HHS developed an intelligent IoT system that combines bio-signal processing technology and complex sensing technology in order to analyze and monitor workers' individual risk status and health in real time for the four most common accident types (fall, bump, suffocation, and heat-related illness) that occur in ultra-high-risk workplaces. This system provides a data-based integrated worker safety management service that determines risks through analysis of workers' individual movement patterns and EEG analysis technology and combines harmful gas detection technology using IoT sensor arrays.