Comparative life cycle impact assessment of hazardous waste management systems: Trade-offs across waste streams, technologies, and governance

Hazardous waste management constitutes a persistent and escalating challenge at the intersection of environmental protection, public health, industrial development, and climate mitigation. This critical review synthesizes evidence across four globally consequential hazardous waste streams industrial, electronic, medical/pharmaceutical, and low‑level nuclear selected for their disproportionate contributions to human toxicity, ecotoxicity, and long‑term environmental risk. Using Life Cycle Impact Assessment (LCIA) as an integrating analytical framework, the review systematically evaluates generation patterns, logistics, treatment, disposal, and valorization pathways, with particular emphasis on tradeoffs between hazard reduction, energy demand, emissions, and resource recovery. Comparative analysis of regulatory architectures in the United States, European Union, China, and India reveals that governance outcomes depend less on formal policy ambition than on enforcement capacity, lifecycle coverage, and the integration of informal sectors. Conventional and advanced treatment technologies are critically benchmarked, demonstrating that high‑destruction solutions often shift burdens upstream or toward climate impacts unless energy and emissions are rigorously controlled. The review further assesses the emerging role of artificial intelligence in hazardous waste forecasting, routing, process control, and compliance, distinguishing validated applications from aspirational deployments. By integrating technical performance, LCIA evidence, regulatory effectiveness, and digital innovation, this review identifies conditions under which hazardous waste systems deliver net environmental benefit and outlines priority research and policy directions required to transition from risk containment toward sustainable, circular hazardous waste management. All comparative insights presented in this review are grounded in LCIA evidence and are intended to identify relative trade-offs and decision-relevant trends rather than absolute or directly comparable rankings across fundamentally different hazardous waste streams.