When a hurricane like Helene or Milton devastates coastal communities, already strained first responders face a new, and growing, threat: the lithium-ion batteries that power electric vehicles, e-bikes and countless gadgets. When exposed to the saltwater of a storm surge, they risk bursting into flames — and taking an entire house with it.
“Anything that’s lithium ion and exposed to salt water can have a problem,” said Bill Morelli, the fire chief in Seminole, Florida, and the bigger the battery, the bigger the threat. This is what makes EVs especially dangerous. “[The problem] have expanded as they continue to become more and more popular.”
It is not yet clear how many vehicles caught fire in the aftermath Hurricane Miltonwhich struck Tampa Bay on Wednesday, leaving at least 13 people dead and about 80,000 in shelters. But there was 48 confirmed battery fires related to storm surge of Hurricane Helene11 of them associated with EVs.
Morelli’s teams fought three of them. St. Petersburg Fire Rescue reported at least two, one from a electric bike and another of a Mercedes-Benz EQB300 that resulted in what a fire department representative called “extensive damage to the home.” CNN and other outlets have reported on a fire in Sarasota that was started by a Tesla Model X.
In general, such fires are far from common. Idaho National Laboratory found that of the 3,000 to 5,000 electric vehicles damaged by Hurricane Ian in 2022, approximately three dozen set on fire. Public awareness of the risk has since grown, with officials up to and including Florida Governor Ron DeSantis urging residents to move their EVs to higher ground ahead of storms. But the chemistry and construction of lithium-ion batteries make them particularly susceptible to fires that are difficult for first responders to fight.
“They burn hot, they burn fast, and they’re hard to put out,” Morelli said.
The battery in an EV consists of thousands of cells stacked and packaged in a sealed casing. If salt water, which is particularly conductive, reaches the inside of a battery, it can cause a short circuit, which can generate excessive heat that jumps from cell to cell. “It’s called ‘thermal runaway,'” says Andrew Klock, senior manager of education and development at the National Fire Protection Association.
As a battery heats up, it releases flammable gases that can ignite. Once the car catches fire, traditional methods of extinguishing vehicle fires – such as foam or thermal blankets to smother the flames – are not as effective. “Lithium-ion batteries generate their own oxygen and heat when they’re on fire,” Klock said. “You can’t starve the fire.”
Instead, first responders should direct high volumes of water as directly as possible to the battery pack to reduce the heat. The International Association of Fire Chiefs recommends having 3,000 to 8,000 gallons on hand—which can be difficult during a disaster, when hydrants may not be working properly and trucks have a limited supply on board.
“They take tons and tons and tons and tons of water to put out,” said Morelli, who is working with other departments to procure more thermal blankets. A ready supply of them can enable firefighters to smother the flames enough to move the car away from structures so it can burn itself out safely.
Klock said “training is extremely important” to effectively fight these fires. But of the roughly 1.2 million firefighters in the country, only about 350,000 have completed the association’s training, he said. “There is a lot of work to do.”
Nor does the danger end when a storm passes. According to the Department of Transport“the time frame in which a damaged battery can ignite varies, from days to weeks,” which is one reason Tesla urges owners not to operate their vehicle until a dealer inspects it.
The Alliance for Automotive Innovation, which represents 44 car manufacturers and suppliers, declined to comment but has a letter it sent to Republican Senator Rick Scott of Florida on the issue in 2022. It notes that “safety is a top priority for our members, which is why they are engaged in long-term efforts to address fire risks for both conventional fuel vehicles and EVs.”
Meanwhile, a series of efforts are underway to try to prevent these fires from starting. The Federal Emergency Management Agency has research on emerging dangers of battery storage systems at home. Other researchers are looking at how to make batteries safer, including Yang Yang, an associate professor of materials science and engineering at the University of Central Florida. His team develop a battery which, instead of fighting salt water, uses it as the main electrolyte.
“It can be soaked in the salt water and still work well,” said Yang, who began working on the project after living in Houston and Florida and seeing firsthand the problem floods present. While he said that car companies have yet to contact him about his research, he is optimistic that safer batteries could be on the market within the next few years.
Until then, storms like Helene and Milton may be among the biggest drivers of public attention to both the problem and prevention methods. Yang, for example, finds that possibility bittersweet at best: “I don’t want people to have any problems with their electric vehicles.”
