Safety Risks to Emergency Responders from Lithium-Ion Battery Fires in Electric Vehicles

The National Transportation Safety Board (NTSB) investigated three electric vehicle crashes resulting in postcrash fires and one noncrash fire involving an electric vehicle, all of which illustrate the risks to emergency responders posed by the vehicles’ high-voltage lithium-ion batteries. The NTSB also examined national and international standards established to maximize the safety of electric vehicles. Particular attention was given to the emergency guidance documents supplied by vehicle manufacturers to mitigate the safety risks to first and second responders who deal with electric vehicle crashes and high-voltage lithium-ion battery fires.

Fires in electric vehicles powered by high-voltage lithium-ion batteries pose the risk of electric shock to emergency responders from exposure to the high-voltage components of a damaged lithium-ion battery. A further risk is that damaged cells in the battery can experience uncontrolled increases in temperature and pressure (thermal runaway), which can lead to hazards such as battery reignition/fire. The risks of electric shock and battery reignition/fire arise from the "stranded" energy that remains in a damaged battery.