The Truth About Microwaving Plastic Containers

Food being microwaved in a plastic container.Jimmy Tan via Flickr

Our parents or guardians probably taught us all the same basic lessons when it comes to safety, especially kitchen safety. One that many people are stuck on? Not microwaving food in plastic containers. This warning, whether you heard it online or from your family, has been widely circulated for many generations.

The real scare about this “unsafe” practice is that zapping plastic containers releases cancer-causing chemicals called dioxins into your food. The same goes for chemicals called “plasticizers” which are found in containers and also plastic wraps.

But the real question is, how true is this warning?

No offense to mom or dad, but it turns out this fact is false. There are no dioxins in plastic containers, nor does microwaving cause the chemicals to form.

As far as the rumor that harmful plasticizers will leach into food during cooking, this has slightly more truth to it. However, it’s still a warning that is greatly over-exaggerated. While it’s true that small amounts of this chemical can make their way into fatty foods during heating, studies have found that it is an incredibly small amount. There’s little evidence that the amounts to which we’re exposed pose a risk at all.

Detail of female hand while using the microwaversedlacek

Although these myths may have been hyped up, it’s still better to be safe than sorry. To be cautious, keep plastic wrap from touching your food during microwaving. If nothing else, this will prevent plastic from melting into your meal.

If you’re really concerned, the simple solution is to switch to a microwave safe container and not use plastic wrap. “Microwave safe containers” have been tested by the FDA and won’t melt. As a rule of thumb, keep in mind that most takeout containers, water bottles, and plastic tubs or jars made to hold margarine, yogurt, whipped topping, and foods such as cream cheese, mayonnaise, and mustard are not microwave-safe.

Likewise, microwavable takeout dinners are often labeled as “one-time use” and should not be reused after the initial heating.

Another fun fact is that styrofoam is fine to use as long as it’s labeled microwave safe, something many of us have avoided for years. Make sure to check the styrofoam container before microwaving, however.


One final tip for if you’re planning on still microwaving plastic containers: before microwaving food, it’s important to vent the container, which means you have to leave the lid ajar, or lift the edge of the cover.

Bottom line: as long as it’s made for the microwave, plastic is perfectly safe to use. Just goes to show you, you can’t believe everything you read on the internet.