Saltwater flooding a serious fire threat for electric vehicles

Hurricanes cause billions in damage, including EV fires from flooded batteries; experts advise caution and safety measures.

Flooding from hurricanes Helene and Milton inflicted billions of dollars in damage across the Southeast U.S. in September and October 2024, pushing buildings off their foundations and undercutting roads and bridges. It also caused dozens of electric vehicles and other battery-powered objects, such as scooters and golf carts, to catch fire.

According to one tally, 11 electric cars and 48 lithium-ion batteries caught fire after exposure to salty floodwater from Helene. In some cases, these fires spread to homes.

When a lithium-ion battery pack bursts into flames, it releases toxic fumes, burns violently and is extremely hard to put out. Frequently, firefighters’ only option is to let it burn out by itself.

Particularly when these batteries are soaked in saltwater, they can become “ticking time bombs,” in the words of Florida State Fire Marshall Jimmy Patronis. That’s because the fire doesn’t always occur immediately when the battery is flooded. According to the National Highway Traffic Safety Administration, about 36 EVs flooded by Hurricane Ian in Florida in 2022 caught fire, including several that were being towed after the storm on flatbed trailers.

Many consumers are unaware of this risk, and lithium-ion batteries are widely used in EVs and hybrid cars, e-bikes and scooters, electric lawnmowers and cordless power tools.

I’m a mechanical engineer and am working to help solve battery safety issues for our increasingly electrified society. Here’s what all owners should know about water and the risk of battery fires.

The trigger for lithium-ion battery fires is a process called thermal runaway – a cascading sequence of heat-releasing reactions inside the battery cell.