Is Number 6 Styrofoam Microwave Safe? (Read This First!)

Categorized as Microwave Safety
Is Number 6 Styrofoam Microwave Safe?

Microwaveable containers are a staple in most kitchens. Using them is a quick and easy way to reheat leftovers or cook something quickly.

One of the most common types is styrofoam; it is cheap, durable, and perfect for microwaving food because it is lightweight and won’t break like ceramic or glassware might.

But “is number 6 styrofoam microwave safe?” is a question that consumers often ask. It’s important to know before you make your next purchase! This article will help you answer that question and more about this popular type of container so you can decide whether or not it is right for your kitchen needs.

Can You Microwave Styrofoam (Plastic Number 6)?

Although styrofoam is an FDA-approved food-grade material, it is not safe to put it in the microwave oven. Styrofoam does break down and has been shown to leach harmful chemicals, such as styrene, into food if exposed to heat.

What does plastic number 6 mean?  It is a code that is used to identify the type of plastic, which is polystyrene foam or commonly known as styrofoam.

Number 6 plastic used to be a popular choice for many packaging needs (including food packaging) because it is lightweight, inexpensive, and doesn’t break easily.

These include egg cartons, food containers, takeout containers, drinking cups, and more.

However, recently there is a concern about the chemicals that styrofoam is known to leach and it is no longer recommended for use as containers.

Therefore, many states have outlawed the use of styrofoam container in food packaging.  For example, here are some states that have banned Styrofoam containers: California, Connecticut, Delaware, Hawaii, New York (1).

Is There a Microwave Safe Styrofoam?

Does this mean all styrofoams can’t be microwaved?  No, you can microwave foods or beverages in styrofoam containers that have a microwave-safe label.

You can usually find this microwave-safe label on the bottom of all microwave-safe containers. Unlike traditional styrofoam, these types of styrofoam have been tested for microwave use.

Still, even though microwaving styrofoam labeled as microwave-safe is deemed safe, I would still recommend using other types of containers that are not made with styrofoam.

Glass or ceramic is a good option, these containers are able to withstand heat better than any styrofoam cup can do and are guaranteed won’t leach any dangerous chemicals into your food.

What Are Other Plastics Not Microwave Safe?

We all have microwaves in our homes. We use them for everything from making popcorn to reheating leftovers but are you aware other than styrofoam, there are other containers that are not microwave-safe.

Here is a list of containers you should never put in the microwave:

  • Plastic #1 Polyethylene Terephthalate (PET)
  • Plastic #3 PVC (polyvinyl chloride)
  • Plastic #7 polycarbonate

Plastic #1: Polyethylene Terephthalate (PET)

Plastic #1 Polyethylene Terephthalate (PET) is a type of plastic that is used in the manufacturing of many plastic items.

It is an FDA-approved food-grade plastic that is safe for contact with foods and beverages and has been used especially for packaging convenient-sized drink and food containers such as salad dressing, soft drinks, juice, and water. It’s also a popular packaging for peanut butter and cooking oil.

It is important to note that PET cannot be microwaved because it has a temperature tolerance of only 120 degrees Fahrenheit.

Plastic #3: PVC (polyvinyl chloride)

PVC is very dangerous and one of the least recyclable plastic in the market. Still, despite its dangerous properties, it has been used in many different types of packaging.

You can usually find PVC in cleaner bottles, cooking oil bottles, clear food wrap, shower curtains, and door frames. In the US, the FDA has approved the use of PVC for food contact applications.

However, you should know that PVC must not be used for heating or reheating food in microwave ovens as it is known as a potential carcinogen that can leach into your food as it is being reheated.

Plastic #7 polycarbonate

Polycarbonate is a very strong type of plastic that is hard to recycle and contains highly dangerous BPA (bisphenol-A) chemicals.

It can be found in many different types of products like toys, water bottles, sports equipment, car parts, and medical equipment. Try to avoid using products that contain polycarbonate as much as possible.

Which Plastic Is Safe to Microwave?

Plastic number 5 (polypropylene) is a good example of a plastic that can be safely microwaved.

It can withstand high temperatures and stays clear even when exposed to tomato sauce or types of sauce like BBQ sauce. It is also one of the most recyclable plastics around.

Nevertheless, remember that the number 5 just means the type of plastic will not be deformed when heated in a microwave oven. It doesn’t mean there are no chemicals leaching into your food when you use this number 5 plastic.

Some studies have shown that even microwaveable safe plastics can cause asthma or disrupt the endocrine system which is responsible for hormone production in the human body.

So, in my opinion, regardless of the type of plastic you use to heat your food in a microwave, it’s better to substitute them with glass or ceramic containers.

How to safely heat food?

There are many different ways to heat food. But people often use the microwave because it is quick and convenient. However, there is some debate about whether or not microwaves are safe for food containers made of Styrofoam materials.

If you’re concerned about the safety of microwave styrofoam containers, here are some tips to help you heat your food safely:

  1. Check the microwave-safe label. If you’re using a microwave-safe container made of Styrofoam, check for a label that says it is microwave safe. If it doesn’t have one, transfer the food to another microwave-safe container before microwaving.
  2. Use the stove or an oven. A far better option is to use your oven or stove to heat food, which heats the food uniformly and generates less risk compared to microwaving styrofoam containers. You can use a pot, van, or baking tray as a container.
  3. If you still insist to heat food in the microwave using a styrofoam container, start with low power and add time gradually. Don’t heat it for more than two minutes at a time and add 30 seconds each time.
  4. Vent the container. If you’re using a styrofoam cup, make sure you vent it first to avoid a buildup of pressure that can cause the cup to explode.
  5. Check for scratches or cracks. Scratches in the container can be signs of weakening, which can cause harmful chemicals to leach into your food. At this point, you should not use the container for microwaving anymore. To protect your health, avoid using scratched containers.

Final Thoughts

The answer to this question is not a simple yes or no. Some people are under the impression that Styrofoam cups and containers can be used in the microwave as long as they are unmelted, but there have been reports of these items causing health complications for some people.

If you want to use number 6 for reheating purposes, make sure there is a microwave-safe label and vent the cup/container before heating food. Also, try it out at a low power first to check for safety.

Just remember that there is still some risk of toxins entering your food so you should avoid using Styrofoam altogether if possible. Alternatively, consider using glassware instead since they don’t pose such a risk factor (and come with other benefits).

By Rosie Elliott

I’m Rosie. I’m a professional chef with experience in Western, Mediterranean, and Italian cuisine. I’ve been cooking for over 15 years, and I have two daughters that keep me busy!