Is It Dangerous To Put Styrofoam In The Oven?

It's unavoidable to have days when you just have to order takeout to get a proper meal. In instances when you receive your food ahead of mealtime, double-check first if your takeout container is made of Styrofoam before heating it up — and if it indicates that it is microwave-safe.

Styrofoam is the trademarked name given to polystyrene, a solid plastic material that's commonly used to make disposable food and beverage containers and utensils. Since it's foamed with carbon dioxide gas, polystyrene is able to insulate its contents, thus its popularity as a material for food packaging. However, it's also a highly flammable material that softens when placed in an environment with a temperature of 212 degrees Fahrenheit; at 464 degrees Fahrenheit, it starts to melt. Since reheating food in the oven requires at least 325 degrees Fahrenheit to be safe, as advised by the University of Illinois Extension, you definitely should not place your takeout meal in there while it is still in a Styrofoam container.

The microwave might be a safer place for this material, provided that the container indicates that it's microwave-safe. Sometimes, this is spelled out at the bottom of the container. Other times, the container simply features a logo of three wavy lines on top of each other. Looking for this sign is crucial since heating non-microwave-safe Styrofoam in the microwave will cause it to leak styrene, a compound that has been listed as a possible human carcinogen by the International Agency for Research on Cancer.

Transfer your food to a microwave-safe ceramic or glass container instead

Even microwave-safe Styrofoam containers must be heated with caution. Follow the directions given on their labels in order to warm your food safely. If the container already has visible damages like cracks and scratches or emits an unpleasant odor, it may be too old to use or is no longer safe to heat in the microwave. The best way to ensure that you don't contaminate your food as you warm it up again is to place it instead in a microwave-safe ceramic or glass container.

Ideally, you should consume hot food soon after it is cooked, or at least within two hours if you're leaving it out at room temperature. However, if you know beforehand that your takeout meal has to wait for a while, you can keep it hot, rather than stashing it in the refrigerator and taking it out later for reheating. To do this, preheat the oven to 200 to 250 degrees Fahrenheit (or use the "warm" setting, if it has one) so you can store the food in there. Transfer the meal from the takeout container into an oven-safe dish and cover it with aluminum foil before placing it in the oven so it doesn't dry out. Once you're ready to eat, use a food thermometer to check that your meal's temperature is at least 140 degrees Fahrenheit. That way, you're certain that it hasn't been hanging out in the danger zone.