Can You Microwave Styrofoam and Is it Safe?

By John Cruz

Can you microwave styrofoam?

That’s a question I’ve been asking myself since I was a kid and I don’t think I’ve ever really accepted or understood any of the answers I was given.

I think a big part of that is the fact that transferring that leftover Chinese takeout to a real plate takes away the convenience and gives me more stuff to do.

I guess you can call me lazy, but you’re probably in the same boat.

For those of you wondering, the answer is quite simple but can be complicated, depending on how your brain works.

Not all containers are microwave-safe, and using the wrong one could have some serious consequences.

The one common container often used for takeout food or leftovers is styrofoam, which I have a love-hate relationship with.

But can you safely microwave styrofoam takeout containers and plates?

The answer to this question largely depends on the type of styrofoam you’re using.

Contrary to popular belief, some styrofoam products are microwave-safe, while others are not.

The key lies in understanding the properties of styrofoam and knowing which ones can withstand microwave radiation without causing harm to your food or health.

To ensure the safety of your food and the health of your microwave, it is a must that you use appropriate kitchenware.

But first, let’s see what this so-called styrofoam is all about.

Can You Microwave Styrofoam?


You can microwave some styrofoam, but you need to understand which one.

For the most part, you can gauge a styrofoam just by looking at it.

You can pretty much feel if a styrofoam will be strong enough to be put in a microwave or if it will melt in just a few seconds.

It’s those cheap, thin styrofoam containers that you won’t consider reusing.

However, there’s more to know about styrofoam than you think, so let’s dig a little deeper.

Styrofoam is Actually a Brand

Yup, styrofoam has become a household name but believe it or not, it is actually a brand name.

It is a trademarked brand name for a type of extruded polystyrene foam (XPS).

It is made by mixing polystyrene beads, a blowing agent, and other chemicals together.

The mixture is heated to form a liquid, which is then extruded through a die.

As it cools, the blowing agent turns into gas, creating the characteristic foam structure.

Interesting, huh?

The primary component of Styrofoam is polystyrene, a petroleum-based plastic material.

It consists of long chains of styrene molecules, making it durable and lightweight.

  • Key components of Styrofoam:
    • Polystyrene beads
    • Blowing agent
    • Other chemicals

Properties of Styrofoam

Styrofoam is known for its excellent insulating properties, which is one of the main reasons it is widely used in various applications.

The gas-filled pockets created during the manufacturing process give it low thermal conductivity, meaning it can effectively slow down the transfer of heat.

Some key properties of Styrofoam include:

  • Lightweight: This makes it easy to handle and transport
  • Water-resistant: It does not absorb water, making it suitable for use in wet environments
  • Durable: It can withstand general wear and tear, which is why it is commonly used as packaging material and to-go containers

Different Types of Styrofoam

Although Styrofoam is often used as a generic term for all foamed polystyrene products, there are actually different types of polystyrene foams available, each with its own specific uses.

  • Expanded Polystyrene (EPS): EPS is a bead-like foam, often used as the base material for disposable cups and plates, as well as for insulation and packaging.
  • Extruded Polystyrene (XPS): XPS is the type commonly referred to as Styrofoam, and it is used for a wide range of purposes, such as insulation, craft projects, and construction.
  • Molded Polystyrene (MPS): MPS isn’t used as frequently but can be found in applications like floating docks and some protective packaging.

Different Styrofoam types are employed based on factors such as required thermal insulation, cost-effectiveness, and ease of production.

The Microwaving-Safe Process


Before deciding to microwave styrofoam, it is important to check if it is microwave-safe.

This can be done by looking for a microwave-safe symbol or label on the container.

In case it is not labeled, it’s best to avoid microwaving the styrofoam.

Once you have verified that the styrofoam is microwave-safe, you can proceed with the following steps:

  1. Place the styrofoam container on a microwave-safe plate. This provides additional support and catches any spills that may occur during the heating process.
  2. Use a microwave-safe cover or wax paper to cover the container. This helps to prevent food from splattering onto the microwave walls and keeps your microwave clean. Do not use plastic wraps as they may melt and release harmful chemicals.
  3. Set the microwave power level to low or medium. High heat can cause the styrofoam to release harmful chemicals, so it’s best to keep the temperature moderate.
  4. Microwave the food for short intervals. To prevent overheating, check the food periodically and stir it to ensure even heating.
Do’s and Don’ts in Microwaving Styrofoam
Check for microwave-safe label
Use a microwave-safe cover
Set the power level to low or medium
Heat for short intervals
Microwave unlabeled styrofoam
Use plastic wrap as a cover
Heat on high power settings

By following these guidelines, you can heat your food in styrofoam containers in a safe and efficient manner.

Always remember to prioritize safety and use only microwave-safe materials to prevent any health hazards.

Risks and Dangers of Microwaving Styrofoam


When heating food or beverages in the microwave, always consider the safety and potential hazards of the container used.

Styrofoam, also known as polystyrene foam, presents various risks and dangers when microwaved.

Chemical Leaching

One major concern when microwaving styrofoam is the release of harmful chemicals.

Styrofoam contains * styrene *, a suspected carcinogen, and * benzene *, a known carcinogen.

When exposed to heat, these chemicals may leach from the container into your food or drink, and ingesting them may pose long-term health risks.

Melting and Warping

Another risk associated with microwaving styrofoam is melting or warping.

When exposed to high temperatures or prolonged heating, styrofoam may begin to soften or deform, which you have probably seen before.

The melted or deformed foam can contaminate your food and be difficult to remove.

Moreover, the release of toxic fumes from heated styrofoam can be hazardous to both your health and the environment.

Fire Hazard

Although not as common, microwaving styrofoam can pose a fire hazard.

When subjected to excessive heat, styrofoam might catch fire and cause damage to your microwave and home.

To ensure the safety of your food and yourself, consider these guidelines:

  • Check for the microwave-safe label: Some styrofoam containers are labeled as microwave-safe, and their design minimizes the risks mentioned above. However, it’s still best to use caution and follow the manufacturer’s guidelines.
  • Use alternative containers: Opt for microwave-safe materials such as glass, ceramic, or plastic containers with a microwave-safe symbol.
  • Avoid microwaving oily or fatty foods in styrofoam: High-fat content foods increase the risk of melting and warping the container.

Microwaving styrofoam has its risks and it’s almost obvious that you shouldn’t microwave styrofoam.

To prevent any mishaps, it’s best to not microwave styrofoam or monitor what is going on in your microwave.

Safe Alternatives to Using Styrofoam in Microwaves


When heating up your food in the microwave, it’s essential to choose the right type of container. Here are some safe alternatives to Styrofoam that you can use:

  1. Glass containers: Glass is an excellent choice for microwaving food, as it doesn’t release any harmful chemicals and can handle high heat. Make sure to use microwave-safe glass and avoid containers with metallic or gold paint.
  2. Ceramic dishes: Ceramic is another great option, as it’s durable and distributes heat evenly. Choose microwave-safe ceramic, as some older decorative dishes may not be suitable.
  3. Microwave-safe plastic: Although some plastics can release harmful chemicals when heated, there are also microwave-safe options available. Look for containers labeled “microwave-safe,” “BPA-free,” or “heat-resistant.”

Here are some tips for choosing the right microwave-safe container:

  • Check for a microwave-safe symbol, usually depicted as a series of wavy lines.
  • Avoid using plastic containers with a code of 3 (PVC) or 6 (polystyrene), as they can release harmful chemicals when heated.
  • Do not place plastic wrap directly onto food, as it can melt and release chemicals. Use parchment paper or microwave-safe covers.

Additionally, here’s a brief comparison table of the three safe alternatives:

GlassChemical-free, high heat resistanceCan be heavy, breakable
CeramicDurable, even heat distributionCan be heavy, decorative paint may not be microwave-safe
Microwave-safe plasticLightweight, affordableSome may contain harmful chemicals

Can You Microwave Styrofoam?

After all that’s been said, I hope you have a clear understanding of whether or not you can microwave styrofoam.

Personally, if I’m going to heat something up for more than a minute, I would stay away from styrofoam and plastic completely.

Sometimes you have to stop being lazy and pull out a microwave-safe dish to heat up that orange chicken and fried rice.

There’s no need to risk your health just for the comfort of having warm food.

I hope this post was helpful and I’m sure you all have your two cents.

Now, you tell me, can you microwave styrofoam?


About the author

With four humans of his own, John is our parenting expert. He loves being a dad, and when he's not trying to work on his golf game, you'll find him at his kid's soccer games or at the mall with his kids.

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