Is Styrofoam Flammable? Here’s What You Need To Know

We've all used styrofoam, from your hot coffee's plastic cup to the padding for transporting fragile goods to insulation for construction and building.

Plus, some people use styrofoam plates for microwaving food but never ask the question – is styrofoam flammable? We will answer this question in detail, giving important tips for proper handling.

Is Styrofoam Flammable

Is Styrofoam Flammable?

The answer is no. Styrofoam is not flammable. A solid is considered flammable when it can cause a fire through friction or slight contact with naked fire. Some of these solids are self-reactive and can ignite at room temperature.

Styrofoam will ignite and burn with temperatures between 650–800 degrees Fahrenheit, so it's not flammable under normal conditions.

What Is Styrofoam?

Styrofoam is a lightweight polystyrene foam used to create disposable materials and insulators. It's often used in construction and comes in large, white blocks. Some companies still use it for packaging hot coffee and food because it keeps it warm inside while protecting your hands outside.

What Happens When Styrofoam Gets Too Hot?

Although styrofoam isn't flammable, it's still combustible. So here are a few things you need to know about it. Firstly, styrofoam is made from polystyrene – a petroleum-based product.

This hydrocarbon is solid at room temperature and burns to release a toxic gas called styrene that damages the nervous system with long-term exposure. Styrofoam remains intact at room temperature and temperatures up to 150 degrees Fahrenheit.

But will start to deform and melt at temperatures between 212–320 degrees Fahrenheit. Finally, it will spark and burn at temperatures over 690 degrees Fahrenheit.

Your microwave has no business getting this hot – however, your grills and ovens might. So although it has a better chance of melting, your styrofoam or polystyrene products won't burn under regular use.

How Flammable Is Styrofoam?

Flammable materials are considered fire hazards because they can start and spread fire quickly. However, styrofoam isn't as flammable as most people think. With most day-to-day uses, styrofoam products might only reach temperatures that cause deformation or melt.

The regular, everyday use of styrofoam products would rarely cause it to reach 600 degrees. However, when using styrofoam as an insulator or heat protector, it's important to note that styrofoam is still combustible. So think again if you're ever tempted to set your styrofoam food containers on fire for that cool Instagram shot!

How Flammable Is Styrofoam

How Often Can Styrofoam Catch Fire?

I was curious about this myself, so I did a little digging. Styrofoam can catch fire under the right conditions, but it's not as flammable as you might think.

While it's not flammable in the traditional sense, styrofoam can easily ignite and start burning if it comes into contact with an open flame. For this reason, it's important to be extra careful when cooking with it and ensure any candles or flames are well out of reach.

It needs a continuous heat source to ignite, and the flame won't spread quickly. In other words, you won't set your kitchen on fire by microwaving a styrofoam plate. But it will burn if exposed to an open flame or too much heat.

Why Does Styrofoam Burn So Fast?

When it eventually starts to burn, it does so very quickly because the material is made up of 90% air, and its cells are few, tiny, and widespread. When those cells are heated, they expand and release by-products. And when that happens, the styrofoam can quickly catch fire and keep burning.

Is Styrofoam Toxic?

Yes, it is. The U.S. National Toxicology Program stated that styrofoam is a likely human carcinogen, which is expected to cause cancer. Studies also show the building block of styrofoam, styrene, disrupts horses in the body, causing liver and nervous tissue damage.

In addition, styrofoam is made from expandable plastic; it's non-biodegradable, so it can cause pollution.

How to Put Out A Fire From Styrofoam

If you're wondering how to put out a fire from styrofoam, the best thing to do is extinguish it correctly with any extinguishing agent. Some people opt for fire blankets or pot lids to smother the flames, ensuring you don't have any gaps around the edges. But these techniques only work with smaller fires.

Use extinguishing foam, powder, sand, or dry chemicals to be extra safe. Once you've got the fire extinguisher, removing the styrofoam from the area immediately is essential. The fumes from burning styrofoam can be toxic, so you want to avoid sticking around in a room full of them.

If you can't remove the styrofoam, you must ventilate the area as much as possible. Open all the windows and doors and get a fan going. If you've inhaled fumes and feel irritated, seek medical help immediately.

Is Styrofoam Toxic

Safety Precautions For Handling Your Styrofoam

Take these steps to ensure your safety as well as anyone else working with styrofoam.

Keep Your Styrofoam Products Away From Open Flames Or Fire

Styrofoam should be appropriately stored. When used for craft projects, keep it away from small children and pets who might mistake it for something to eat. Also, don't store styrofoam near any heat source, including radiators, heaters, and electrical sparks.

Ensure Proper Disposal 

You shouldn't burn it because of the release of gases. You also shouldn't throw it away because it's not biodegradable. Hence, it's harmful to the environment. The best option is to drop it off at the nearest recycling center. Alternatively, you could upcycle your styrofoam by repurposing it and making crafts and decorations for your home.

Contain Any Fires Caused By Styrofoam

Styrofoam may not be flammable, but it's still combustible and will burn. The by-products are just as harmful as the spread of the fire itself. The styrene gas released from its decomposition is carcinogenic (cancer-causing) and damages the neurological system. So if you use styrofoam often, always keep a fire extinguisher handy.

Final Thoughts 

So, is styrofoam flammable? You should have your answer now. The answer is a little complicated. But in general, you should err on the side of caution, assume that styrofoam is flammable, and keep it away from open flames or sparks.