Abstract: The toxic gases present in confined space work environments have significantly affected the physical and mental
health of the workers. To effectively prevent the hazards of toxic gases and reduce occupational health risks,and to ensure
the safety of the workers′ lives,based on the safety requirements of confined space operations,this paper analyzes the main
types and hazards of toxic gases in confined spaces,and summarizes the current development status of confined space toxic gas
control technologies from four aspects:ventilation detoxification,gas absorption,membrane separation,and individual protection.
It elaborates on the progress of toxic gas control in four typical industries:food processing industry,paper industry,farm facilities
and leather manufacturing industry,and summarizes the corresponding toxic gas control measures. The findings revealed
that:① Hydrogen sulfide,carbon dioxide,methane and carbon monoxide are common toxic gases in confined spaces,with their
distribution differing due to their physical and chemical properties. The accumulation of these gases leads to a decrease in oxygen
concentration,posing a severe threat to worker health. ② Among the methods for controlling toxic gases in confined spaces,
ventilation and gas removal,gas absorption,membrane separation,and personal protective technologies are the primary approaches.
However,in practical applications,these methods often suffer from low efficiency and limited control effects of individual
technologies. ③ Industries such as food processing,papermaking,agricultural facilities,and leather manufacturing,due to their diverse production environments and process characteristics,exhibit significant differences in the types and concentrations of
toxic gases. In these typical confined space work environments,risks such as poisoning and asphyxiation cannot be overlooked,
and the typical operations and their respective control technologies also vary. On this basis,a systematic and in-depth analysis
of the deficiencies in current toxic gas control technologies in confined space work environments is conducted,highlighting insufficient
understanding of the properties and mechanisms of toxic gases,limited effectiveness of control technologies,and low
intelligence levels of control equipment. For the period of the "15th Five-Year Plan" and beyond,research in this field should
focus on:① Deepen the theoretical research on the movement and prevention of toxic gases in confined spaces;② Continuously
conducting research on key technologies for efficient prevention and control of toxic gases in confined spaces;③ Developing integrated,automated and intelligent equipment for the prevention and control of toxic gases;④ Conducting engineering application
demonstrations of typical toxic gas prevention and control equipment for confined spaces.

Key words: confined space,toxic gases,ventilation and gas removal,gas absorption,membrane separation,personal protection