How Long Can You Microwave Styrofoam? (Answered)

When microwaved for a long time, Styrofoam containers can be a threat to your health. They are also unfavorable to the planet.

Speaking of Styrofoam, is it safe to use in the microwave? Well, some Styrofoam containers are manufactured in a way that allows usage in the microwave while others are not.

And how long can you microwave Styrofoam? You can microwave Styrofoam under medium heat for 30 seconds only. Exceed the time, and it’ll most likely start to melt and release toxic chemicals.

In this post, we’ll learn more about Styrofoam containers and how you can safely use them in the microwave.

Keep reading!

What is Styrofoam?

Styrofoam is a trademark of Dow Chemicals known for all types of plastic foam material. The foam, which is usually used in several programs, is a petroleum-based substance generated from benzene and styrene.

Its composition is roughly 95% air, a feature that makes it lightweight. It is also unsinkable, doesn’t break down or lose shape.

Types of Styrofoam Containers

Styrofoam containers include:

1. Styrofoam plates: Styrofoam plates are a cheap alternative for persons who like hosting. They are inexpensive, disposable and can be used to reheat food.

2. Coffee cups: Styrofoam coffee cups come in handy when you have lots of guests to serve coffee or hot chocolate. They also make a cheap alternative to small bowls for serving stews and soups.

3. Takeout containers: These takeout containers are usually used when ordering out or taking leftovers home from the restaurant. They come in handy since instead of removing the food and heating it in another dish, all you need to do is toss the container in the microwave.

4. Cup noodles: Cup noodles hold instant noodles. They usually have 2 sets of directions – one for adding boiling water and another that might suggest filling with cold water and then microwaving it.

Is it Safe to Microwave Styrofoam?

Not all Styrofoam containers are safe to use in the microwave.

Styrofoam can melt when exposed to high temperatures and contaminate your food with toxic chemicals. Only use microwave-safe Styrofoam when heating your food in the appliance.

And how do you know that a Styrofoam container is microwave-safe? By simply checking for the microwave-safe label.

Also, remember to microwave the microwavable container for not more than 20 minutes under medium heat. It’s the only way to keep the container safe from damage.

Can You Microwave Styrofoam for 30 Seconds?

If you can avoid microwaving Styrofoam, the better. However, if the situation gives you no alternative, you can still use it to reheat your food or beverages.

How Long Can You Microwave Styrofoam

The first thing to do is ascertain that the container is microwave safe. If it is, you should see a microwave-safe label on it.

Microwavable Styrofoam containers are safe to use as they limit the release of toxins. In fact, they are FDA approved and usually come with a label stating the same.

Always microwave Styrofoam containers under medium-level heat.

Tips to Microwave Styrofoam

If you usually microwave Styrofoam cups or plates often, you need to familiarize yourself with the following tips:

  • Look for the label

Before placing a Styrofoam container in the microwave, you need to confirm that it’s microwavable. If it’s microwave safe, the manufacturer usually provides a label to let you know that you can use it in the appliance.

If the container doesn’t come with the label, don’t place it in your microwave.

  • Check whether it’s FDA Approved

An FDA label confirms that the container is safe to use. You’ll most likely find it on the bottom of the Styrofoam container. If it’s FDA approved, it is safe to microwave.

  • Ensure it can withstand heat

Traditional Styrofoam is vulnerable to heat and can release toxins when heated. The newer version of microwavable Styrofoam is made from superior materials that are more resistant to heat.

  • Open the vent

Although most individuals like covering their food when reheating it in the microwave, it’s not a recommended practice. Yes, it’ll prevent food splatter and help cook faster, but it can cause overheating.


Q. Can you microwave coffee in Styrofoam?

Coffee is no different from food or any other beverage that you put in a Styrofoam cup. The only way to microwave it is by using a microwave-safe Styrofoam cup or container.

Q. What are the side effects of Styrofoam?

Potential health side effects that can result from heating Styrofoam and ingesting its chemical components include dysfunction of the central nervous system, fatigue, headaches, clinical depression, stomach irritation and hearing loss.

Q. What are the substitutes for Styrofoam?

Some of the best alternatives to Styrofoam include glass, Pyrex bowls or ceramic.

Q. Can microwaving Styrofoam cause cancer?

Styrene, a chemical in polystyrene, has been linked with cancer. It has actually been listed as a possible carcinogen.

However, since the risks of microwaving Styrofoam have not yet been proven, it’s hard to tell whether it releases enough of these chemicals to cause cancer.

Q. Can I microwave my food safely in Styrofoam?

You can microwave food in Styrofoam containers labeled microwave safe(source). Avoid containers without this label in the microwave.

Q. Can melted Styrofoam make you sick?

A small amount of melted Styrofoam accidentally ingested will most likely not harm your body. Large amounts can get stuck in your stomach or intestines and end up blocking the system.

Q. What happens if I inhale burnt Styrofoam?

Symptoms of short-term exposure to burnt Styrofoam include mild irritation of the eyes or throat and coughing. Long-term exposure causes lung-related issues like bronchitis, chronic cough, reduction of lung function or scarring.

Q. At what temperature does Styrofoam melt?

Styrofoam melts at 464 degrees Fahrenheit.


If you intend to microwave food in a Styrofoam container, don’t reheat it for more than 30 seconds on medium power. Any higher power will most likely melt the Styrofoam, especially if heated for a longer period.

And although microwave-safe Styrofoam can withstand standard reheating, don’t microwave it for too long as well. It can melt and leach toxic chemicals into your food.