You cannot microwave food or liquids in polystyrene containers unless they are marked “microwave safe,” but you can do so with Styrofoam containers if they bear the microwave-safe label.

This article discusses the pros and cons of microwave-ing Styrofoam, as well as safety measures you can take.

What is Styrofoam?

Styrofoam is a term that’s trademarked by The Dow Chemical Company. It refers to a type of polystyrene foam that’s commonly used in the building industry.

A type of expanded polystyrene foam that is injected into molds to produce disposable take-out containers, plates, coffee cups, and packaging peanuts is what the term incorrectly refers to in some nations, such as the United States and Canada.

These containers are well-liked because they are affordable and function well as insulators, keeping food and liquids warm.

Although polystyrene containers were widely used in the past, they have gradually been outlawed in several American cities, including San Francisco and Seattle, because of potential health risks and environmental issues.

Environmentally, the containers do not decompose easily and are difficult to recycle. Additionally, animals might mistake them for food and eat them.

Styrene, a substance found in them that has been linked to cancer in both animal and human studies, has caused some concern from a health standpoint.

Traditional Styrofoam

It is not safe to microwave this most-common type of Styrofoam. The substance is stable during typical use. But at high temperatures, it begins to melt or break down. A microwave oven may cause the toxic chemical styrene (among other chemicals) to leach into your food even if there is no obvious damage to the foam. Your health and reproductive system may be at risk from the potential carcinogen styrene.

Microwave-safe Styrofoam

The FDA has approved a less popular variety of Styrofoam as microwave-safe. This alternative material is constructed with safer materials and lower levels of hazardous chemical compounds, and it has greater stability when heated.

How can you tell if Styrofoam is microwave-safe? Check the packaging for a clear label. It’s ultimately up to you whether you want to microwave this unique kind of Styrofoam or stay completely safe. However, after taking it out of the microwave, if you notice any obvious signs of damage to the Styrofoam, throw both the food and the container away. Additionally, don’t microwave it if the foam has cracks or if you’ve already microwaved it once.

Can You Microwave Styrofoam?

Polystyrene foam containers should not be microwaved, according to some.

They contain a substance called styrene, which has been connected to cancer in studies on both humans and animals. This is a major factor.

Additionally, chemicals used in manufacturing may leak into food when it is microwaved in polystyrene or plastic containers. This is especially true of fatty foods like cheese and meat.

It’s crucial to remember that the Food and Drug Administration (FDA) controls and tests the safety of plastic and polystyrene dishes, cups, and containers as well as their use in microwaves.

The products made of polystyrene or plastic that bear the microwave-safe label have undergone microwave safety testing.

Contrarily, you should avoid microwaving food in polystyrene containers that are not marked as microwave safe because their safety cannot be guaranteed. This safety measure holds true for all types of heating, not just microwaves.

Safe Ways to Heat Food in the Microwave

The good news is that using different methods than the microwave to reheat food will help you avoid chemical exposure, according to Halden.

Instead of reheating food inside an EPS container, Halden recommends transferring food or drinks to a microwave-safe container made of glass. The FDA also lists ceramic and plastic as suitable materials for microwaving.

To find out if your container can be microwaved, look for a microwave-safe symbol on the bottom. Typically, a microwave with wavy lines will be used.

The Bottom Line

Because their safety cannot be guaranteed, never microwave polystyrene containers that do not bear a microwave-safe label.

This is due to the presence of the substance styrene, which has been connected to cancer, in polystyrene containers.

However, packaging bearing a microwave-safe label has undergone testing and is not expected to present any styrene-related hazards.

Transferring your food into a ceramic, glass, or pyrex container before heating it can help ease any worries you might have.

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