Salt water poses fresh concerns over electric cars and fire
As of this writing, there’s no way to know whether the Tropical Depression 13 in the Atlantic will turn into Hurricane Lee, but meteorologists are certain it will happen.
“Given the mostly favorable environment for strengthening, the National Hurricane Center forecasts this system to become a hurricane by Thursday and a Category 3 or 4 hurricane by this weekend,” said the Weather Channel on Tuesday, September 5.
Hurricane Idalia, which struck North Florida two weeks ago, was a Category 3. Ian, which hit Southern Florida less than a year ago, was a Category 5.
If Lee does strike the U.S., no matter where, owners of electric cars who live near the coast should beware.
At least, that’s the message from Florida Chief Financial Officer and State Fire Marshall Jimmy Patronis. He wrote that on October 6, 2022, “I joined North Collier Fire Rescue to assess response activities related to Hurricane Ian and saw with my own eyes an EV continuously ignite, and continually reignite, as fire teams doused the vehicle with tens of thousands of gallons of water.
“Subsequently, I was informed by the fire department that the vehicle once again reignited when it was loaded onto the tow truck. Based on my conversations with area firefighters, this is not an isolated incident. As you can appreciate, I am very concerned that we may have a ticking time bomb on our hands.”
Exposure to salt water caused 21 electric vehicles to catch fire in 2022 with Hurricane Ian, and at least half a dozen due to Hurricane Idalia, which did not dump as much salt water on dry land in populated areas as Ian did. An early assessment, before all available data was in, said that of the first 16 reported electric car fires due to Ian, one was a Porsche, one was a Lucid, and 14 were Teslas, the latter of which is by far the most popular electric car brand.
So what’s really going on? Professor David Richardson, dean of the Colleges of Liberal Arts and Sciences at the University of Florida explains to Hagerty: “The electrical conductivity of sea water is, compared to other water, much more electrically conductive than distilled water, and it is generally far more conductive than fresh water. Seawater has less conductivity than copper wire, but it is still a great conductor.
“Imagine two electrical connectors with a large voltage across them. Connecting those together (shorting them) with wire results in a very large current flow that can set off a chain of undesirable effects, creating a lot of heat, sparks, etc. The same can happen with sea water.”
Presently the only fire suppression method available to fire departments is douse the battery (underneath the car) with, as Patronis mentioned, sometimes thousands of gallons of water. Even then, there’s no guarantee that the fire won’t reignite, due to “stranded energy” left inside the battery.
Fresh water doesn’t pose the same risk as salt water, even if the car is completely submerged.
On a per-incident basis, the fires are taking a massive amount of time for local departments that, no doubt, are seriously needed elsewhere for search and rescue. That seems to be the case if the electric car is parked outside, away from buildings. If inside a garage, the entire house would be compromised. EV owners may be wise to move their cars inland, if possible, in the event of a storm large enough to flood their property. Even moving the vehicle outside and away from buildings would minimize risk.
This is not to say that fully electric vehicles are more likely to catch fire separate from the salt water addition to the data, because they aren’t. A National Transportation Safety Board firefighter training video says there are 170,000 car fires a year, but only a small percentage involve electric vehicles. A Highway Loss Data Institute bulletin from April reported that among electric vehicles with a conventional ICE counterpart, observed non-crash fire claim frequencies were 26 percent lower for the electric variants. Among electric vehicles without conventional counterparts, results were identical for the Nissan Leaf compared to the Nissan Versa, which is similar in size and body style.
In fact, research by an insurance industry website, AutoinsuranceEZ.com, indicates that hybrid vehicles are actually the most fire-prone per 100,000 sales. Gas vehicles are second, and electric vehicles place third, with only 25 fires per 100,000 electric vehicle sales.
In any case, the salt water issue is pressing for those living in flood-prone and seaside regions.
After Ian, Patronis, the Florida State Fire Marshal, wrote to U.S. Transportation Secretary Pete Buttigieg, asking for a “more robust” response to battery fires due to salt water exposure that must be extinguished by local fire departments.
“When my office asked National Highway Traffic Safety Administration and Tesla officials on how long the risk of fire exists once a battery is compromised from saltwater and/or damage, no credible timetable exists, because the current situation has not been fully researched,” he wrote to Buttigieg.
“As the State Fire Marshal, I must ensure local fire teams have access to all the equipment needed for these operations, including Tender Strike Teams, Engine Strike Teams, Personal Protective Equipment and thermal imagery. Your response may be the difference between life and death.”