Science

No, You Shouldn’t Microwave Plastic

Many containers say they’re “microwave-safe.” But what does that really mean?
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Published Dec. 8, 2023.

At some point or another, we’ve probably all microwaved a plastic food container full of food. Many of them say they’re microwave-safe, after all. So how bad could it be?

In fact, pretty bad. While scientists have known for a while that there are major health risks associated with heating plastic, a recent study brought this issue back into the spotlight over the summer.

Scientists at the University of Nebraska-Lincoln found that microwaving plastic containers and reusable food pouches released billions of microplastics and nanoplastics—tiny plastic particles—into the food those containers held.

How is this possible, given that many of those containers are supposed to be “microwave-safe”? And why does this release of micro- and nanoplastics matter? We turned to Laura Vandenberg, professor of Environmental Health Sciences at the University of Massachusetts Amherst, for more information. 

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What Does Microwave-Safe Mean?

Vandenberg explained that while many plastic food storage containers are advertised as “microwave-safe,” this designation just means that they have been proven not to melt, explode, or otherwise become damaged in the microwave. It doesn’t mean that they are safe from a health perspective. 

In fact, just like other plastics, “they will break down and release their chemical constituents into the foods and beverages that are stored in them”—a process that “can be accelerated when plastics are heated,” she said.

Why Is It Unsafe to Microwave Plastic?

Plastics breaking down is a matter of some concern because the chemicals that are released have been linked to “altered brain development, neurological and behavioral conditions, increased risk of metabolic diseases, increased risk of some cancers, altered fertility outcomes, altered thyroid hormones, and more,” Vandenberg says. 

Bottom line? Don’t microwave any plastic container, even if it says it’s microwave-safe. 

Equipment Review

The Best Glass Food Storage Containers

Sturdy, stain-proof, and microwavable, glass can be a good choice for food storage, but which container offers the best size, shape, and sealing power?
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What’s a Good Alternative to Plastic?

If you want to cut down on your plastic use, consider switching over to using glass food storage containers. While it’s hard to find models that are made completely of glass—often, the lids are made of plastic and/or silicone—you’ll be reducing your plastic use and exposure. And, of course, it is completely safe to microwave in any glass vessel.

Our favorite glass food storage container is the OXO Good Grips 8 Cup Smart Seal Rectangle Container; this line is available in a variety of different useful sizes, which we also recommend. 

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