Can You Microwave Styrofoam Takeout Boxes?

Ordering takeout is very common today, whether for lunch, supper, and more.

Sometimes it’s more convenient when you’re fatigued after a busy day.

Can you microwave styrofoam takeout boxes? In this article , I’ll take you through everything you need to know about microwaving styrofoam.

Let’s get started!

What are Styrofoam Takeout Boxes?

A Styrofoam food container is a form of disposable food packaging for various foods and beverages, such as coffee, processed instant noodles, or cooked food from restaurants.

They are also commonly used to serve takeout food from restaurants and also for those diners who wish to take home their leftovers.   

They are good thermal insulators, making the container easy to carry as well as maintaining your food temperature.

Is it Safe to Microwave Styrofoam Takeout Boxes? 

Styrofoam takeout boxes are polystyrene containers but are only safe if they have a microwave-safe label.

Unless you check the label their safety cannot be guaranteed.

How do you know the Styrofoam is Safe to Microwave?

To determine if a foam container is microwave-safe, look for a small symbol of a microwave with wavy lines.

That symbol means the container is safe for microwaving.

If the container lacks that symbol, it is not safe to use in the microwave.

How Long Can You Microwave Styrofoam Takeout Container?

You can surely microwave Styrofoam for 30 seconds, but not more than that.

If the temperature of the material reaches more than 200 degrees Celsius or more, the Styrofoam will start to melt.

Avoid overheating the Styrofoam as it releases toxins that pose a danger to your health when ingested.

Can You Put Styrofoam in a Microwave to Defrost?

No! Styrofoam containers cannot be put in a microwave to defrost.

Foam is a plastic like any other and it is not heat stable at high temperatures.

Melting or warping may cause harmful chemicals to migrate into the food.

Can you Microwave Styrofoam Cups?

Yes, you can microwave and heat Styrofoam cups.

Although, you should check whether the cup is labeled microwave-safe.

Not all kinds of Styrofoam cups are safe for microwaving.

Does Microwaving Styrofoam Cause Cancer?

Microwaving food or drinks in Styrofoam does likely increase your chances of getting cancer.

Some studies have shown styrene is a probable carcinogen and likely to cause cancer.

How Does Styrofoam Cause Cancer when Microwaved?

Styrofoam is either polystyrene or expanded polystyrene.

Polystyrene is made from styrene which is polymerized together to create polystyrene beads.

Styrene itself has been proven to remain as a residual in Styrofoam cups, bowls, plates, and other containers.

The most recent styrene studies have shown the risk of acute myeloid leukemia, a rare form of leukemia, is doubled.

When microwaving Styrofoam, harmful toxins leach into the food or drink that is being heated, these toxins become carcinogenic increasing the risk of cancer.

Can you Reheat using Styrofoam Takeout Boxes in a Microwave?

Yes. While some people are apprehensive of putting Styrofoam in the microwave, Styrofoam, in reality, is not plastic.

In fact, it is a foam-like lightweight variant of plastic that is actually safe to be put in a microwave for reheating.

What are the Ways to Reheat Food Safely in Styrofoam Containers Using a Microwave?

It is important to follow certain steps while reheating Styrofoam to avoid toxins leaching into your food.

Those steps are:

Step 1:Check the microwave-safe label on your Styrofoam container.

Step 2:Place the container in the microwave and cover it to avoid spilling your food.

Step 3:Heat for not more than 30 seconds and remove.

Be careful when removing the container to avoid burns.

Do not overheat to avoid toxins leaching into your food.

Frequently Asked Questions

What happens if you microwave Styrofoam?

Microwaving Styrofoam containers are safe only when done for thirty seconds and at a temperature of less than 200 degrees Celsius.

What chemicals are released when you microwave Styrofoam?

Even if you do not see damage to the foam, a microwave can cause a toxic chemical called styrene and other chemicals to leach into food.

Is Styrofoam toxic when heated?

When exposed to heat, Styrofoam breaks down releasing toxic chemicals.

How toxic are Styrofoam fumes?

When Styrofoam is burned it emits carbon dioxide, carbon monoxide, water vapor, and soot.

These gasses are toxic for consumption and inhalation.

Can you microwave soup in a Styrofoam box?

No! Microwaving soup in a Styrofoam container is not advisable, this is due to the endocrine-disrupting compounds that can be released in the soup.

What is the rate of the risk posed by microwaving Styrofoam?

Scientists say that the cancer risk posed by styrene is low due to small amounts in consumer products.

Consumers are said to be most likely exposed to the toxins, but there has to be a long-term exposure that leads to cancer.

What does Styrofoam do to our body when microwaved?

Styrene, the main product in polystyrene foam, is likely human carcinogenic.

In people, it increases the risk of leukemia and lymphomas.

Can Styrofoam catch fire in the microwave?

Yes, they can catch fire especially when the content is little.

Does Styrofoam melt in the microwave?

Styrofoam is not heat stable, so when exposed to very high temperatures it will melt.

In fact, you should avoid heating at temperatures higher than 200 degrees Celsius, and for a long time.

What is the difference between the old version of Styrofoam and the new version?

The old version of Styrofoam was not microwave-friendly.

The new version is more microwave-friendly and is also partly organic.

High Risks Associated with Microwaving Styrofoam

Here are some of the health risks associated with Styrofoam exposure:

  • Stomachache
  • Headache
  • Fatigue
  • Depression
  • Hearing loss
  • Nervous system dysfunction

Pros and cons of microwaving Styrofoam


  • Fast and economical


  • Pose a major health risk
  • Can melt.
  • Release toxins that leach into the food.

Ways of knowing your Styrofoam is safe

Safe microwavable plastics are marked 1, 2, 4, or 5.

Avoid those marked;

#7- They are usually polycarbonates, but may be other types of nonrecyclable plastic.

#3- These are PVC plastics.

#6- They have polystyrene that can cause damage to the brain and nervous system.

Dangers of microwaving Styrofoam

  • It can melt.
  • Releases toxins that leach into your food.
  • Long-term exposure causes cancer.
  • Food might lose taste.
  • Releases toxic fumes especially when it melts. 

Bottom Line

Avoid using Styrofoam in the microwave but if you do not have an option, make sure you check if the plastic is microwave-safe or not. 

Some states in America have banned the use of Styrofoam because of the health risks it poses to human health and to the environment.

This does not only account for Styrofoam, it accounts for all plastic containers, so avoid microwaving them.

Use microwave-safe containers that have been proven to be safe and have little risk of causing any danger to your health.

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