Water is the best way to put out a lithium-ion battery fire. This surprises many people because pure lithium metal reacts violently with water, but lithium-ion batteries don’t contain pure lithium metal. They use lithium salt electrolytes, which are non-reactive with water. The National Fire Protection Association confirms that water works as an effective extinguishing agent for these fires.
That said, lithium-ion battery fires behave differently from ordinary fires, and the approach you take depends on the size of the battery and whether you can safely intervene at all.
Why These Fires Are Different
A lithium-ion battery fire starts with a process called thermal runaway. When a battery cell is damaged, overcharged, or exposed to extreme heat, it enters a chain reaction: internal components begin decomposing, which generates heat, which triggers more decomposition, which generates more heat. This loop accelerates rapidly and can cause the battery to vent hot gas, catch fire, or in some cases rupture violently.
What makes thermal runaway particularly dangerous is that it can spread from one cell to the next inside a battery pack. Even after flames appear to be out, remaining cells can reignite minutes or even hours later. This is the single most important thing to understand about lithium-ion battery fires: they can restart after you think they’re extinguished.
Small Devices: Phones, Laptops, and Power Tools
For a small battery fire in something like a phone, tablet, laptop, or power tool, douse it with water. Use plenty of it. If you have access to a sink, bathtub, or garden hose, sustained water flow is ideal because it both suppresses the flames and cools the battery cells below the temperature that sustains thermal runaway. Cooling is just as important as putting out the visible fire.
If you don’t have water immediately available, a standard ABC fire extinguisher can knock down the flames, but it won’t cool the battery enough to prevent reignition. You’ll still need water afterward. Do not try to smother a lithium-ion battery fire with a blanket or sand alone. The battery generates its own oxygen through chemical decomposition, so cutting off airflow from outside doesn’t reliably stop it.
Once the fire is out, don’t pick up the device. Leave it where it is (or move it outside with a non-conductive tool like a wooden broom handle if it’s safe to do so) and monitor it for at least an hour. Reignition is common.
Larger Batteries: E-Bikes, Scooters, and EVs
Larger battery packs contain far more energy and present a significantly greater risk. E-bike and electric scooter battery fires can produce intense flames that fill a room within seconds. If a large lithium-ion battery pack is actively burning indoors, your priority is getting everyone out rather than fighting the fire yourself.
Electric vehicle battery fires are an extreme case. They can require thousands of gallons of water to fully extinguish because fire departments need to cool dozens or hundreds of individual cells. These fires have been known to reignite hours or even days later. This is not something you can handle on your own.
Toxic Fumes Are the Hidden Danger
The flames are only part of the problem. Burning lithium-ion batteries release a cocktail of toxic gases that pose serious health risks even with brief exposure. These include carbon monoxide, carbon dioxide, and, most concerning, hydrogen fluoride. The fluorine compounds in the battery’s electrolyte and internal components convert to hydrogen fluoride gas at high temperatures.
Hydrogen fluoride is exceptionally dangerous. It can be absorbed through your lungs, skin, and eyes. Inhaling it causes irritation and burns to the nose and throat at low concentrations. At higher concentrations, it can trigger throat swelling, fluid buildup in the lungs, and lung collapse. The gas can also pass through your skin without immediate pain and cause deep tissue damage that doesn’t become apparent for up to 24 hours. Eye exposure can cause corneal damage ranging from temporary clouding to permanent scarring.
The immediately dangerous concentration for hydrogen fluoride is just 30 parts per million. In an enclosed room with a burning battery, that threshold can be reached quickly. This is why ventilation matters enormously. If you’re dealing with a battery fire indoors, open windows and doors to create airflow, and stay upwind or upstream of the smoke. If the fire is producing heavy smoke in a closed space, leave the area and call the fire department.
How to Reduce the Risk of Reignition
After extinguishing a small battery fire, the safest approach is to submerge the entire device in a bucket or container of water and leave it there. This keeps the cells cool enough to prevent thermal runaway from restarting. If full submersion isn’t practical, continue applying water periodically and watch for any signs of swelling, hissing, or rising temperature.
Move the device outside if at all possible. Even a fully extinguished battery can off-gas toxic fumes for hours. Keeping it outdoors, away from anything flammable, gives you a safety margin if it reignites. Don’t place it in a trash can, in your car, or near your house. A concrete or gravel surface away from structures is ideal.
What Not to Do
- Don’t use only a dry chemical extinguisher and walk away. It will suppress flames temporarily but won’t cool the battery. Reignition is likely.
- Don’t try to remove a swelling or smoking battery from a device. Puncturing or flexing a compromised battery can trigger a more violent reaction.
- Don’t charge a battery that has been damaged, dropped, or exposed to water. Charging a compromised cell is one of the most common triggers for thermal runaway.
- Don’t stay in an enclosed space with battery fire smoke. The toxic gases released are dangerous at concentrations you can’t see or smell at first.
Catching It Before It Starts
Most lithium-ion battery fires give warning signs before flames appear. A battery that feels unusually hot during use or charging, one that has visibly swollen or deformed its casing, or one that produces a hissing sound or sweet chemical smell is already in the early stages of failure. If you notice any of these signs, stop using the device immediately, move it to a non-flammable surface away from anything that could catch fire, and do not attempt to charge it again.
Charging is the highest-risk period. Avoid charging devices on beds, couches, or other soft surfaces that trap heat and can ignite. Use only the charger that came with the device or one rated for its specific voltage and amperage. Off-brand or mismatched chargers are a frequent cause of overcharging failures, particularly with e-bikes and electric scooters, where third-party replacement batteries and chargers have been linked to a sharp increase in residential fires.