This study addresses the systematic changes in laws, regulations, business cultures, and accident responses of organizations on a national level for chemical safety management after a large chemical release accident. The hydrogen fluoride leakage accident in Gu-mi City, in which 5 workers were killed and 18 were injured, has led the government to construct more practical plans and guidelines for managing and responding to chemical disasters. The governmental reorganization against chemical accidents such as Joint inter-agency The Chemical Emergency Preparedness Center, which is a specialized agency focused on responding to chemical disasters, has also contributed to the technology used in responses to chemical accidents, and as a result, it has become possible to cope with disasters more efficiently through cooperation among relevant agencies. Regarding relevant laws and regulations, the government has launched and clarified various acts and programs for the handling, management, and assessment of chemical substances and chemical-related accidents. Moreover, private enterprises have been also making efforts to systematically manage safety issues and expand high-level safety culture. In this paper, we discuss the changes in approaches to handle chemical accidents from various perspectives and present a case in which the relevant agencies succeeded in responding relatively efficiently to a major chemical accident because of these changes.