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Summary

On June 13th, 2013, a tragic explosion at the Williams Geismar Olefins Plant in Louisiana killed two workers and injured many others. The Chemical Safety Board (CSB) investigation revealed several process safety management failures, including improper valve installation and inadequate safety reviews. The explosion was caused by overpressure in a reboiler, which had been isolated from its protective pressure release valve. The CSB's findings underscore the importance of detailed safety assessments and the need for robust process safety management programs to prevent similar incidents in the future.

Takeaways

• 😀 On June 13th, 2013, a heat exchanger rupture at the Williams Geismar Olefins Plant in Louisiana caused an explosion and fire, resulting in two fatalities and 167 injuries.
• 🔥 The Chemical Safety Board (CSB) identified critical deficiencies in the plant's process safety management program that contributed to the incident.
• 🔧 The heat exchanger involved in the explosion was isolated from its pressure release valve, which allowed pressure to build up to catastrophic levels.
• 📅 The incident was linked to changes made in 2001, where valves were installed on reboilers to allow for operation of one at a time, which introduced a serious safety hazard.
• ⚠️ The CSB found that liquid propane had accumulated in the standby reboiler, which was unknowingly heated by hot water and led to the explosion due to pressure buildup.
• 🛠️ Williams did not conduct a comprehensive safety review or properly assess the impact of the valve installation, which resulted in the overpressure hazard being overlooked for over a decade.
• 🔍 Inadequate process hazard analyses (PHAs) failed to identify the risk of reboiler overpressure, even though recommendations were made to address the issue but were not implemented correctly.
• 📑 The company’s pre-startup safety review (PSSR) was incomplete, leaving critical questions about pressure release systems unanswered, which contributed to the unsafe conditions.
• 📝 A key lesson from the incident is the importance of paying attention to small details in safety programs, as missed details can lead to catastrophic events years later.
• 🚨 The CSB recommended that Williams improve its safety culture and establish a robust system for tracking and improving safety indicators to prevent future incidents.

Q & A

What caused the explosion at the Williams Geismar Olefins Plant on June 13th, 2013?

The explosion was caused by a heat exchanger that ruptured due to overpressure. The standby reboiler was isolated from its protective pressure release valve, and when hot water was introduced, it heated liquid propane that had accumulated inside the reboiler. This caused a dangerous pressure buildup, leading to the catastrophic failure.

What was the role of the heat exchangers, or 'reboilers', in the Williams Geismar plant?

The reboilers supplied heat to the propylene fractionator, which is a distillation column. Their primary function was to vaporize propane and propylene to aid in the separation process of these chemicals, which are key to producing ethylene and propylene.

How did fouling in the reboilers contribute to the incident?

Fouling, caused by oily tar buildup inside the reboiler tubes, reduced the efficiency of the reboilers. This necessitated periodic shutdowns to clean the tubes. During the incident, fouling in the operating reboiler led to a drop in water flow rate, which prompted the attempt to switch to the standby reboiler.

What was the safety issue introduced by the installation of new valves in 2001?

The new valves installed in 2001 allowed only one reboiler to operate at a time. However, these valves isolated the standby reboiler from its pressure release valve, preventing the reboiler from being safely vented if overpressurized, creating a serious hazard that went unaddressed.

Why was the pressure release valve not able to prevent the explosion?

The pressure release valve was rendered ineffective because the standby reboiler had been isolated from it by closed block valves. As a result, when propane inside the reboiler was heated, the pressure increased without any relief, leading to the explosion.

What was the role of the Operations supervisor on the day of the incident?

The Operations supervisor noticed a decrease in water flow through the operating reboiler and went into the plant to investigate. He decided to open the valves on the standby reboiler to allow hot water to flow through, unaware that propane had accumulated inside the reboiler, leading to the overpressure and subsequent explosion.

What safety procedures were overlooked during the installation of the new valves and reboiler operation?

Williams failed to conduct a thorough Management of Change (MOC) review before installing the new valves, which could have identified the hazard of isolating the standby reboiler from its pressure release valve. Additionally, the pre-startup safety review was incomplete, leaving critical safety questions unanswered.

What were the key findings of the CSB investigation regarding process safety management at the plant?

The CSB found that a series of process safety management deficiencies led to the explosion. These included inadequate hazard analyses, incomplete safety reviews, and failure to identify and mitigate the overpressure hazard introduced by the new valve installation.

What were the human consequences of the explosion at the Williams Geismar plant?

The explosion killed two workers, the Operations supervisor and an operator. Additionally, 167 other employees and contractors were injured in the incident.

What recommendations did the CSB make to prevent future incidents like the one at Williams Geismar?

The CSB recommended that Williams improve its safety culture through workforce participation, develop a robust safety indicators tracking program, and perform comprehensive assessments of the facility’s process safety programs. They also stressed the importance of identifying and addressing process hazards in safety reviews and analyses.