Background: One of the substances with a high potential of damaging that nowadays is used widely in industry and human environment is LPG gas cylinders. Aim: The purpose of this study is modeling the consequences of gas leakage in domestic cylinders containing LPG (Liquefied petroleum gas). Subjects and Methods: The factors affecting discharging and emissions of LPG gas in 26, 60, 78 and 107 liter cylinders were described. ALOHA software was used as one of the best software for modeling gas emissions from tank storage, and emergency response program was presented at the time of the gas leakage based on modeling results. Results: The results showed that in all 4 types of examined cylinder up to distance 11 meters around the tank of LPG gas, concentration of gas is 33000 ppm. This area is located in the AGEL-3 that there is the risk of death and threatens the lives of people. In case of full gas leakage from 60, 78 and 107 liters cylinders, respectively at the distance of 11, 12 and 16 meters from cylinders, concentration of gas was about 21,000 ppm that was equal to low explosive limit (LEL). In full gas leakage, the consequences of combustion and explosion of LPG gas to distance 15 meters of cylinder is the most serious danger that threatens the personnel. Conclusion: Developing an emergency response plan is essential and will have an important role in limiting the harmful effects in release of gas and hazardous substances.