Can You Microwave Styrofoam? – Quick Informational Guide

When microwaving, knowing your food container is always vitally important: From the heartiest spaghetti to the tenderest of turkey, any meal can be made unsavory–or even toxic–if microwaved with the wrong type of container.

Many people seek out dishes marked “microwave-safe,” but certain locations with microwaves (like workplaces and hotels) may not offer containers with that special label. In some cases, Styrofoam is a quick and convenient option, but…can you microwave Styrofoam food containers? The truth is in the technique: When used delicately, Styrofoam can be safe, but in most cases, you’ll want to seek out an alternative. So the answer is it depends!

It is true that wrappings such as plastic Tupperware, aluminum foil, and metal containers are highly discouraged when it comes to microwaves. As Styrofoam is technically a type of plastic, overheating it can release certain chemicals, such as styrene, which can be hazardous.

As these chemicals can cause eye problems, gastrointestinal issues, and even signs of cancer if ingested continuously, many people try to avoid microwaving Styrofoam at all costs.

However, as mentioned before, there are a few situations in which microwaving Styrofoam is actually nothing to worry about. Here are a few components to keep in mind if you’re in a sticky–or rather, Styrofoamy–situation.

1. Some Styrofoam containers actually DO have a microwave-safe label.

Those ever-famous cups of noodles? Their Styrofoam is actually made to handle the heat. For containers that companies know will be heated, manufacturers specially design their Styrofoam to limit or avoid releasing toxins. These containers are approved by the FDA, and will often have a label stating so. Keep an eye out, and you’ll be good!

2. Temperature and time are key.

Untreated Styrofoam begins releasing toxins at around 392-435 degrees Fahrenheit (200-224 degrees Celsius). A microwave’s temperature can vary based on food, container, and wattage; but logically, microwaving something for 30 seconds is less likely to cause Styrofoam damage than nuking it for 5 minutes.

If the item needs only mild reheating, Styrofoam can be used safely for a short period of time.

(However, liquids overheat rapidly, so it’s smart to avoid those if possible. Also, if the Styrofoam melts or decays in any way, toss the meal entirely–even if you only microwaved for a few seconds.)

3. Venting the container can lead to safer cooking.

For food that can get messy in the heating process, it’s tempting to cover it entirely to avoid future clean-up. However, leaving no vent for a meal can cause it to overheat, making an even bigger mess of its Styrofoam container.

For the safest conditions, vent your dish: Slide any Styrofoam lid to the side (or remove it entirely), or cut slits in any disposable sealed cover. This will lower the risk of any chemical contamination, as it’ll keep the Styrofoam from melting quickly.

But what if your Styrofoam doesn’t fulfill these requirements? Well, for your safety and meal quality, it’s best to find an alternative. This is easier said than done, as microwave-safe dishes aren’t always immediately accessible, but there are some alternatives available to even the most desperate of microwave users.

1. If possible, use a glass or other microwave-safe container.

While it’s not an option for everyone, most people microwaving from home do have access to these dishes. Yes, it’s tempting to just shove a takeout box into the microwave so you won’t have to empty it onto a plate.

But having to wash that dirty dish later is a much better alternative to ingesting dangerous toxins. If you’ve got the right container, use it!

2. Try a non-Styrofoam paper plate.

While these can also be prone to melting if overheated, they usually do not share the potential toxicity of Styrofoam or other plastics. With these plates, it’s best to heat your food in short intervals and check it regularly for any damage as you do so.

Also, remember that greasier meals can cause the plate to break down more quickly in the microwave. Despite these precautions, with proper technique, paper plates can be a convenient and safe dish on which to cook your food.

3. Cook your food atop a paper towel.

Even if you can’t find a plate or container, paper towels are everywhere. If you have a meal that can be placed on a flat surface, this is a non-toxic and easy alternative to Styrofoam. As with paper plates, there are a few safety tips to keep in mind:

Try to avoid paper towels with elaborate ink designs, keep the towel flat and not crumpled, and remember that any form of paper can catch fire if cooked for too long. Also, lightly wetting the paper towel can lower hazard risks even further.

If worse comes to worst–let’s say you have soup that needs a proper container and Styrofoam is your only option–then a single microwave session shouldn’t cause too much worry. So long as you follow the precautions listed above and your Styrofoam shows no signs of melting, all should be well.

Still, it may be smart to consider buying one microwavable container specifically for work/trips/etc. Most of the effects of Styrofoam toxins are based on long-term use, so the more you can avoid it, the better.

Bottom line: When cooking with Styrofoam containers, the details matter. So be safe, be smart, and be Styrofoam-savvy.

Sources:, “Can You Microwave Styrofoam?”
Harvard Health Publications, “Microwaving Food in Plastic: Dangerous or Not?” “Can You Put Styrofoam in the Microwave?”

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