Li-ion batteries are stable when maintained within charging parameters. However, if they are damaged or subjected to intense heat, these batteries present a unique combination of electrochemical hazards that can challenge first responders.

• Li-ion batteries contain electrolyte: a hazardous material that has explosive potential when heated. An internal short-circuit or external event can cause the electrolyte to vaporize, build internal pressure, and release a mixture of toxic and flammable gases.
• Electrolyte gases will explode when confined in concentrations within the flammable range. Recent utility-scale incidents have injured and killed firefighters who were in proximity to such explosions.
• Once ignition occurs, mitigation requires a long-term, resource-intensive effort. Batteries retain stranded energy and have been known to reignite several days after initial suppression.