Key Takeaways
During Florida’s recent seasonal hurricanes, electric vehicles and other battery-powered transport devices went up in flames as their batteries were exposed to saltwater storm surges.
Lithium-ion batteries do not react well to salt water, creating electrical shorts that can reveal themselves even weeks after the exposure.
Because the batteries produce their own oxygen while burning, they can take enormous amounts of water to extinguish, and the fires are extremely hot.
Some electric vehicle (EV) owners in Florida experienced their cars igniting as salty storm surges from Hurricanes Helene and Milton caused the lithium-ion batteries to catch fire. These batteries can explode and burn at very high temperatures. While not every EV submerged by the surge caught fire, the phenomenon has occurred often enough that insurers, automakers, fire officials, and politicians issued warnings to EV owners before Hurricane Milton hit.
Florida’s chief financial officer and state fire marshal, Jimmy Patronis, released a statement ahead of the hurricane, highlighting a series of fires following Hurricane Helene, which had already flooded much of the Gulf Coast weeks earlier. Authorities identified around 50,000 EV and hybrid registrations in the path of Hurricane Milton’s storm surge and reported at least 64 lithium battery fires after Helene, with electric vehicles responsible for 17 of those incidents. Other devices, including scooters, hoverboards, and golf carts, were also involved, and one fire was ignited by an electric wheelchair.
Geico, a prominent auto insurer in Florida, notified its policyholders of the potential dangers of electric vehicles, referencing Patronis’ statement and advising them to seek safe parking areas. Tesla also alerted its owners, urging them to relocate their vehicles to higher ground. Tesla cautions that EV owners should avoid submerging their vehicles, and if they do, they should maintain a distance of at least 50 feet from buildings until a mechanic can inspect it. In some cases, mechanics may be able to remove and dry out the battery of water-damaged EVs.
Electric vehicles pose a risk in homes affected by saltwater flooding. Patronis described flooded lithium-ion batteries as “ticking time bombs” that may cause even greater damage than the storms. Numerous incidents of EV fires have been shared on social media. A recent viral surveillance video from Pinellas County, Florida, shows a Tesla engulfed in flames after being flooded by Helene’s storm surge, filling a garage with smoke in under a minute.
The first recorded EV fire occurred in October 2012 after Hurricane Sandy. As electric vehicle ownership rises, battery fires have become more common. The National Highway Traffic Safety Administration (NHTSA) reported that during Hurricane Ian in 2022, 3,000 to 5,000 electric vehicles were affected, with 600 declared total losses and 36 catching fire. In some cases, fires ignited while the damaged EVs were being towed. An NHTSA 2021 report noted, “A thermal incident following vehicle immersion is significant and can actually create a dangerous situation not only for vehicle operators, but also for the first and secondary responders attending to the scene after the flood waters have receded.”
Saltwater conducts electricity, and if it penetrates the lithium-ion batteries in electric vehicles and other devices, it can cause short circuits, generating heat and potentially igniting a fire. This is similar to creating sparks by touching both terminals of a car battery with a metal tool. Although EV batteries are designed to be waterproof, seals can degrade over time, and saltwater is particularly corrosive. Flooding can instigate a series of short circuits known as “thermal runaway” within the battery’s internal cells, making the resulting fire difficult to control. Conventional firefighting methods, such as thermal blankets, may be ineffective, and because the battery is encased in steel, it takes time for it to cool down. Lithium-ion batteries produce their own oxygen and heat while burning, meaning they do not rely on atmospheric oxygen.
Lithium-ion battery packs consist of numerous cells within a compartment, containing a flammable liquid electrolyte. According to CBS News Innovation Lab, EVs and plug-in hybrids contain about 1,000 times more cells than an e-bike, which increases the risk of failure. It is not uncommon for a battery fire to appear to “reignite” after being extinguished, as flames can spread from one cell to another.
The NHTSA indicates that battery fires can occur weeks after electric vehicles have been submerged in saltwater, and extinguishing such fires can take several hours and between 3,000 to 8,000 gallons of water. After Hurricane Ian, an electric vehicle in Collier County reignited after a firetruck exhausted its water supply in just 10 minutes. Firefighters continued to hose down the vehicle for another hour before it reignited later that evening. Data from the U.S. National Transportation Safety Board reveals there are roughly 25 fires for every 100,000 electric vehicles sold, though certain regions may experience a higher frequency of fires after storm surges.
Conclusion
Florida has recently had storm surges from Hurricanes Helene and Milton that have caused concern regarding lithium-ion battery fires in electric vehicles. Insurers, car makers, fire officials, and politicians had all warned EV owners to keep electric vehicles away from homes during the storm, where worse damage could be caused by the vehicle combusting and bursting into flames. EV fires are much harder to put out than normal fires and require enormous amounts of water. Frequently, the vehicle is allowed to burn out as long as it is away from other structures. EV battery fires can happen weeks after an electric car is submerged in salt water, so Tesla suggests that the vehicle be checked by a mechanic before use.
