Abstract: Based on the case of a 100 000 m³ light oil storage tank external floating roof sinking in a chemical storage enterprise in Gulei Economic Development Zone, Zhangzhou City, Fujian Province, this article provides a detailed review of the emergency accident and fire emergency response process of the fully sunk tank. Utilizing the advantages of carbon dioxide in fire extinguishing, the article introduces the process of using carbon dioxide injection for inerting emergency response, analyzes the main risks, challenges, and considerations faced in the disposal of such accidents, and provides work inspiration and measures suggestions for the disposal of similar accidents.

Key words: fire protection, petrochemical storage tanks, external floating roof, carbon dioxide, emergency response