Integrated PSM Framework for Hazard Identification, Risk Assessment and Consequence Analysis of Chlorine Handling Operations in Chemical Process Industries

Abstract

Chlorine is one of the most extensively used hazardous chemicals in the chemical process industry due to its vital role in the production of bleaching agents, disinfectants, plastics, synthetic rubber, pharmaceuticals, agrochemicals, water treatment chemicals, and numerous industrial intermediates. Despite its widespread industrial applications, chlorine is highly toxic, corrosive, and reactive, making its storage, transportation, and handling a significant process safety challenge. Even a minor accidental release can result in severe consequences, including toxic exposure, environmental contamination, equipment damage, and potential fatalities. Therefore, systematic hazard identification, quantitative risk assessment, consequence analysis, and effective mitigation strategies are essential to ensure safe chlorine handling operations. The present study focuses on the assessment of process safety risks associated with chlorine handling in a chemical process industry using an integrated Process Safety Management (PSM) approach. The research involves the identification of potential hazards throughout the chlorine handling system, including storage cylinders, pipelines, valves, vaporizers, and transfer operations. Hazard identification techniques such as structured checklists, workplace observations, document review, and questionnaire-based surveys were employed to identify unsafe acts, unsafe conditions, equipment failures, and human error that may lead to accidental chlorine releases. The identified hazards were further analyzed using qualitative and quantitative risk assessment techniques to evaluate the probability of occurrence and the severity of their consequences. Consequence analysis was carried out using ALOHA (Areal Locations of Hazardous Atmospheres) software to simulate different accidental chlorine release scenarios under varying meteorological conditions. Worst-case and alternative release scenarios were analyzed to estimate toxic dispersion distances, threat zones, exposure levels, and potential impacts on workers, nearby communities, and the surrounding environment. The effectiveness of various passive and active mitigation measures, including scrubber systems, water spray curtains, ventilation, emergency shutdown systems, confined storage arrangements, and leak detection systems, was evaluated to reduce the consequences of accidental chlorine releases. The study also examines the effectiveness of emergency preparedness and response planning by incorporating atmospheric dispersion modelling, exposure assessment, building air infiltration considerations, and emergency response strategies such as shelter-in-place, controlled evacuation, emergency communication, and incident command procedures. The influence of environmental parameters such as wind speed, atmospheric stability, release quantity, and release duration on toxic cloud dispersion was also investigated to understand their impact on emergency response planning and risk reduction. Based on the findings of the risk assessment and consequence analysis, appropriate engineering controls, administrative controls, operational procedures, inspection and maintenance practices, employee competency development, and emergency preparedness measures have been recommended to strengthen the Process Safety Management system. The proposed mitigation strategies are intended to minimize the probability of chlorine release incidents, reduce occupational health and environmental risks, improve regulatory compliance, and enhance overall industrial safety performance. The outcomes of this research provide a practical framework for risk identification, consequence assessment, and mitigation planning for chlorine handling operations in chemical process industries. The study demonstrates that integrating Process Safety Management principles with hazard identification techniques and ALOHA-based consequence modelling significantly improves decision-making for accident prevention, emergency planning, and sustainable industrial safety management. The proposed methodology can also be adapted for the risk assessment of other hazardous chemicals handled in process industries.