BATTERY FIREWATER AS AN EMERGING ENVIRONMENTAL HAZARD: EVIDENCE SYNTHESIS AND THE C5 CONTAINMENT–TREATMENT FRAMEWORK FOR LITHIUM-ION BATTERY INCIDENTS

The rapid deployment of lithium-ion batteries in electric vehicles, stationary energy-storage systems, consumer products and waste streams has created an environmental problem that is insufficiently integrated into conventional fire-safety practice: contaminated firefighting runoff. Water remains one of the most important suppression and cooling media for lithium-ion battery incidents, yet contact with thermally damaged cells, combustion products and deposited particulates can generate a chemically complex wastewater containing fluoride, lithium, nickel, cobalt, manganese, copper, aluminum, organic electrolyte residues, soot-associated contaminants and per- and polyfluoroalkyl substances. This structured critical review synthesizes experimental, ecotoxicological, toxicological and field evidence available through September 2026 and organizes it using a source–pathway–receptor model. The evidence indicates that environmental risk is governed not simply by battery chemistry but by incident scale, state of charge, degree of cell rupture, suppression method, water volume, internal flushing, post-fire immersion, drainage connectivity and containment. The study introduces the five-stage C5 framework—Contain, Characterize, Classify, Clean and Confirm—and a four-level B0–B3 incident classification to translate evidence into operational decisions. A contaminant-oriented treatment architecture combining solids separation, precipitation/coagulation, ion exchange or adsorption, membrane polishing and controlled residual management is proposed. Battery firewater should be treated as potentially contaminated industrial wastewater until site-specific characterization demonstrates an appropriate disposition route. The framework connects battery fire safety, emergency response, environmental engineering and water-quality management without discouraging essential life-safety suppression.