A lithium battery fire is not like a trash can or a grease fire. The pack makes its own heat inside the cells, and it can look out and light back up later. The first moves are about people and cooling, not about which letter is printed on the extinguisher on the wall.
Get people away from it. The smoke is toxic, so don't stand in it. Call 911 even if you think you've got it handled — packs can reignite minutes, hours, or longer after the flames die down.
Don't count on the ABC on the wall to finish the job. An ABC can knock down the flame and may suppress the fire, but it probably won't put it out, because it doesn't cool the cells inside. Fire departments put a lot of water on these for the same reason: cooling. If you can cool the pack from a safe distance while help is on the way, do that from as far back as you can, and only to cool it. Don't walk away once the flames are gone.
For battery areas, F-500 is the best option in the industry and the best bet to fight a battery fire. It's a water additive made for lithium-ion battery fires, and it's what we point people to. Lithium batteries are still new, though, and there hasn't been any UL testing yet confirming which extinguisher is the right one for a battery fire. An F-500 is not a substitute for getting people out and calling 911.
We sell, install, inspect and service F-500 extinguishers. Call 1-800-348-9604 when you want one on the wall by the chargers.
Below is what's going on inside a pack, why cooling matters, where batteries show up in a building, and what to install before anything starts.
What's going on inside a pack
A lithium-ion battery is a bunch of cells packed together. Inside each cell, a thin separator keeps the positive and negative sides apart.
When a cell gets crushed, punctured, overcharged, or overheated, that separator can fail. Sometimes it's just a bad cell from the factory. Either way, the cell shorts inside itself and heats up fast.
That heat breaks down the electrolyte, the liquid inside the cell. It turns into hot gas that's flammable and toxic. The cell swells, vents, and can catch fire. The heat spreads to the cell next to it, and that one goes too. That chain is thermal runaway.
Here's the part that matters for you. The reaction makes its own heat. Covering it or smothering it doesn't stop what's happening inside the cells. A pack can look out and flare back up minutes or hours later.
Why the ABC on your wall won't cut it
An ABC extinguisher throws dry chemical powder. It's good at knocking flames down. On a battery, it can knock down the flame and may suppress the fire, but it probably won't put it out, because it doesn't cool the cells inside.
The powder coats the case, and the cells under it keep heating. So you get a pack that looks out, then lights back up. There aren't any peer-reviewed studies yet on what suppresses a lithium battery fire, so we don't claim a rating for any extinguisher on one.
Keep your ABC. It's still what you want for the cardboard, the bench, and the wall behind the charger. Just don't count on it for the battery itself.
Why cooling matters most
Fire departments put a lot of water on battery fires, and cooling is the reason. Water pulls heat out of the cells and slows the spread from one cell to the next.
F-500 extinguishers are water-based. The agent is mixed into the water to help it soak in and pull heat out faster. F-500 is a water additive made for lithium-ion fires, and water cools. That's why it goes by the chargers instead of another powder unit.
Don't count on any handheld extinguisher to stop a burning pack, big or small. A scooter, an e-bike, or a forklift battery holds a lot of energy, and any pack that catches is a 911 call.
We stock and sell F-500 extinguishers, and we inspect and service them.
If a pack starts smoking
Get people away from it. The smoke is toxic. Don't stand in it.
Call 911, even if you think you've got it handled, because it can come back.
If it's small, and you can move it outside without getting into the smoke, use a shovel or tongs. Set it on concrete or dirt, away from the building. If you can't do that safely, leave it and get out.
If you put water on it, do it from as far back as you can, and only to cool it while the fire department is on the way.
Don't walk away once the flames are gone. NFPA says a damaged lithium-ion battery can reignite hours, days, or even weeks later.
Where the batteries are in your building
Tool battery chargers. Shops charge packs on a bench, a lot of times right next to rags, cardboard, and solvent. Give the chargers their own spot on a metal shelf or bench, clear of anything that burns.
E-bikes and scooters. People bring them into break rooms, hallways, and apartments and plug them in by the door. That's usually the exit, so if a pack goes, the fire ends up between people and the way out. Charge them away from exits.
Forklifts and fleet equipment. Lithium forklift packs and electric fleet vehicles hold a lot of energy in one place. Charge them in one area, keep that area clear, and make sure everybody knows who calls 911.
Mining equipment. A lot of mines and fleets run diesel and electric machines side by side. On a diesel machine, the ABC is still the right extinguisher for a lot of what can burn on the iron, like fuel, hydraulic fluid, and ordinary combustibles. A battery pack on an electric machine is a different problem. We haven't seen any studies or completed tests yet that show which extinguisher or agent puts out a lithium-ion battery fire, so we won't tell you one does. Keep the ABC on the machine for the fires it can fight. If a pack catches, get the operator off the machine and get everybody away from it.
For all of them: use the charger that came with the battery. Pull swollen, cracked, or damaged packs out of service. Don't leave a pile of packs charging overnight with nobody around. And pick one spot outside where a bad pack can go.
Electric vehicles (EVs)
An electric vehicle battery is the biggest lithium pack most people will ever be around. If a car, a truck or a fleet vehicle with one of these packs catches, get everybody away from it and call 911. Don't stand there and fight it with a handheld extinguisher.
A pack that size can keep burning, and it can reignite after it looks like it's out. An ABC extinguisher may knock the flames down, but it isn't the finish, because it doesn't cool the cells inside. Lithium isn't one of the letter classes on an extinguisher label, either, so there's no class to shop for that covers it.
For the area around chargers, F-500 is the extinguisher we point people to. If you've got workplace chargers, or fleet vehicles charging inside a building, we'll walk the site with you and talk through what to install near the chargers and how people get out.
What to install near the chargers
On a walk-through, here's what we'd usually tell you.
Keep ABC extinguishers for the room, same as always, for the cardboard, the bench, and anything else around the chargers that can burn. Keep a clear path out, with nothing parked in it.
Put an F-500 near the charging area, on the way out — not right on top of the charger. You don't want to be reaching over a smoking pack to grab it.
If it's a whole room full of chargers, or equipment that sits unattended, what matters most is where it charges, what's around it, and how people get out. We'll walk it with you.
Whatever you install needs to be looked at every month and inspected and serviced like any other extinguisher. We keep the due dates. You don't have to think about them.
For how lithium fits against the letter classes, see classes of fires.
Questions people ask
- How do you put out a lithium battery fire?
- Get people away, call 911, and cool the pack from a safe distance if you can. Don't count on a wall ABC to finish it. F-500 is the best bet we point people to for battery areas, but it isn't a substitute for 911. Packs can reignite after the flames are gone.
- What class of fire is a lithium battery?
- It isn't one of the letter classes on the extinguisher. Treat a lithium pack as its own problem.
- Can you use water on a lithium battery fire?
- Water is what fire departments use to cool a battery fire, and it takes a lot of it. It may not stop the fire, so get people out and call 911 first.
- Do I need a lithium extinguisher at home for my e-bike?
- It's not a bad idea, and F-500 is the one we'd point you to. What matters more is how you charge it. Use the charger it came with, keep it away from the door, and don't charge it overnight while everybody's asleep. If it catches, get out and call 911.
- Does an F-500 need the same service as my other extinguishers?
- Yes. It's an extinguisher on your wall. It gets looked at every month and inspected and serviced on schedule.
Tell us where the batteries are
Call 1-800-348-9604. Tell us where the batteries are and how they get charged. We'll walk it and tell you what to install. We sell, install, inspect, and service extinguishers, including F-500.