In the study. a methodology was developed for the determination of effect areas considering explosion, fire and toxic emissions of industrial accidents. A risk matrix was established for grading of disaster risk areas. It was tried to explain that manufacturers and control and monitoring of the relevant person or institution in charge of in which state and with which tool could be used to determine the impact area and to create a standard approach. The case studies were carried out over the same amount (13 620 kg) of toxic gases (chlorine), toxic liquids (hydrazine) and flammable substances (propane) which might pose explosion, fire and toxic emissions affects for an establishment The case studies were performed with using correlations based on offsite consequence analysis and free ALOHA software. The results of alternative scenario correlation were determined in accordance with the results obtained with the ALOHA software. Thus, it was determined that correlations required less information in order to determine effect area may be implemented in a practical way primarily. The largest endpoint distance (54.2 km-worst case scenario, 60 min, rural areas) was obtained for sample toxic liquid (hydrazine). When correlations were evaluated, all endpoint distance for rural areas were found to be higher than in urban areas. Threat zone distances were found to be not change so much in ALOHA software for rural and urban areas. The establishment was obtained at a high risk level as a result of case studies.