What Happens to Styrofoam in a Microwave?

Styrofoam
1. Styrofoam is the commonly known brand name for a type of molded plastic foam called polystyrene. Many types of items are made from Styrofoam, including plates, cups and packing materials. Styrofoam is solid when at room temperature but will melt when exposed to heat. The plastic returns to a solid state after it cools.
Microwave Safety
2. Critics say that heating Styrofoam releases toxins that can cause illness and ruin food. However, the majority of scientists say this is not the case. Many varieties of Styrofoam are safe to microwave, and these products should have a "microwave-safe" label stamped somewhere on them. As with all dishes and food containers, look for that stamp before placing an object in the microwave. For example, the majority of Styrofoam takeout containers from restaurants are not microwave-safe.
Styrofoam in the Microwave
3. The heat from a microwave can cause a reaction in the Styrofoam plastic. Styrofoam's melting point is lower than the boiling point of liquids. This means that when Styrofoam that is not microwave-safe is microwaved, it will most likely melt. Melted Styrofoam will ruin any food or drink that it may contain and will also create a mess in the microwave. For this reason, Styrofoam that isn't labeled as microwave-safe shouldn't be heated in the microwave. Always keep an eye on Styrofoam containers while they're in the microwave and shut off the heat if they appear to be melting.