Industrial and environmental gas leaks pose serious health and environmental consequences, increasing the urgent and ongoing need for early detection and monitoring of these gases. This review critically examines the latest toxic gas detection technologies, both sensor-based and non-sensor-based, and presents their advantages and disadvantages. Unlike previous reviews, this paper provides a comprehensive comparative analysis, highlighting the most effective technologies available today and emphasizing the novel application of IoT and AI in gas detection systems. The optimal solution identified is the integration of Internet of Things (IoT) systems with artificial intelligence, enabling accurate detection and instantaneous response. Aiming to lay the foundation for the future development of more advanced and safer technologies, the study also highlights current obstacles and identifies recommendations to enhance the reliability and efficiency of these economical systems.