The August 4, 2020 explosion in Beirut port, Lebanon, was a national level catastrophe. Ammonium nitrate is at the center of this accident, as revealed by the accident investigation and fire investigation at the UN/OECD level. Ammonium nitrate is classified as First-class oxidizing soilds, ‘nitrates’, under the Act on the safety control of dangerous substances and is managed with a ‘specified quantity of 300kg’ and classified as Third-class oxidizing solids, under global standards such as UN GHS and TDG. The purpose of this study is to analyze the mechanisms of major accidents by ammonium nitrate, research ammonium nitrate safety management systems in major countries, and compare the oxidizing hazard of ammonium nitrate by use types. Through this study, it is expected that it can be used as basic data to understand the type of fire caused by ammonium nitrate when identifying heat source or fire mechanism at the fire site because it is widely used in our daily lives without being aware of it.