During the 2023 Hurricane Season, we all remember a few previous news reports of electric vehicles (EVs) catching fire before that; however, these news reports were related to flooding during a hurricane. In late September 2024, Florida Governor Ron DeSantis warned of EV fires prior to Hurricane Helene (1). He noted instances during Hurricane Ian in 2022 when a home survived the hurricane, but an EV parked in the garage caught fire and burned down the house. 

Unfortunately, after Hurricane Helene struck the Tampa Bay area, Governor DeSantis’ warning became a harsh reality. Many homes near the Gulf of Mexico or Tampa Bay experienced 4-5 feet of saltwater flooding. EVs parked in those areas experienced the same saltwater flooding. Residents of the Tampa Bay area began to see reports and videos of several house fires due to flooded EVs. In one incident, the Pinellas County Government released a video from a home security camera showing an EV burst into flames and engulf the garage within minutes. (2) 

In parallel with the EV fires, warnings circulated about turning on the power after houses had been flooded by saltwater. A local ABC affiliate reported 11 house fires were linked to saltwater corrosion and local fire officials urged homeowners to have an electrical inspection conducted prior to re-powering a flooded house. (3) In this article, we will explore what causes the fires, identify the common denominator, and discuss precautions for homeowners and restorers.

 

Understanding the Causes of Saltwater-Related Fires

The issue may be much worse than locally reported. Statistics from Hurricane Ian in 2022 indicate as many as 5,000 EVs with damaged batteries and 36 catching fire (4). The heart of the matter is saltwater. Saltwater contains sodium and chloride, which are up to 50 times more conductive to an electrical current (5). With batteries submerged in standing water, you have a recipe for a battery short circuit. The saltwater penetrates the battery and bridges gaps between the battery cells. The battery begins to heat up from the short circuit and a chain reaction occurs, which is called a thermal runaway. (4) Remember that the Lithium-Ion batteries in EVs have tremendous amounts of stored electrical power typically controlled by advanced circuits—until cells begin to short circuit. This doesn’t always happen immediately; sometimes it is days later. One notable situation repeated days after the hurricanes is an EV being loaded onto a flatbed truck and catching fire during transport.

 

Risks in Saltwater-Flooded Homes

Now let’s switch gears to saltwater-flooded homes. Picture a homeowner or restorer removing wet building materials and drying the home. What remains in items like electrical outlets? The same sodium and chloride that penetrated the EV battery cells! In this case, the saltwater corrodes the home’s electrical components like wires, screws, and switches. The corrosion starts the same short circuit the EVs experience, resulting in overheating and fires. (3)

In both scenarios, these principles are at work:

  • Saltwater deposits: The residual sodium and chloride left behind after flooding acts as a conductor for electrical currents, causing short circuits.
  • Massive electrical power: In EVs, the battery’s stored power intensifies the short circuit’s impact, while in buildings, any remaining electrical charge can cause heating and ignition.

 

Prevalence of Saltwater Flooding, Development, and EVs

It appears that the increasing frequency of storms along the Atlantic and Gulf coasts, continued coastal development, and increased EV ownership, have ultimately created a higher risk of saltwater-related fires. Coastal areas that rarely saw EVs two decades ago now have high concentrations of electric vehicles, as well as densely populated neighborhoods. A Tampa firefighter reported to the authors handling a dozen EV-related fires within days of Hurricane Milton, with some homes burning down due to limited accessibility caused by flooded roads and downed power lines. In some cases, firefighters simply couldn’t get to these fires due to the high risks they experienced in the aftermath of a hurricane.

 

Precautions for Owners and Restoration Professionals

EV owners and homeowners should consider the following steps to mitigate these risks:

  • EV Preparation: 
    • EV owners should move their vehicles to higher ground ahead of potential flooding. Remember that recent saltwater surges in Florida exceeded previous records; think along the lines of moving the vehicle to areas that are 20 feet or higher above expected flood water level. The inconvenience of relocating the vehicle will pay off afterwards!
  • Home Preparation: 
    • Homeowners should consider shutting off their main power prior to saltwater entering electrical outlets and panels. (4) 
    • If you plan to evacuate prior to the storm/flood event, consider the impact of shutting off power prior to leaving (security alarms, refrigerators, freezers, etc.). 
    • Better yet, consult with a licensed electrical contractor in advance and to determine how you will protect circuits/outlets and devise options to minimize flooding impact. 
  • Professional Help after a Saltwater Flood: Consult experts before repowering. 
    • For EVs, contact a dealership or tow company for guidance before moving or turning on the vehicle. 
    • For homes, engage a licensed electrician to ensure safe repowering. If some circuits have not been submerged, it may be possible to power them to support specific devices/lights/appliances.
  • Restoration after a Saltwater Flood: 
    • Restoration professionals should quickly apply lockout/tagout to control the repower process and keep impacted circuits/outlets isolated. 
    • Then proceed with extraction and drying. 
    • Use of a generator to power your equipment will likely be necessary. 
    • Enlist licensed electricians for a full inspection before restoring power.

 

Summary

Saltwater flooding presents significant risks for both EVs and buildings. The unique properties of saltwater amplify the likelihood of electrical short circuits, leading to fires that can devastate homes and neighborhoods. By understanding these risks, taking proactive steps, and consulting professionals, both homeowners and restorers can work together and protect lives and property in the aftermath of a coastal water surge and hurricanes.

 

References

  1. https://floridapolitics.com/archives/697953-gov-desantis-warns-electric-vehicle-owners-to-keep-them-dry-from-seawater/
  2. https://www.wtsp.com/article/news/local/pinellascounty/tesla-catches-fire-garage-floods-hurricane-helene-pinellas-county/67-8f16fb18-d7c3-4133-921c-009c44ebbba4
  3. https://www.abcactionnews.com/news/region-pasco/preventing-fires-after-the-flood-as-power-is-restored-pasco-county
  4. https://apnews.com/article/hurricane-helene-electric-vehicles-fire-flooding-0284e2eb2accc0570361def4e963eda0
  5. https://atlas-scientific.com/blog/water-conductivity-range/?srsltid=AfmBOooCnrrhoJ0KBQPfOrbC9xU-mwVEqZ_Clvr_-MfT94lKVt44DHqJ