Investigative and probabilistic perspective of the accidental release of styrene: a case study in Vizag, India

Abstract

In addition to revealing the cracks in global health care, emergency preparedness, and response systems, COVID-19 also exposed the lack of capacity to run chemical plants safely under such conditions. On 7th May 2020, self-polymerization runaway reaction from an atmospheric storage tank in a polymer facility triggered the release of styrene to the atmosphere, resulting in 12 fatalities and hospitalization of more than 1000 individuals. A similar incident had happened 35 years back at Bhopal involving the release of methyl isocyanate resulting in one of the deadliest process safety incidents to date. Therefore, it is very important to understand the causal factors so that such high-risk incidents can be prevented in future. This paper presents a comprehensive investigative study of styrene gas leak at Vizag with special emphasis on probabilistic risk analysis of the loss of containment. Hazard perception study was performed to understand the possible hazardous scenarios in bulk styrene storage facilities for preventing such catastrophic recurrences. Energy barrier analysis was performed to study the inadequacy of pro-active and reactive barriers with respect to the accident case study. The analysis also considers the escalation factors resulting from extremities of COVID-19 lockdown. The self-polymerization reaction that resulted in toxic styrene dispersion was preventable owing to the advancements in safety engineering and loss prevention since Bhopal Gas Tragedy (1984). Based on the investigative analysis, it can be pointed out that this accident would have occurred even in the absence of COVID-19 restrictions, mainly due to negligence and complacency shown towards safety by the company’s management.