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Why must used batteries be collected and recycled through controlled systems?

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Cross-section diagram of an alkaline-manganese dioxide battery showing labeled internal components, including the steel-plated covers, cathode, anode gel, current collector, separator, steel can, and brass rivet. — battery Cutaway view of an alkaline–manganese dioxide power cell.

Used batteries must be collected and recycled through controlled systems to mitigate significant environmental and health risks. Many batteries contain heavy metals—such as lead, cadmium, and mercury—and reactive chemicals that are toxic to the environment and human health. If disposed of improperly, these substances can leach into the ecosystem, causing long-term harm.123

Furthermore, many battery types pose physical safety hazards. For example, lithium batteries are sensitive to high temperatures and can experience "thermal runaway," a condition where the cell may smoke or catch fire. Other systems, such as those using thionyl chloride, contain corrosive and toxic materials that can release harmful gases if the battery is opened, burned, or damaged.4

Controlled recycling chains, which involve authorized recyclers and formal collection channels, are essential to ensure these materials are handled safely, preventing the release of poisons and reducing the risk of fire or chemical exposure. Establishing these systems is a matter of ethical responsibility, as it protects public safety and preserves the environment from the hazardous waste generated by modern electronic devices.143