Can You Microwave Styrofoam? | Chemicals Found in Styrofoam | Safety Precautions, How to Do It Right, Benefits & Potential Side Effects

Believe it or not, this question is one that’s been asked a lot of times - and more people don’t know that right answer compared to those who do. Read on to find out if you can microwave styrofoam.


Admit it - you’ve gotten home with some takeout food, or bringing leftovers from your restaurant dinner, and it comes in styrofoam containers. Sure, more and more companies and establishments are switching to more biodegradable and ecologically safe paper containers, but styrofoam users are still prevalent.

The basic idea is that styrofoam item contains materials that are potentially hazardous to health, and thus, aren’t recommendable to get mixed with your food or drinks. It contains aluminum foil and other metals that can cause negative health effects.

Can You Microwave Styrofoam?

There is a debate on the safety of microwaving styrofoam. If we take plastics for example, there are some kinds that are designed to be safe for microwave heating. Technically, styrofoam is a plastic. People argue over its safety for microwave use, but the point is that there are certain types of styrofoam that can be microwaved without causing adverse health effects.

The short answer: Yes, you can microwave styrofoam. However, we - and most health experts - would not recommend doing so. Learn more about the reasons and science behind this by reading on below. We’re taking a pros and cons approach to easily iron out this dilemma.

Styrofoam Containers

Styrofoam containers are used mainly in the food and beverage industry, particularly in these following forms:

  • Coffee Cups
  • Cup Noodle Containers
  • Styrofoam Plates
  • Takeout Food Containers with Lids.

Toxic Chemicals Found in Styrofoam

By learning about the materials found in styrofoam, we can better understand its toxicity towards health. One of the primary chemical materials in styrofoam is called Polystyrene. This compound is rich in toxic styrene and benzene molecules. These have been found to carry neurotoxic and carcinogenic properties, among other adverse health effects.

When heated, polystyrene is believed to have a certain level of these chemicals “seep” and attach to the food you are heating in the microwave.

In fact, several studies and reviews from the National Institute of Standards and Technology tell us that polystyrene starts to decompose at 200°C. During such conditions, trace amounts of the chemical compound are released.

If you think that’s bad, it gets worse as the temperature rises. Polystyrene breaks down at 224°C, while styrene in its pure form breaks down at just 175°C.

Obviously, heating anything in styrofoam containers at these temperatures (or higher) can definitely do more harm than good. Thinking of heating or cooking slabs of meat in the microwave at high temperatures for a long period of time? Scratch that idea!

Plus, the plastic properties in the styrofoam will absolutely melt in such heat. When heated in the microwave, or if it comes in contact with very hot items (food, drinks), the material will melt.

If you heat a cup of water in the microwave, the water will boil at 100°C. This is lower than the temperature needed for polystyrene to release its chemical compounds into the water. However, the cup at least partially get melted, so we can safely assume that some of the polystyrene has seeped into the water.

Even if you are ingesting a mere 10% of that styrofoam cup, that’s still 500mg of chemical polystyrene (if that cup is around 5 grams). This is considered by the EPA as the absolute upper limit of what we can call “safe” for human ingestion in the short term. It will totally be a different scenario if you always heat your styrofoam cups on a regular basis.

Dangers and Potential Side Effects of Ingesting Styrofoam

Polystyrene, on its own, is very flammable. Some manufacturers, however, add certain chemicals to the material to render it more resistant to fire.

The main thing to remember is that styrofoam is NOT designed for cooking purposes. First of all, they are very thin and non-durable. This isn’t just dangerous in terms of chemical compounds found in the styrofoam. Using them in cooking and intense heating can also create a real fire hazard.

Here are some of the health scares that can arise from ingesting styrofoam and the chemical components released when heated in the microwave:

  • Headaches
  • Irritation of the eye
  • Stomach upset
  • Fatigue
  • Hearing problems
  • Brain and nerve dysfunctions
  • Clinical depression.

Will Microwaving Styrofoam Lead to Cancer?

This is a valid question, since there have been a considerable amount of rumors pointing to this. This is mainly because of studies that link polystyrene with certain forms of cancer. In fact, polystyrene has been classified as a potential carcinogenic substance.

While more research and scientific data is still needed to pin down the risks of microwaving styrofoam, the best bet would be on staying on the safe side. Knowing the facts that chemical compounds might be released from its material is enough to stay away from heating the material in a microwave. It’s best to avoid any activities that can pose actual threats to our health.

Pros of Microwaving Styrofoam

Pros of Microwaving Styrofoam

Still, we have to look at both sides of the problem. So, despite the potential health risks, here are a few benefits of choosing to microwave styrofoam. It’s up to you to weigh down the risks versus the benefits.

  • It is convenient
  • Styrofoam is cheap and widely available
  • It is easy to dispose after use.

Do you think these pros outweigh the cons?


Until we come up with an entirely new way of manufacturing styrofoam to make it safe enough for microwave use, the bottom line is: Do not microwave styrofoam containers, especially if it’s for consumption of food or beverages. Choose other options to keep your health in check, which is way more important than convenience.

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