ABSTRACT
Consequence analysis of toxic chemicals releases has important influence on emergency response planning and reduction of fatalities. To determine consequences of toxic chemicals releases in petrochemical feed and product pipelines network. This was a cross-sectional study performed in Mahshahr Petrochemical Special Economic Zone [Petzone, Iran] during 2006-2007. Initially, a total number of 60 pipelines were evaluated using the chemical exposure index and the most hazardous chemicals selected for further analysis. Later, the lethal concentrations of chemicals were calculated by probit equation and local meteorological data assessed. In the end, the toxic release dispersion modeling was performed using of areal location of hazardous atmospheric program, and the fatal length for emergency response planning offered. Butadiene pipeline showed the highest chemical exposure index value however, the chlorine pipeline was found to have the most hazard distance based on life-threatening health effects of emergency response planning guideline [ERPG-3]. The LC1, LC50 and LC99 in F condition were about 703m, 413m and 248m, respectively. Determination of hazard distance and emergency response planning for chlorine pipeline based on LC1 and in F condition will supply the lowest level of fatality and highest margin of safety in areas adjacent to petrochemical feed and product pipelines network