The diversity in the products manufactured by Chemical Process Industry (CPI) has made it more and more common to use reactors, conduits and storage vessels, where hazardous substances are handled at extreme conditions. The accidental release of the inventory results in toxic vapor release, fires and explosions that have potential offsite consequences. The increased public awareness towards this issue has prompted the authorities to develop tools and techniques for evaluating the risk of CPIs. Quantitative Risk Assessment (QRA) is utilized as a tool to evaluate the risk posed to the society from the process and storage facilities. For the present study, a petroleum refinery was chosen. Typically, a refinery consists of myriad chemicals that are inherently flammable, toxic and hazardous. The processing and the storage of the materials that have potential offsite consequences were analyzed. The present paper describes the hazard scenarios considered, the risk assessment procedure, selection and application of data for consequence analysis, estimating the frequency of occurrence of the event. Various changes are recommended to ensure that the risk posed to the society is within the acceptable region.

Chemicals have become a part of our life. The industries that manufacture these chemicals use various technologies that enable them to handle the raw materials at extreme conditions. At an industrial facility there are several processing plants and the inventory. If there is any catastrophic accident, then it would result in toxic vapor release/fires/explosions depending on the material properties. Along with the rapid growth of industrialization and population, the risks posed by probable accidents have also continued to rise. This is particularly so in the third world where population densities are very high around the industrial areas. The growth in the number of such industrial areas and in the number of industries in each of the areas gives rise to increasing probabilities of `chain of accidents' or cascading/domino effects, wherein an accident in one industry may cause another accident in a neighboring industry, which in turn may trigger another accident and so on. The most gruesome example of such an accident is the Bhopal Gas Tragedy of 1984 which killed or maimed over 20,000 persons; but there have been numerous other accidents like Flixborough-1974, Basel-1986, Antwerp-1987, Pasadena-1989 and Visakhapatnam-1997, etc., in which the death toll would have been as high as in Bhopal if the areas where the accidents took place were not sparsely populated.

In order to prevent or at least reduce the frequency of occurrence of such accidents, major efforts are needed towards raising the level of safety, hazard management and emergency preparedness. This realization and the increased public awareness towards this issue have prompted the authorities to develop tools and techniques for carrying out risk assessment of CPIs. There are various guidelines available in the literature (CCPS, 2000) on how to perform QRA.

Chemistry Journal, Quantitative Risk Assessment, Petroleum Refinery, Chemical Process Industry, Quantitative Risk Assessment, Hazard Management, Vapor Cloud Explosion, Storage Inventory, Catastrophic Failure, Crude Distillation Unit, Fluidized Catalytic Cracking Unit, Thermal Radiation, Propylene Recovery Unit, Horton Spheres.