What to Know About Recycling Styrofoam

Medically Reviewed by Poonam Sachdev on January 09, 2023

Polystyrene foam — known by most as Styrofoam — was widely introduced by Dow Chemical Company in the 1950s. Used to protect and insulate packed items like household products, food, and even donated organs, Styrofoam is prevalent and produces a lot of waste. Luckily, there are ways of recycling Styrofoam to keep it from ending up in landfills.

What Is Styrofoam Made Of?

Styrofoam is a type of solid plastic made from petroleum. Brand name Styrofoam was originally extruded polystyrene, but a derivative called expanded polystyrene or EPS is what is more commonly used today. EPS is made when pentane and steam are circulated through polystyrene beads, causing them to expand. As a result, EPS is over 90% air and incredibly lightweight.

Due to its wide use and popularity, the patented brand name "Styrofoam" is the term used to refer to any generic polystyrene foam products, including expanded polystyrene foam — like Kleenex for tissues and Band-Aids for bandages.

How Is Styrofoam Made?

To produce Styrofoam products, manufacturers put polystyrene through three stages. The first stage is the expansion stage, in which air is added to polystyrene beads. The beads are put into a machine called a profoamer. Inside the profoamer, steam circulates through the beads causing them to expand about 40 times their original size. A small amount of pentane gas is also added to the machine to further expand the beads.

In the second stage, the expanded beads mature for 12–24 hours. As the beads cool, the pentane inside them liquefies, creating a partial vacuum within the beads and allowing air to diffuse into them. 

Finally, the air-filled beads are molded into a desired shape. At this point, the beads are reheated with steam and poured into a mold where more steam is used to expand them another 10%. After this, extra water and heat are drawn out by a vacuum and the mold is left to cool.

Why Is Styrofoam Widely Used?

There are a variety of reasons companies prefer to use Styrofoam over other packing or insulation products:

  • It is very lightweight
  • It is non-toxic
  • It does not react with other elements
  • It does not grow bacteria or fungi
  • It is waterproof
  • It absorbs shock well
  • It is an effective insulator

This material is not just used in packaging, either. Styrofoam can be found in:

  • Appliances
  • Automotive parts including car seats
  • Electronics
  • Insulation

Is Styrofoam Bad for the Environment?

There are two main concerns when it comes to the environmental impact of Styrofoam: manufacturing effects and breakdown effects.

The manufacturing process of Styrofoam releases over 50 chemical byproducts into the atmosphere, depleting the ozone layer and creating hazardous waste. These chemicals include styrene, which is categorized by both the U.S. Department of Health and Human Services and the International Agency for Research on Cancer as "reasonably expected to cause human cancer". Exposure to styrene can also cause irritation of the skin, gastrointestinal tract, respiratory tract, and eyes. Long-term contact with styrene can result in more serious effects, including disrupted kidney function, depression, fatigue, weakness, headaches, and even hearing loss.

The other concern regards what happens when Styrofoam ends up in landfills. Styrofoam breaks down very slowly — it can take up to 500 years to fully decompose — and as it does, it leaches dangerous chemicals into the ground that contaminate the water supply and eventually end up in the atmosphere.  

To help combat environmental damage from this process, numerous cities across the U.S. have banned the use of Styrofoam in food service products, including:

  • Baltimore, Maryland
  • Freeport, Maine
  • Miami Beach, Florida
  • Minneapolis, Minnesota
  • Nantucket Town and County, Massachusetts
  • New York, New York
  • Portland, Maine
  • Portland, Oregon
  • San Francisco, California
  • Seattle, Washington
  • Takoma Park, Maryland
  • Washington, D.C.

Can You Recycle Styrofoam?

Most of the time, you cannot recycle Styrofoam in your recycling bin. Because Styrofoam is mostly air, the only way recycling plants can process it is by compacting it into a denser shape. To do this, recycling plants need to possess the right equipment, or they have to shoulder the cost of sending it somewhere that does. However, the cost and impact of transporting Styrofoam usually outweigh the potential environmental benefits of recycling it.

Luckily, there are still a few other things you can do with your styrofoam besides throwing it in the garbage.

How to Recycle Styrofoam

Although you usually cannot put Styrofoam in your recycling bin, it will still be stamped with the recycling symbol. Inside the recycling symbol is a number that tells you the type of plastic it is made of. Check with your local recycling service to see which types of plastic they accept. Most recycling services will take:

  • Plastic #1: Polyethylene terephthalate is the plastic used in drink bottles, food containers, and detergent containers.
  • Plastic #2: High-density polyethylene makes up containers like milk jugs, water jugs, and shampoo bottles.
  • Plastic #5: Polypropylene is found in items like yogurt and pudding cups. Not every recycling location will accept plastic #5.

Polystyrene — the plastic from which Styrofoam is derived — is categorized as plastic #6. If your local recycling center doesn’t accept this number, you cannot put it in your recycling bin. Instead, there are some other ways to safely dispose of your Styrofoam.

Find a recycling center that does accept Styrofoam. Your curbside recycling service may not take it, but there might be other recycling centers nearby that do. Go to to find Styrofoam recycling locations near you.

Sell it. Some companies will buy your Styrofoam so it does not end up in a landfill. You can find such companies by visiting the American Chemistry Council’s website

Turn it into glue. You can turn Styrofoam into glue just by adding a natural oil called d-limonene to it. D-limonene is a solvent made from citrus fruits, and when you put it on Styrofoam, it turns it into a sticky adhesive.

Though Styrofoam recycling may take a bit of time and effort, there are many options to consider to protect the environment from its harm.

Show Sources

Advanced Materials: "A High-Performance Recycling Solution for Polystyrene Achieved by the Synthesis of Renewable Poly(thioether) Networks Derived from D-Limonene."
British Plastics Federation: “Expanded Polystyrene.”
Chemical Safety Facts: “Polystyrene.”
Children’s Environmental Health Network: “FAQs: Polystyrene Foam.”
Communities for Recycling: “Is Styrofoam™ Recyclable?”
Minneapolis: “Accepted recycling.”
Plastics Markets: “Home.”
Public Broadcasting Services: “Smart Plastics Guide.”
Recycle Foam: “About Foam Recycling.”
Society of Environmental Journalists: "Styrofoam Facts — Why You May Want To Bring Your Own Cup."
Stanford Magazine: “What to Do with Styrofoam: Essential Answer.”
U.S. Department of Health and Human Services: “Report on Carcinogens, Fifteenth Edition.”

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