Oil spills in inland freshwaters: A review of recent incidents, mitigation practices, and ecological impacts in the United States

Oil spills in inland freshwater environments remain a major but under-examined environmental challenge compared to marine disasters. This study provides the first systematic, decadal review of oil spill incidents across the United States (U.S.) from 2014 to 2024, integrating records from the federal databases such as Environmental Protection Agency, U.S. Coast Guard, and the Office of Pipeline Safety. The analysis identifies national trends in spill frequency, causes, oil types, environmental settings, and response effectiveness. More than 90% of released oil volume was in rivers, while diesel represented the most frequent spill type and crude oil contributed to the greatest cumulative volume. Transportation accidents, including vessel groundings, collisions, and equipment failures, were the leading causes, often linked to aging infrastructure and high-traffic corridors. Ecological recovery was slowest in wetlands and creeks, where hydrocarbons persist in sediments and re-mobilize during flood events. Conventional mechanical containment measures such as booms and skimmers were widely used but often limited by flow conditions and site inaccessibility. In-situ burning, recently trialed in marshes and bayous, achieved up to 90% oil removal but generated combustion residues and smoke that remain poorly characterized. The findings underscore the need for freshwater-specific response frameworks, predictive spill-risk models, and the development of environmentally safe smoke-suppressant technologies. By linking hydrological, chemical, and ecological processes, this review advances a multi-sphere understanding of oil spill dynamics in inland waters and provides a foundation for improved mitigation strategies in freshwater ecosystems worldwide.