Microwaving Styrofoam Is Dangerous Because Of These Chemicals

Microwaving Styrofoam

Many people settle for using styrofoam containers because the material is convenient and lightweight.

It is also high in compression and protects fragile items when they are dropped or compressed.

Polystyrene, the primary ingredient in styrofoam, is also a strong insulator, ensuring the electrical charge rises.

Will microwaving styrofoam kill you? Polystyrene contains harmful compounds, such as styrene. It has potential carcinogens and neurotoxins that are detrimental to humans. Microwaving may cause this toxic chemical to reach out to your food. It may not kill you immediately, but it can harm you.

Some styrofoam can be microwave-safe, but I strongly discourage you from microwaving them.

This article will discuss the melting point and dangers of microwaving styrofoam.

The Chemicals in Styrofoam

Styrofoam is the trade name of polystyrene foam (petroleum-based plastic) components used in all types of styrofoam containers.

It is made of a styrene monomer and a lightweight substance consisting of around 95% air with strong insulating properties.

It is often used in shipping devices—to be more specific, computers and other fragile materials—to prevent any damage.

Microwaving Styrofoam

There is a controversy over whether or not polystyrene leaches chemicals into food as it is heated.

What Temperature Can You Heat Styrofoam?

The National Institute of Standards and Technology published several reports about microwaving styrofoam.

The reports suggest that polystyrene has begun to show signs of decomposition at about 200°C. They also say that trace quantities of polystyrene are seen.

At around 224°C, it begins to break down. The temperature is about 175 degrees for pure styrene.

You do not want to cook anything in styrofoam at these temperatures! You should know better than heating your food for convenience and later on suffer the consequences.

Does Styrofoam Melt?

Yes, it does melt in acetone and a microwave for an extended period or with excessively hot food or substances.

Styrofoam, consisting of expanded polystyrene, cannot withstand high temperatures.

It continues to weaken at 212°F and melt at 464°F. You may use styrofoam containers to store food in the refrigerator but never reheat or roast them in the oven.

Here are the dangers of microwaving styrofoam:

1. Fire

Pure polystyrene is extremely flammable, but chemical additions make it more flame-resistant depending on the application.

Unfortunately, styrofoam containers are small and are not meant to be heated. It means that this type of container still has a chance of catching fire.

2. Cancer

Polystyrene containers contain a substance called styrene, which has been linked to cancer.

Some evidence shows that it can cause cancer in humans. One can have elevated risks for lymphohematopoietic cancers, such as leukemia and lymphoma.

It can also cause genetic disruption in white blood cells or lymphocytes.

Other potential dangers when microwaving styrofoam:

  • Eye and stomach irritation
  • Headaches
  • Hearing loss
  • Clinical depression
  • Dysfunction of the central nervous system
  • Fatigue


If there is doubt, throw away the styrofoam. Do not microwave styrofoam products until you see a symbol that they are microwave-safe.

Even so, the danger still outweighs the benefits. Instead of using plastics or styrofoam to reheat meals, try something more environmentally friendly like reusable glass and ceramic.

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