Vape Explosions: What Causes Fires and Other Accidents?

There was a time when e-cigarette explosions and fires ruled the news. In fact, during the period just before anti-vaping groups settled on JUUL and the youth vaping epidemic as their primary focus, vaping explosions were featured almost daily in news stories. They remained a regular feature until they were overshadowed by the 2019 outbreak of black market THC vaping-related lung injuries.

To those whose vaping knowledge is based solely on alarming news stories, e-cigarette thermal events like fires and explosions may seem like common occurrences, but they are actually very rare. They happen when a battery overheats and the chemicals and gasses escape the battery rapidly.

Most people are unaware that the vast majority of popular vape mods, pens, and pods have circuitry to regulate the output power and protect users from dangerous battery malfunctions. Among commercial vape devices, only unregulated mechanical mods pose a serious risk for accidents to inexperienced users.

Security camera footage from vape battery accidents can be confusing for people with limited knowledge of vaping products. The viewer sees a huge flash and the vaper’s clothes catching on fire, and assumes a vaping device has spontaneously exploded. It’s rare that an expert is interviewed to explain what actually happened.

In reality, most vaping electrical accidents are actually spare battery accidents—not equipment failures—and they’re usually caused by user error. Generally speaking, vapers who follow basic principles of battery safety are at low risk for e-cigarette fires or explosions.

Aside from very rare defective batteries, most vaping battery thermal events and fires are caused by a few specific issues, all of which are easily avoidable.

Because vaping skeptics want to believe the worst about vaping—and nothing makes that easier than seeing a vaper with their pants literally on fire—they dismiss the facts about battery accidents as the convenient excuses of vaping evangelists.

What causes vaping explosions and fires?
The most common causes of vaping battery accidents can be grouped together as user error. In fact, most “e-cigarette explosions” don’t even involve an e-cig.

Loose batteries carried in pockets or purses
A large majority of “vaping explosions” are in reality caused by loose batteries carried in pants pockets, not by vaping devices at all. FDA Center for Tobacco Products researchers found that 77.3 percent of burns caused by vaping accidents were to the upper leg and lower trunk—the location of the hip pocket.
When you press the fire button on a vape device, it connects the circuit between the battery’s positive and negative poles, and power flows to the device. That’s how all modern portable electronic devices—like cell phones and electric toothbrushes—are powered, and like those products, regulated vaping devices have redundant safety circuitry that prevents batteries from overheating or exploding if they malfunction.

Unfortunately, vapers’ pockets have no short-circuit protection. If you carry an extra battery for your mod in a pocket with keys or loose change, those metal objects can accidentally connect the positive and negative poles of the battery. When power flows directly from the positive to the negative pole—instead of into a regulated power circuit—the energy loops back into the battery, and it can instantly overheat and catch fire or explode.

Loose batteries should never be kept anywhere they can come into contact with metal objects. Simple plastic cases and silicone sleeves are available to prevent such accidents. They’re inexpensive, and many vape battery sellers even include them free with battery purchases. Every vape battery sale should include a warning from the seller and a protective case.

The issue of vape battery thermal events and fires may disappear in the future. New battery formulas are being developed that replace the flammable liquid electrolyte in lithium batteries with stable solid-state electrolyte made from glass. Other researchers have developed battery designs with a fire-resistant barrier between the positive and negative poles of the battery.

Mislabeled batteries and low-resistance coils
There is a limit to the amperage a device can draw from a battery, and those numbers may be exaggerated by battery manufacturers, wholesalers or distributors. Sometimes batteries are marked “30 amp,” for example, when the battery is only capable of handling 30 amps for a few seconds, rather than for continuous use. All batteries have a pulse, or peak, rating—but that should never be printed on the wrapper. The battery manufacturer should mark the battery with the rating for continuous use.

This matters for vapers who are building low-resistance coils for use in some unregulated mods that have no safety features. If an atomizer draws more current than a battery can safely provide, and there is no electronic cutoff in the device, the battery can overheat and go into thermal runaway. That can cause a fire, or—if the battery can’t easily vent the heat—an explosion. If you’re holding the device to your mouth when it explodes, the damage can be severe and life-threatening.

Such events are extremely rare, but they do happen. In 2018, a Florida man died when an exploding mechanical mod pierced his brain. A year later, a Texas vaper was killed after an explosion from a similar device severed an artery in his neck. Neither accident would have happened if the men had used regulated vape mods.

No vaper should attempt to use mech mods or build low-ohm coils until they understand Ohm’s Law and the interplay between electricity and resistance. Frankly, there are so many inexpensive, high-quality variable-wattage and temperature control devices available now, it’s hard to understand why anyone would even bother with mech mods anymore.

Counterfeit, low-quality, and damaged batteries
Batteries are mass-produced and tested in the factory. Those that don’t meet the standards for direct sale to electronics manufacturers are sometimes sold to resellers, who rewrap them with different brand names and sell them for other uses. The best vaping batteries are the highest-quality ones from the major battery manufacturers.

Almost all vape batteries are either lithium-ion (Li-ion) or lithium-polymer (LiPo) cells, which are generally safe. However, it is possible to get a lemon—especially if you buy cheap batteries, which are often rewrapped, low-quality cells.

Another issue is counterfeit batteries, which are low-quality or inappropriate cells rewrapped with high-quality brands’ labels. These are often very low-amp batteries that are wrapped to imitate well-known models (with higher amperage ratings) that people trust. Almost every popular battery on the market has been counterfeited.

To avoid rewrapped and counterfeit batteries, buy only from reputable battery dealers—never from eBay or sellers you’ve never heard of—and choose well-known brands with appropriate amp ratings and specs. Saving a few dollars by buying cheap batteries isn’t worth the risk.

Good 18650 batteries cost $6-12 each. The good news is that high-quality batteries hold a charge longer and take more charges during their lifetime than cut-rate batteries.

Another cause of shorted batteries is damaged battery wraps. The thin plastic cover that prevents the metal body of the battery (the “can”) from making contact with the sides of the device’s battery chamber can get torn. If that happens, you should either discard the battery, or have it rewrapped. Rewrapping the battery yourself is not difficult; you can purchase sleeves cheaply and do it in minutes.

Batteries that have been repeatedly dropped or are noticeably dented should also be replaced and recycled. The chambers that hold the chemicals inside the cell can be damaged and create a dangerous internal reaction. Batteries that have been submerged in water should also be replaced.

NOTE: most major battery manufacturers say their 18650 batteries are not intended for use in vaping devices or other electronic products that use single cells.

Charging problems and best practices
It is possible to accidentally overcharge batteries, especially if you use a charger meant for a different kind of battery. If you use a charger intended for large, high-capacity batteries to charge a small vape pen, for example, it can create instability in the battery cell.

A defective battery charger can also overcharge cells. The best vape battery chargers have overcharge protection that prevents charging beyond the highest capacity of the battery cells. Typical vape batteries, like 18650s, are intended to operate at 3.7 volts, but they are capable of being charged to 4.1 or 4.2 volts. Anything more and they can become unstable.

Most charging problems can be avoided by charging batteries only when you’re present in the same room. Don’t charge them overnight, or leave the house when they’re charging. If batteries ever get hot when charging, replace and recycle them.

Simple precautions = battery safety
Legal actions by victims of vape battery accidents against vape shops and battery manufacturers have become commonplace. Such actions are a reliable route to a modest payday for personal injury lawyers, because both shops and battery manufacturers have liability coverage with insurance carriers who settle almost every action. But rarely is an e-cig explosion or fire the fault of the seller or manufacturer. Nearly all are caused by user error.

In the future, there will be safer battery chemistries that eliminate the dangers. Until then, attention to battery safety practices can eliminate most accidents.