Are Hand Warmers Flammable: Can It Catch Fire?

Also known as warm pads, hand warmers can quickly heat cold hands and relax muscles and joints. While getting a disposable or rechargeable heating pad like Hot Hands, Grabber, or Zippo sounds fantastic, you may have a few concerns about their flammability.

In particular, are hand warmers flammable, can they catch fire, or explode?

This guide has everything you need to know about fire safety and hand-warming pads to keep you safe.

Are Hand Warmers Flammable?

Hand warmers are not flammable or dangerous when they are used correctly. But they can start a fire or cause an incident if punctured or kept near combustible material.

Can Hand Warmers Catch Fire?

Hand warmers cannot catch fire on their own; however, their components are flammable. Hand warmers produce heat, so if you keep them close to any combustible substances, such as fuel, they can cause a fire.

But what about exploding? Are hand warmers explosive?

Let’s dig a little deeper into the topic to better understand all the potential hazards of rechargeable and disposable hand warmers.

Are Hand Warmers Flammable

What Are Hand Warmers and Their Usual Materials?

Hand warmers are small tools that produce heat. This heat can quickly warm up cold hands and relax a stressed area. In general, there are three types of hand warmers. Each of them utilizes a different kind of mechanism and materials.

Let’s walk you through each version of hand warmer.

Air Activated Hand Warmers

These are single-use heat packets that provide warmth through an exothermic oxidation reaction. This process occurs when the packet’s iron powder gets exposed to the air. A popular brand is Hot Hands.


Air-activated hand warmers contain:

  • Iron powder (Highly flammable)
  • Salt (Not flammable)
  • Activated charcoal (Highly flammable)
  • Vermiculite (Non-flammable)
  • Cellulose (Flammable)

Here, salt catalyzes the oxidation process between iron and air. The activated charcoal holds water, which is necessary for the oxidation process. It also plays the role of spreading the heat evenly throughout the packet.

Like activated carbon, vermiculite also holds water. But it helps to diffuse the iron powder. Finally, the cellulose in the air-activated hand warmers acts like a filler material. As you might have guessed, these are single-use products.

Battery-Operated Hand Warmers

As the name suggests, these hand warmers come with a rechargeable battery. Usually, it’s lithium-ion. The battery sends power to the onboard electrically resistive heating system to produce heat.

Battery-Operated Hand Warmers

The system converts electrical energy to heat. Unlike air-activated hand warmers, battery-operated hand warmers are reusable. They also offer control over the heat intensity. The rechargeable battery of these devices is a highly flammable component.

Reusable Non-Battery-Operated Hand Warmers

There’s another version of hand warmers that do not need battery power to operate. And these do not use any iron. Instead, they come with a supersaturated sodium acetate solution, which is flammable.


These units work through an exothermic crystallization process. You can reset the process by boiling the crystalized sodium acetate.

Flammability and Catching Fire Risk of Hand Warmers

So, what is the fire risk of hand warmers? Are disposable hand warmers safe?

Well, they cannot catch fire on their own. But you cannot forget that hand warmers are only safe when you use them correctly.

As you know by now, combustible or flammable materials are inside each type of hand warmers, which can cause them to catch fire, and potentially explode, if not used as directed.

Let’s give an example to make you understand why caution is necessary while using them.

Back in November 2018, there was a fire incident in Lincoln County. According to the fire officials, a hand warmer was partly responsible for the fire. The vehicle that caught on fire was experiencing issues with the exhaust system. It was heating up, which started a small fire. The car owner kept a hand warmer on the floor of the car. For the heat, the hand warmer melted, intensifying the fire inside. In other words, as the hand warmer came in contact with a flammable combustible, it started a major fire incident.

That gives you an idea of how cautious you need to be when you have or are using a hand warmer.

Safety Precautions to Take When Using Hand Warmers

To keep yourself safe from a fire or explosion, you should consider a couple of precautionary measures while using hand warmers.

They are as follows:

Use Only as Directed

No matter what, you should tamper with the hand warmer. It does not matter which type you are using. The internal elements or components should be exposed. Read the instructions correctly and adhere to those only.

Don’t Place the Hand Warmer Directly on Your Skin

Non-battery-operated hand warmers can get extremely hot. In fact, the extreme heat from these units can cause burns when in direct contact with the skin.

Never Puncture the Hand Warmer

Whether it’s a battery-operated hand warmer or a disposable packet warming pad, you shouldn’t punch holes in it. Do not even keep it near any sharp objects. The puncture can cause the components or elements to create a fire.

Dispose Properly

To dispose of the hand warmer, check the manufacturer’s instructions. Make sure to dispose of it in a recycle bin if it’s a rechargeable unit.

Keep It Away from Flammable Materials

As discussed earlier, hand warmers can start a fire if you keep them near flammable material. Follow the manufacturer’s instructions when it comes to storing. And, keep it away from flammable or combustible materials when you are using it.

Frequently Asked Questions

1. Can hand warmers cause burns or skin damage?

Hand warmers can only cause skin damage or burns when you are using them with direct contact with your skin. Even if its heat intensity is controllable, you should consider using it on top of clothing.

2. Can Hot Hands Catch Fire or Explode?

Hot Hands hand warmers cannot catch fire or explode on their own. Hot Hands warming pads are designed with safety in mind and are not inherently flammable or dangerous when used as directed. 

3. Can zippo hand warmers start a fire?

Zippo hand warmers will not start a fire if you are following the safety guidelines correctly. Moreover, you should not let the fuel from the inside leak.

4. Can rechargeable hand warmers explode?

Rechargeable hand warmers will not explode if you do not puncture them or use them incorrectly. Make sure to strictly follow the charging and usage guidelines from the manufacturer.

Final Words

So, are hand warmers flammable? Can hand warmers catch fire or explode? As you discovered, hand warmers are 100% safe to use if you follow the manufacturer’s guidelines and practice proper safety measures.

On that note, if you use hand sanitizer on a regular basis, it’s a good idea to know the hand sanitizer flammability rating as well. That will help you dictate whether you can keep the hand warmer near a bottle of sanitizer or not.