An analysis of CSB investigation reports for inherent safety learnings

Reports resulting from process incident investigations conducted by the US Chemical Safety Board (CSB) were analyzed for examples related to inherent safety, passive and active engineered safety, and procedural safety. These risk reduction measures, which form the hierarchy of safety controls, were also analyzed for their contribution to incident prevention and consequence mitigation, as well as their applicability to specific elements in a recognized process safety management (PSM) system. The reports examined included CSB's investigation into the Kleen Energy natural gas explosion in Middletown, CT. Widely applicable PSM elements were process and equipment integrity, training and performance, process knowledge and documentation, capital project review and design procedures, and management of change. The results were consistent qualitatively and quantitatively with that of other workers who examined incidents investigated by the CSB and other agencies. The CSB reports afford opportunities to learn and reinforce the concept of inherently safety design and its relationship to other available safety measures.