reboilers to prevent isolation from pressure relief valves, creating a more collaborative mode of managing its change process, and revamping its process hazard analysis procedure.

“Williams made positive safety management changes at the Geismar facility following the incident, but more should be done to improve process safety and strengthen the plant’s process safety culture,” said CSB investigator Lauren Grim in a statement. “Our report details important safety recommendations to protect workers at the Williams Geismar facility.”

In addition to a number of safety recommendations for the Geismar facility offered by the CSB, the agency also said it had identified flaws in an important industry standard on “Pressure-relieving and Depressuring Systems” from the American Petroleum Institute (API), and suggests changes to the standards that it said may help safeguard against future similar incidents.

“Most of the accidents CSB investigates could have been prevented had process safety culture been a top priority at the facility where the incident occurred,” said chairperson Sutherland. “These changes must be encouraged from the top with managers implementing effective process safety management programs.” 

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