Is Styrofoam Microwavable? (Are All Styrofoam Microwave-safe?)


As most of us have a microwave oven at home, you could have probably asked this question before, “Is Styrofoam microwavable?” Is it safe to microwave food in Styrofoam or food container made of foam? Is it hazardous to our health?

Well, the answer to that is NO! It is not safe to microwave Styrofoam because it is a petroleum-based plastic product made from polystyrene and it is almost never safe to microwave any plastic or foam product.

What Happen When Styrofoam is Put Into Microwave?


The microwave is such a convenient kitchen appliance, but you need to be careful when using it. Microwaving Styrofoam is something you don’t want to do. When you microwave your food in Styrofoam containers, you will most likely smell plastic burning, and that could also mean that the toxic from the plastic which makes the Styrofoam container is leeching into your food.

​When you microwave Styrofoam, it doesn’t mean that the Styrofoam will melt right away. It would take up to more than 30 seconds and also at a temperature of 212 degrees Fahrenheit or above before the Styrofoam container starts melting.

​Now even if the Styrofoam container did not melt when you heat up your food in it, as we mentioned earlier, the toxins from the plastic product will leech into your food and goes into your body when you consume the food from the Styrofoam container which you heat your food in the microwave.

​You won’t get sick immediately or see the effects right away, but on the long run, it is extremely harmful to your body.

What Is Styrofoam and The Risk of Microwaving It?

One of the chemical contents in Styrofoam is a Styrene, and this compound is known for causing cancer disease, loss of vision and hearing, impaired memory and concentration and also attacks our nervous system.

​According to The National Toxicology Program (NTP), Styrene is reasonably anticipated to be a human carcinogen based on limited evidence of carcinogenicity from studies in humans, but sufficient studies in experimental animals, and supporting data on mechanisms of carcinogenesis.”

The NTP has reported that styrene could be a possible cause of cancer and workers in the manufacturing places that has been exposed to this chemical has a high risk of damage in white blood cells, lymphoma, and leukemia.

​Styrene has also been linked with other issues such as fatigue, headache, and respiratory problems. Although the US Department of Labor, Occupational Safety & Health Administration are aware of the adverse effects from Styrene, no action has yet been taken to limit its usage.

​That being said, if you are someone who often heats up food in containers made from Styrene, you might be experiencing irritation to your eyes and skin and also experiencing gastrointestinal problems.

Microwave-safe Styrofoam Containers


The usual Styrofoam appears to be foam-like, lightweight and is used to hold your food or drinks temporarily. But the truth is, there are two types of Styrofoam, the later which appears to be microwave-safe.

The original Styrofoam is as we mentioned above is made from polystyrene which contains chemicals like styrene and benzene which is carcinogenic and can damage reproductive systems and cause other several health problems. Which means. This traditional Styrofoam container is definitely not safe for microwaving.

Microwave-safe Styrofoam

Now, the second type of Styrofoam which is said to microwave-safe isn’t exactly like the usual Styrofoam, but it is on certain levels a similar product that is using different and safer materials with lower hazardous compounds. It is still called Styrofoam and could probably look the same, but it is manufactured in a way to withstand higher temperature.

This new version of Styrofoam is microwave safe to a certain extent. Extensive test on the materials to make this new type of Styrofoam has been done to ensure that whatever chemical that leech out is still safe to our health.

​If the Styrofoam passes the FDA review, there will be a notification on the material that is safe for microwaving. And how to tell if the Styrofoam is microwave-safe or not, just look at the bottom or the sides of the container for signs or warning.

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Types of Styrofoam Containers

  • Cup Noodles

    Can you microwave cup noodles? The type of material used for cup noodles is usually suitable for microwaving. However, it is still advisable to be sure and look at the instructions or label to check and see if the cup is suitable for microwave or not.

  • Styrofoam Plates

    Nowadays we don’t see much Styrofoam plates as they have become less popular in recent years and replaced by paper plates. Styrofoam plates are not suitable for microwave at all as it is designed for just holding food while you eat from it and throw away immediately.
  • Take-out Containers

    What about take-out Styrofoam boxes? Is Styrofoam take out box microwavable? I would recommend that if your takeaway food needs heating up, transfer it to a glass dish or bowl first before heating them up in the microwave. Most of the time, take-out containers are meant for storing the food for takeaways only and not suitable for microwave.
  • Coffee Cups

    Coffee cups are designed as a temporary holder, and immediate drink on the spot after the coffee is already heated. It is not made for the microwave and if you ever need to heat up your coffee in a microwave, consider pouring it into a regular mug before putting it in the microwave.

So, Is Styrofoam Microwavable?


To sum it all up, it is perhaps safer to not microwave any Styrofoam containers at all. If you really have no choice or needed to, do check first if the container is microwave-safe and even if it is microwave safe, try to keep the cooking time to not more than 30 seconds.

So, can you microwave Styrofoam?

​I think a safer answer to the question is a straight NO. Unless the Styrofoam containers state that it is microwave-safe and in that case, it is also wise to take precautions as the melted material may release toxic which may leech into your food.


Now you know the answer to “is styrofoam microwavable?” so it’s up to you to opt for a safer dish to use for microwave like the glass. Glass is not only safe but also environmental friendly. So start using glass today and cook healthy and safe.

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