Firefighters Love Fighting Fires… Except EV Fires
For a profession filled with individuals who enjoy running toward the plumes of smoke everyone else is running away from, you’d assume firefighters would love EV fires.
Nope. Can’t stand EV fires.
Here’s a funny conversation where someone asks a group of firefighters:
“Would you rather fight 11 gasoline car fires or 1 EV fire?”
Some choice responses:
- “11 gas fires 100%.”
- “Anything that can burn while fully submerged in water terrifies me.” (Uh, fair. Me too.)
- “11 fires > 1 fire. Goin’ to Job-Town*, brütherz.”
*Jobtown is where you’re headed to do what you’re paid to do (or, if you’re a volunteer like I was, what you’re not paid to do). Jobtown is where fires happen.
[ Credit: Fire Department Coffee]
And one last opinion to hammer it home…
“11 car fires, no doubt. It would take less time. Less danger from exotic gasses. The fire is less energetic and water will actually put it out.”
That last one really drives home the point… let’s dive in there.
Here’s Why Firefighters Hate EV Fires
Let’s break down how the EV fire is different from a gas-powered car fire, and that’ll make it pretty obvious why firefighters hate dealing with them.
Gasoline fires are less energetic.
So, you can fight a gasoline fire with just the water in the rig. It’ll be over before you need to plug into a hydrant, most of the time. Honestly, motorists like you or me have a decent shot of putting it out with a handheld extinguisher.
A note for my chemists in the audience: a burning EV and a burning ICE car release similar amounts of energy as heat, both in total and at any given moment. So you might think, EV fires are not more energetic. “Energetic” is also a trade term among firefighters, that just means the fire is harder to put down, so bear with me as I mix metaphors here.
EV Fires Take Forever.
Fighting fires is fun. Fighting fires for hours on end, it starts to lose its appeal. Your typical gas-powered car on fire? Put the hose on it for 10 minutes, you’re good. They hardly ever reignite, either. More on that thoroughly joyous topic in a minute. EV fires can take 60+ minutes, they reignite, and you’re wearing a mask and full bunker gear that whole time.
New and Exciting Toxic Gasses.
Speaking of that mask… EV fires put off all the usual gasses a fire puts off, and then some. Most common battery chemistry for EVs is lithium-ion. Those batteries off-gas hydrogen fluoride, among other things. HFL is bad news on its own, inhaling it kills you.
Just Add Water, and You Get Powerful Acids.
Hydrogen fluoride plus water? Well, that’s when the real show starts. That’s how you make like Walter White and create hydrofluoric acid. FUN!
You’ll fight these fires buttoned up tight, and you’ll decontaminate all your equipment when you’re done, to make sure powerful acid isn’t burning into you or your gear.
Did I mention, don’t breath that stuff? Your lungs are wet, and remember, it creates powerful acid when mixed with water. You’ll have a bad time.
Oh Right, and EV Fires Shoot Projectiles
Did I mention… if you show up late, and the battery has gotten deep into its “thermal runaway” stage, it shoots projectiles at you?
Yes, keep your helmet on, because EV fires shoot back. The projectiles are individual battery cells, cooking off and shooting off like molten metal rockets. It’s like when the gas-tank on a gasoline vehicle cooks off, but less predictable and more toxic.
Now, mentioning gas tanks, you might think: that’s an advantage! At least they don’t explode, you know, like a bomb explodes. Haha, about that. Hydrogen fluoride is one off-gassing byproduct of lithium-ion batteries as they overheat. Straight hydrogen gas is another. Yes, hydrogen like the Hindenburg had. That vapor cloud can explode, and it can also shoot directional jets of flame, as a treat.
That’s Just Lithium Ion Batteries… Other Batteries Work Totally Different
The wild part? Lithium-ion batteries are the most common battery chemistry, but not the only option. If somebody’s wacky no-brand electric bicycle or some new-fangled car model catches fire, god only knows what the battery chemistry is. Will it create acid gas when you hose it down? Are we talking red dragon breath or green dragon breath when we put water on this thing? Only one way to find out. That uncertainly really gnaws at you. Now, automotive manufacturers create fact sheets for first responders, but they’re not super helpful, in part because you’re in a rush once you arrive on-site and pulling up a bunch of PDFs isn’t high on the officer’s list of things to do.
Anyhow, I bet you’re seeing how going to this particular neighborhood of Jobtown isn’t the most fun on the block. In a nutshell, firefighters hate EV fires because they’re dangerous, hard-to-predict, and take forever to get control of.
Editor’s note: Originally, I had like 500 words written on how much firefighters love fighting non-EV fires, and I realized that wouldn’t be interesting to most readers. If you’re weird like me and that IS interesting to you, this thread summarizes it pretty well and the folks over at Fire Department Chronicles even made a music video about it.
(If y’all don’t know them, they run Fire Department Coffee. Great org, funny as all get out, throw them a friendly word and subscribe if you like, and buy their coffee if you see it.)
One More Thing for the Road… Reignition
Just like an EV that burned four days ago, I had completely forgotten about another hot topic… reignition.
The Australian team who runs EV Firesafe offers case studies that are worth a look:
- Case one: A wrecked EV burns, and then burned again 4 times in 48 hours. Call it Rasputin, that fire just won’t die!
- Case two: A car burned in a house fire from another source, but was extinguished. 68 days later, it burned again at the repair shop.
- Case three: A car wrecked but did not burn. At the salvage yard 4 days later, it ignited. This is called “delayed ignition.”
It’s bad enough that heavily staffed (read: big city) fire departments will sometimes dispatch a unit to follow the flatbed that takes the burned EV to the junk yard, just in case it reignites.
That’s my final word on that. But I might check back in 48 hours… As an aside, we’re big fans of EVs here at FuelArc News. Our goal here is to be realistic about the unique risks to the new technology, and to highlight how emergency services are training to fight those risks.
Check out our article on the videogame being used to train firefighters to fight EV fires next!
