SAFETY
Safety investigation at acetic acid plant
In this article , the importance of valve safety measures and procedures are discussed after a fatal incident at an acetic acid plant .
By Lyndsey Denton-Fray , Valve World
About the CSB The CSB is an independent , nonregulatory federal agency whose mission is to drive chemical safety through independent investigations to protect people and the environment . CSB investigations look into all aspects of chemical incidents , including physical causes such as equipment failure , as well as inadequacies in regulations , industry standards and safety management systems .
CSB Safety Video The CSB ’ s safety video on its investigation into the fatal release of acetic acid was released in July 2024 . This video and further information can be found at : https :// www . csb . gov / csb-releases-new-safety-videoon-fatal-acetic-acid-release- /
In Valve World magazine , we publish many articles that highlight the importance of valve safety . Whether it is about the types of valves being used , selection , installation or general knowledge on how valves work , understanding and following protocol to ensure safety is paramount . That being said , sometimes things do not always go to plan .
The incident
During an attempt to isolate a pipe section between a leaking pipe and an acetic acid reactor , three contractors decided to lock a plug valve in the closed position by removing the valve ’ s actuator . However , there was not only no procedure in detailing how to remove the actuator , but the contractors were also not trained in how to remove the actuator . Instead , the contractors inadvertently removed the pressure-retaining fasteners that were holding the valve cover in place , causing the compromised valve to fail and spray all three contractors with acetic acid mixture . Two of the contractors died from their injuries .
Response and suggestions
In response to this fatal incident , the US Chemical Safety and Hazard Investigation Board ( CSB ) released a new safety video , addressing two key safety issues in their final report that contributed to the incident . The first issue addressed the design of valves to prevent human error . The CSB ’ s investigation showed that similar incidents have occurred where workers have inadvertently removed pressureretaining components from a plug valve while attempting to remove an actuator . The second issue addressed the need to provide workers with conditions , procedures and training
to safely conduct work . It was concluded that without appropriate risk assessments , maintenance tasks can be perceived as simpler than they actually are . The investigation further indicated that proper training and written procedures could have helped to prevent this incident . To address the issue of safety , suggestions were made to redesign plug valves that would make it very difficult to accidentally remove any pressure-retaining components . However , the CSB acknowledged that this is not something that can change overnight , and instead suggest that in the meantime , facilities should clearly label pressureretaining components on existing plug valves through warning signs or colour-coordination . On the issue of conditions , procedures and training , the CSB state that at some facilities a risk assessment may determine that depressurising and de-inventorying equipment is required before removing plug valve actuating equipment . Written procedures also need to be provided for workers , which will ensure that they know what to do , and if not , inform whether they are unqualified to carry out the task . Proper training and oversight of such tasks also need to be provided , lowering the risk for any misunderstandings of how the task should be carried out . With new suggestions to improve measures , there is hope that companies will follow suit and update their procedures for removing actuating equipment from plug valves . CSB board member Johnson stated that : “ As this tragic incident has shown us , even a simple task can turn deadly if it is not properly performed ,” a quote that can resonate with industries in how policy change and safety measures can help save lives .
16 Valve World February 2025 www . valve-world . net