This study focused on a novel approach for classifying hazardous chemicals to be used for chemical terrorism. We developed a novel algorithm to classify nationally customized chemicals of interest (COI) out of 325 COI in USA. The proposed COI classification algorithm aims to identify a key set of factors that reflect nation-wide uniqueness: intentional use, objectives, toxicity, related laws (CWC, ITF-25, CAA, etc.) and responsive counter-actions to terrorism. Although the U.S. has managed 325 COI to prevent terrorism, there are some nations in which the management and control of all the hazardous chemicals are beyond their capability. Based upon the outcome of this study the Ministry of the Environment of Korea has made appropriate revisions on relevant law. As a result, the Korean government has officially added a new set of 13 chemical species to the list of existing hazardous chemicals. This work is worthwhile to contribute to protecting the people’s lives and property from possible chemical accidents including terror by chemicals.