Can You Microwave Styrofoam? (Here’s What You Need to Know…)

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can you microwave styrofoam

Quick Answer: Yes, but only if there's a label indicating that the Styrofoam is microwave-safe.

Still, there are certain rules to abide by and caveats about heating Styrofoam in the microwave, which we're going to explain in detail.

But let's find out what Styrofoam is first...

What Is Styrofoam?

Styrofoam is a bit of a mystery. You can't recycle it, there's confusion as to whether you can put it in the microwave or not, and people usually don't really know what it's even made of.

When we think of Styrofoam, we tend to just recall those plasticky, semi-mushy containers restaurants put to-go food orders in.

In fact, expanded polystyrene, a.k.a. Styrofoam, is a type of inert foam plastic used to make food containers, insulation, packaging and much more.

Here are some of the common items Styrofoam is used in:

  • Microwaves
  • Refrigerators
  • Auto panels
  • Couches and chairs
  • Wall insulation
  • Shipping package peanuts
  • Disposable cups

Different Types of Styrofoam Containers and Utensils

There are tons of Styrofoam food containers and utensils on the market. If you visit a typical restaurant kitchen or coffee shop, you'll probably find any of the following Styrofoam products:

  • Clamshell food containers
  • Soup cups
  • Coffee or beverage cups
  • Spoons, forks and knives

It's also not uncommon to see Styrofoam plates, bowls and trays at parties. One of the reasons this material is so popular is that it's super light and easy to transport, composed of 95 percent air. It's also low-cost, as you may have noticed if you've ever purchased Styrofoam plates before.

How Do You Know If Styrofoam Is Microwave Safe or Not?

Have you heard that you should never microwave Styrofoam? There is some truth to that. The thing is, you shouldn't microwave Styrofoam that doesn't have the label that marks it as microwave-safe.

While some feel that you can get away with microwaving Styrofoam on low heat for short periods of time, you still run the risk of melting the Styrofoam and ruining your microwave. This is a huge reason why you should only use microwave-safe cookware and containers, especially when they're made of plastic like Styrofoam.

There are also hazardous chemicals that can leach out of heated plastics and into your food and drinks, notably bisphenol A, or BPA, and styrene. BPA is known to mess with hormones and styrene can cause gastrointestinal, respiratory and other health problems.

It should be noted, however, that a microwave-safe label just means that the Styrofoam won't melt, not that it won't leach chemicals.

One more issue with microwaving no-label Styrofoam is that you never know what other materials are mixed in. There are plenty that should never be put in the microwave for your own safety, and there's no ingredient list on Styrofoam like on a food package.

Bottom line: Whether or not you want to microwave Styrofoam is up to you, but you should only ever microwave Styrofoam with the safety label on it so that it doesn't melt.

For tips on purchasing the best microwave, check out Our Top Microwave Toaster Oven Picks.

Labels on Styrofoam to Be Aware Of

Styrofoam and other plastics that just have the numbers 3, 6 and 7 in the recycling labels should never be microwaved.

What you want to see is a label that indicates "microwave safe" in clear language. Otherwise, heat your food up in another container you know is microwavable.

Bonus Safety Tips

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