Can You Microwave Styrofoam?

Jason Loomis
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Two Types of Styrofoam

Regardless of whether Styrofoam is microwave safe, there are actually two different types of the material. Generically speaking, Styrofoam is a type of plastic that is commonly used to make, takeout containers, cups, and a variety of other consumer products. It is safe for use in the microwave.

There is a second type of Styrofoam that you might come across. This is Expanded Polystyrene Foam (EPS), which is an extruded form of Styrofoam that has been modified with air to make it softer. The result is that it is not as good at holding in heat as regular Styrofoam.

Just make sure that whatever you are going to put in the microwave is indeed a type of Styrofoam and not EPS. This will ensure that it will not melt in the microwave.

Okay, Let’s Talk Common Situations

The best practice is not to microwave Styrofoam. Styrofoam is actually a brand name, so technically you should not really say it in strict terms.

The studies have shown that the chemicals in Styrofoam can leak out into food when it is kept in the microwave. It is best to use different containers for cooking at high temperatures, but if you need to re-heat your food in the microwave, the best thing for you to do is to remove the microwave-safe cover that is used to keep the food warm.

Then add a plate or cover for the food and cover the plate with another cover that does not let the microwave rays through.

If you wash the Styrofoam containers in hot water, you should be able to find safe temperatures for reheating your food.

If your microwave has an adjustable temperature, you should be able to find a setting that works for the heating of your food.

Make sure that the container is not too big, because you will have to cover it with more microwave-safe materials to prevent any leaking of chemicals.

If the container itself has any holes, make sure to tape them up before using it. No matter what container you use, be sure that it is microwave safe and has not been previously microwaved.

The Bottom Line

While you may think that microwaving styrofoam will solve your problems, it’s best not to get into this habit. Styrofoam is a polystyrene foam. It is used as a disposable material for your takeaway coffee cup, to carry leftovers at work, and in every food container you use at home. It is one of the top 10 items on the beach clean-up list.

The problem with styrofoam is that it doesn’t easily decompose.

It is not toxic, but it takes 1,000 years before it disappears.

This is because it’s made of all polymers, which resist breaking down into smaller parts.

This means that when you heat up styrofoam in the microwave, you’re not killing bacteria, and you’re not sterilizing any infected product. What you are doing is heating up Styrofoam.

Why does it matter?

Because it wouldn’t be the first time that illness outbreaks have occurred from reheating Styrofoam food containers that had been stored in the freezer. Nor would it be the first time that more serious investigations were conducted into heating up Styrofoam in the microwave or the dangers associated with this practice.