Can You Microwave Styrofoam? (What You Need to Know)

Nowadays, with the world around us moving so fast, most of us are busy in our hectic lives, completing one task after another. Humanity has evolved to keep up with these fast times. Thank god we have various machines that help us do tasks only in a few seconds or minutes now!

Like all the other new adults developing an understanding of how to keep up with a professional life, I got a little too immersed in my tasks. My company didn’t have a proper cafeteria. Also, we had a strict enough schedule that made full-fledged lunch breaks infeasible. 

Leaving lunch completely and then not having energy for work was not an option. So some of my colleagues and I began to order takeout. The food came in styrofoam takeout boxes which made us all stop for a moment. We wondered whether it was possible to microwave them. 

To preserve my eating habits, I took on myself to answer this question. And today I will be sharing with you all I learned about microwaving styrofoam takeout boxes.

Can You Microwave Styrofoam?

can you microwave styrofoam

Yes! You can microwave styrofoam once you’ve read the label on the box to see if it is microwave friendly. 

If the box mentions that it is microwave friendly, you can put it into the microwave without worries. But if you can’t see any sign of whether it is microwavable, it is better to stay on the safe side and not microwave the takeout box.

Two types of styrofoams are used to make products like takeout boxes, cups, etc. One is the traditional styrofoam. The other is microwave-safe styrofoam.

You are not supposed to microwave regular styrofoam. It is an absolute no! It can melt and break down once heated in the microwave. This can be very harmful to our health. Once melted, it produces toxic substances that can be absorbed by the food and lead to food poisoning or an emergency trip to the hospital.

But, if you’re using microwavable styrofoam takeout boxes, you can be relieved to know that they aren’t harmful. They are produced using substances that can handle the microwave better. You can tell that a box is microwavable by looking for three squiggly lines embossed on the surface of the box.

Can You Reheat Styrofoam Takeout Boxes In The Microwave?

It is best to avoid reheating styrofoam, as styrofoam wasn’t produced to be reused.

Too much exposure to heat can be a little risky, even if you are using microwavable styrofoam. This is because there is still going to be a threat of the styrofoam breaking down.

How Long Can You Heat Styrofoam Takeout Boxes In The Microwave?

First of all, ensure that your microwave is at medium to low power to make sure that excessive heat isn’t applied to the styrofoam. Heat the box for thirty-second intervals between which you can let it cool down for a second or two and then start the cycle again.

Another basic rule while microwaving styrofoam takeout boxes is to say no to high temperatures. It is better to steer clear of high temperatures even when using microwave-safe styrofoam. 

Heating food in the microwave does not take that long. Just like with most things in the microwave, it is a quick process. So you won’t have to wait too long to enjoy your food.

Is It Safe To Microwave Styrofoam Boxes?

Heating a regular styrofoam takeout box in the microwave can melt the styrofoam. This seeps toxic breakdown substances into the food. 

Hot fatty or sugary foods have a higher contamination probability. This is because the heat point of these foods is higher than the temperature of boiling water. Thus, they will heat up more and take a longer time to cool down. 

Even putting hot food in a traditional styrofoam takeout box can leak toxins into the food, let alone microwaving it!

This is where the most significant step and rule come in: never use traditional regular styrofoam. Only microwave microwave-friendly takeout boxes. Before microwaving the box, search for the microwave-safe symbol on the bottom of the box.

Is Styrofoam Toxic To Humans?

Styrofoam is a versatile material. It is used for both industrial purposes and daily life. If you start observing, you’ll notice this polymer in various places. The reason is that it is a cheap, lightweight, and widely available alternative to plastic and other materials.

Styrofoam contains a polymer, styrene. Styrene can be harmful to humans. When styrofoam melts, it produces toxic substances. When these toxins get absorbed by our tissues and bloodstream, they can be a threat to our human bodies.

Even low quantities of styrene taken in over a long period can be dangerous. The polymer builds up over time, causing side effects like nervousness, fatigue, or carcinogenic consequences.

It can also be bad for our psychological health as it can cause depression and even headaches. It is a threat to the nervous system and can result in an irregular menstrual cycle and more complex reproductive issues in women. 

Tips On Microwaving Styrofoam to go Boxes

Here are some of the tips that you should know and strictly follow when you microwave a styrofoam takeout:

  • Always use a Microwave-Safe Takeout Box: Ensure that your takeout box is microwave safe. If not, transfer the food to another microwave-safe styrofoam takeout box.
  • Make Sure You Have Not Used the Container Before: Styrofoam boxes are created for one-time use so make sure that you are not reusing a container. 
  • Remove Any Plastic: Make sure that no plastic wrap or plastic cutlery is coming in contact with the food. If it is, you should immediately remove it.
  • Check the Container for any Scratches/Dents/Cuts: If your takeout box has any of these three damaging attributes, put it away. It is best not to use it as some toxins can seep through these into the food and contaminate it.
  • Open the Box: Before putting the take-out box in the microwave, open its lid. This step is essential to avoid overheating the food above the melting point of styrofoam. Since steam has seven times the heat transfer rate compared to direct heat, venting the food is a key step.
  • Set the Microwave to Medium to Low Power: You don’t want the food you are just about to consume to be contaminated by toxic substances. Medium to low heat will prevent the styrofoam from melting. 
  • Heat for Thirty-Second Intervals: This step is also crucial to getting safe and healthy food. Only heat the food for thirty seconds at a time to avoid overheating and melting the styrofoam.
  • Stir Your Food: After each interval, take the food out for a few seconds to let it air and stir it. This will not only manage the temperature but will also heat the food evenly.
  • Be Careful While Removing the styrofoam from the Microwave: Hand it with care while removing the takeout box from the microwave. Wearing baking mittens or using a heat-resistant cloth will be helpful.


Being able to heat styrofoam takeout boxes is a blessing. Especially for all the lazy but hardworking individuals who have hectic jobs but would never give up on food! It takes absolutely no time at all, and you end up with food that tastes just as good as when it was fresh.

This shortcut to this very peeving question in my and my colleagues’ life left us all very relieved and comforted. This is truly the recipe to the beginning of a stress free life!

This tip doesn’t just have to be used in your professional life. You can also use it while heating leftovers or on lazy days when you don’t want to worry about doing the dishes. It is the knowledge that some might find random at first but later realize that it is invaluable!


Does the microwave-safe symbol indicate that styrofoam is safe to microwave?

Yes, the microwave-safe symbol suggests that a styrofoam container is safe to microwave. However, it is best to err on the side of caution and not microwave styrofoam, even if it has a microwave-safe symbol.

Is there a risk of cancer from microwaving styrofoam?

There is some evidence to suggest that the compound called styrene, which is found in styrofoam, can be harmful if it leaches into food that is heated in the microwave. While more research is needed, it is best to avoid microwaving styrofoam as a precaution.

Can to-go boxes be microwaved?

The safety of microwaving to-go boxes depends on the material they are made of. It is best to check the label for a “microwave safe” designation or to use an alternative, safer food containers when reheating food.

Are plastic and polystyrene containers safe to microwave?

Plastic and polystyrene containers are generally safe to microwave, as long as they are labeled as “microwave safe.” However, following the manufacturer’s instructions is important to ensure that the container does not become damaged or leach harmful chemicals into your food.

What is the difference between a polystyrene foam container and a foam container?

Polystyrene foam and foam are similar materials, but polystyrene foam is a specific type of foam that is made from the plastic polymer called polystyrene. Polystyrene foam is commonly used to make food containers, such as coffee cups and take-out boxes, while foam can refer to any type of cushioning material.

Are foam containers safe to microwave?

The safety of microwaving foam containers depends on the type of foam they are made of. Polystyrene foam is not recommended to be microwaved, while other types of foam, such as those made from silicone, may be safe to use in the microwave. It is important to check the label or manufacturer’s instructions before using a foam container in the microwave.

Can you reheat food in a polystyrene foam container?

It is not recommended to reheat food in a polystyrene foam container, as the heat generated by the microwave can cause the foam to melt, releasing harmful chemicals into your food. It is best to transfer the food to a microwave-safe container before reheating.

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