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How Long Should You Microwave Styrofoam? Is It Safe?

We all know of Styrofoam. Plenty of us use it in the form of containers to store our food in or get it delivered to us in takeout boxes. But the real question is, is Styrofoam microwave safe? Is it okay to microwave Styrofoam for 30 seconds?

This article will be providing you with all the answers you need to hear, touching on what Styrofoam is, the microwave, and health and safety.

How Long Should You Microwave Styrofoam

What is Styrofoam?

Before we go any further it is important to clarify what Styrofoam is.

Styrofoam is a type of polystyrene, trademarked by The Dow Chemical Company. It is often you’d find Styrofoam used as a container, finding takeout coffee cups and street food containers made with the polystyrene material.

It is safe to say that Styrofoam is a very popular choice for many for a variety of reasons. It is reliable, sturdy, well insulated and efficiently lightweight. All in all, it makes more sense to use Styrofoam than it would a heavier plastic container.

Styrofoam and the Environment

With good, however, comes the bad. Although Styrofoam holds many positive properties such as its convenience, it is unfortunately bad for the environment.

Today, we know more and more about what is good and bad for the planet, from littering to our use of plastics, and something else that we have learnt is of the harm Styrofoam can cause.

Compared to any other waste product, Styrofoam is one of the most littered items. Styrofoam is everywhere. People use this on the daily whilst they’re walking to work with a hot cup of coffee or if they’re sitting on a park bench with some street food.

And with more people using Styrofoam, this only leads to a larger amount of littering. In doing so people are not only harming the planet but are also harming each other.

  • Animals – Animals are one of the major species in harm’s way. You will often find that Styrofoam breaks up into little pieces and in turn this leads to chocking hazards for animals when they are scavenging.
  • Landfills – Landfills are fast becoming full, and 30% of that landfill waste across the world is Styrofoam. In the US alone, there is almost 2000 tons of Styrofoam buried in landfill which is only more detrimental to the environment.
  • Contamination – The Styrofoam that we use to hold our food and drinks in are more harmful to our bodies than you may think. Styrofoam contains something called Styrene, and that Styrene makes contact with our food and drink, thus contaminating the products. This is not healthy or efficient for the body and what is worse is that this is unknown to many.

Microwaving Styrofoam – Is It Safe?

Styrofoam has been paired with many negatives which cause people to doubt the safeness of microwaving Styrofoam. The most valid reason is the styrene in Styrofoam and how it releases bad chemicals (it has been learnt that styrene is one of the potential causes of cancer).

This links to how styrene can leak into microwaved food and drink, then entering and harming the body.

However, it is true that many people do indeed still microwave Styrofoam, and this can be for any of two reasons.

  1. They do not know of the harms of microwaving Styrofoam.
  2. They are using microwave safe Styrofoam.

Some cities in the United States have banned polystyrene containers because of concerns towards individuals’ health and the effects on the environment, but now they have come together to make microwavable Styrofoam containers.

Styrofoam containers are too convenient and efficient to get rid of completely, so people have come up with an idea to keep these containers whilst protecting the health of others.

The material used for these containers contain alterative materials to ensure safer use. It has a lower level of any harmful chemicals and in turn is safer when used in the microwave.

In order to tell which Styrofoam is microwave safe, it is important to look for the microwave safe label. If the container has this label, then that means that it has already been tested by the FDA (Food and Drug Administration) for safety.

Microwaving Styrofoam for 30 seconds

We know the harms that come with microwaving Styrofoam, of the risks of cancer and of the contamination caused by styrene, but does microwaving Styrofoam for 30 seconds make any difference.

The short answer is yes, it does make a difference.

When we speak of microwaving, we are talking about the process of heating something up, so this can be applied to other means of heating up Styrofoam such as in the oven.

What is most important is the temperature that it gets to. The toxins found in Styrofoam release once that temperature reaches around 435 degrees Fahrenheit and at that point is where the harm begins.

But only microwaving for 30 seconds can be doable. This is because the less time it is being heated, the less the temperature of the microwave will rise meaning the risk is much lower when it comes to toxins being released.

Despite all this, however, it is still important to be responsible when microwaving Styrofoam.

How To Microwave Styrofoam Responsibly?


When microwaving Styrofoam it is essential that you do so in the most responsible way possible. The worst thing you can do is risk your health and the health of the environment due to not going about microwaving in the correct way.

Below are a few handy tips for you to think about before microwaving Styrofoam.

  • Ventilation – When heating food it is common that you’d find people using microwave covers over their plates of food. People are known to do this to prevent the food from making a mess in the microwave as well as to trap more heat onto the plate.

When microwaving Styrofoam it is important to avoid this at all costs. By ventilating your food with a Styrofoam container you are preventing anything from overheating and ensuring your food will be safter to eat after it has been hated.

  • Vulnerability – It has already been covered that there are two types of Styrofoam – traditional and new. When going about microwaving traditional Styrofoam it is important to know its limits.

Styrofoam can be vulnerable in heat and may not be able to withstand it. Traditional Styrofoam in the microwave releases harmful toxins faster than it would in new Styrofoam.

  • FDA approved – The FDA stands for Food and Drug Administration and it is their job to protect the health of the public by providing safety and security to everyone. When looking into purchasing anything Styrofoam, make sure to look to see if it is FDA approved.

This can be found out easily. You may find that it may have a label on the product stating this or if it does not you are always able to look it up. The FDA is a reliable source as it is their duty to protect the safety of the people.

Before certain products are delivered to the public, they first test the product. Once the evaluation is complete they can go further, choosing whether it is safe or not safe for the public.

  • Overheating – it is very important to remember the 30 second rule. Heating any longer than this can cause many risks that you shouldn’t want to take.

It is easy to look past the health and safety properties, especially if you are only concerned with reheating your food, but it is important to keep this rule in the back of your head to prevent any future health and environmental problems.

The Alternative

With everything there is an alternative route. There have been many times where you may have some leftover takeout that you’ve left in the refrigerator in its Styrofoam container to have for tomorrow’s lunch.

The easy route is to throw that container with its contents into the microwave until it is hot enough to your satisfaction.

Alternatively, and arguably much safer, why not just transfer that Styrofoam covered food into a bowl or onto a plate? By doing this you will have no risks.

You can also decide to place the food into a microwavable container (there are plenty of microwave containers for sale in your everyday store). Once it is heated, you can then choose to keep eat it as it is, or you can choose to transfer it back into the Styrofoam container for easier travel use.

Final Thoughts

There are many pros and cons to Styrofoam however we have now found ways to make Styrofoam use much safer. Many businesses rely on Styrofoam for its efficiency and although it has many health and environmental risks, it is still needed for a large majority.

FDA approved alternatives are just as effective as your traditional Styrofoam containers and are better for the safety of the environment and your health. They are also safe to microwave. But what is the most important lesson learnt is keeping an eye on the time.

Make sure that when reheating using Styrofoam, do not heat for any longer than 30 seconds. Anywhere after that point can cause risks.

As long as you are heating responsibly and using the right recommended products, you will be safe.

Jess Smith