Is It Safe To Microwave Styrofoam? [ Health Risks & Safety Tips ]

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This article is written by:

Zornitsa Stoycheva

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What is styrofoam?

Is it safe to reheat food in Styrofoam?

How to Reheat Food Safely

Conclusion

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Some materials, such as styrofoam, are not microwave-safe and should never be microwaved.

Be sure to check your food packaging for microwaving instructions before popping that container of leftovers into the oven. Microwaves heat up food from the inside out, cooking it from the core through its surface.

And just because a dish is labeled “microwave-safe” doesn’t mean it’s actually safe to put in the microwave! Some plastics can release a toxic chemical called dioxin when heated up in a microwave oven – so don’t risk it! Check with your manufacturer or contact them directly if you have any questions about whether or not an item is safe to use in a microwave.

Table of Contents

What is styrofoam?
Is it safe to reheat food in Styrofoam?
1. Can styrofoam catch on fire in the microwave?
2. Can you microwave styrofoam?
How to Reheat Food Safely
Conclusion

What is styrofoam?

Styrofoam is a trademarked name brand of closed-cell extruded polystyrene foam. Styrofoam is а type of plastic and is manufactured primarily for thermal insulation purposes (walls, floors, and roofs) in the building sector and construction industry.

It’s made from polystyrene foam or plastic foam. Styrofoam has been also used extensively to package perishables and other products requiring a high degree of insulation. In fact, about 40% of the Styrofoam used in the United States is used for food packaging. ^[1]

Is it safe to reheat food in Styrofoam?

The answer is no. Styrofoam is not food safe, and reheating food in styrofoam may even lead to health problems. But what health risks are associated with reheating food in styrofoam?

Health risks associated with styrofoam exposure or intake are ^[2]:

Stomachache
Irritation of eyes and nose
Headache
Fatigue
Depression
Hearing loss
Nervous system dysfunction

Styrofoam is porous, which means that it can absorb the oily residue of foods. When reheated oils are absorbed into the styrofoam, they are reheated again (while reheating the food). The reheated oils may begin breaking down and releasing chemicals that are unsafe for humans.

Additionally, styrofoam tends to break down over time, which means pieces of styrofoam could end up in your reheated food.

That being said, foam food packages that are labeled “microwavable” are likely safe if heated to up to 212 degrees Fahrenheit. ^[3] Yet, these are not intended for repeated heating or reuse.

Can styrofoam catch on fire in the microwave?

According to styrofoam.com, styrofoam cups can catch on fire in the microwave when in use for long periods of time with little water in it. For that reason, some styrofoam packages have a warning label that states “Caution: Do not heat this product…”

If styrofoam starts burning, it will start to release smoke and will shrink.

That being said, styrofoam can also be used to hold hot food with no problems. It is unlikely to catch on fire unless neglected for a long period of time.

Can you microwave styrofoam?

Styrofoam is made of a substance called Expanded PolyStyrene Foam (EPS). It’s not safe to microwave any type of EPS, styrofoam or no styrofoam.

Styrofoam contains styrene, a chemical which can leach into food during microwaving at high heat. By eating the food, styrene particles may enter your body and cause various health risks. In fact, there have been reports (with limited evidence) of styrene being linked to cancer development. ^[4] .

Don’t miss out: Why Is BPA Bad For Your Health? [ & How To Limit BPA Exposure ]

How to Reheat Food Safely

There are many different options depending on how quickly you need to reheat food and what type of food you want reheated. Here is a list of quick reheating methods to choose from: microwave, oven and stovetop.

reheating food in microwave oven

Oven: Preheat an oven at 350 degrees Fahrenheit for 5 minutes and then turn it off prior to reheating your food. Place your container with your food inside, sealed, and reheat for 5-10 minutes or until desired temperature is reached. This method can be used with many foods but remember to never reheat your food in plastic containers.

Stovetop: Place a pot on the stove over low heat and place your sealed container inside for 5 minutes or until reheated.

Microwave: Place the food directly on a paper towel and place it in the microwave for 1 minute or just until it reaches the desired temperature. Using a small amount of water when you microwave your food can create steam and this way, steam-heat the food. This method can keep more vitamins and minerals into your food than other cooking methods. ^[5]

*Microwave ovens are often blamed to cause cancer when used often, as they use radiation technology to heat food. However, studies show that microwaving your food is safe, doesn’t make it radioactive and is not linked to cancer development. ^[6]

Conclusion

Microwaving styrofoam is not recommended because it may release toxic gases and start to melt (unless labeled “microwavable” and heated up to 212 degrees Fahrenheit). Styrofoam containers are made of polystyrene which decomposes, no matter how clean the container is when heated up.

Quick and safe ways to reheat your food are using oven, microwave or stovetop methods instead.

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