Abstract: Chemical production accidents are often accompanied by toxic substance leakage and combustion, triggering cross-media secondary pollution involving the atmosphere, water bodies and soil. Due to the complex characteristics of multiphase interactions and cross-media migration, such pollution poses serious threats to ecological security and public health. Based on the physicochemical properties of secondary pollutants in chemical accidents, this paper ?systematically analyzes their transmission mechanisms, monitoring & early warning technologies and risk assessment methods. On this basis, a multi-media emergency prevention and control system framework is constructed. Through empirical case analysis, comprehensive control strategies integrating multi-scale coordination, spatiotemporal dynamics, and multi-agent collaboration are proposed. The research further outlines future development directions from technical integration and policy-management perspectives. This provides theoretical framework and practical pathways to enhance emergency management effectiveness in chemical accidents.

Key words: chemical accident, multi-media pollution, emergency prevention and control, risk assessment, monitoring and early warning