Number 6 plastic, also known as polystyrene (PS), is technically recyclable but almost never accepted in curbside recycling programs. The foam version, commonly called Styrofoam, is particularly difficult to recycle because it is roughly 95% air, making it extremely costly to collect and transport relative to its material value. If you put it in your curbside bin, it will likely be treated as a contaminant and could cause an entire load of recyclables to be rejected.
Rigid vs. Foam: Two Types of #6 Plastic
Not all #6 plastic is the same. Rigid polystyrene is the smooth, glossy version found in plastic cutlery, CD cases, party cups, and coffee cup lids. Expanded polystyrene (EPS) is the lightweight foam version used for takeout containers, meat trays, egg cartons, packing peanuts, and protective packaging around electronics. Both carry the #6 recycling symbol, but they behave very differently in the recycling stream.
Rigid #6 has slightly better odds of being accepted by some recycling programs, though it’s still uncommon. Foam #6 is the real problem. Its bulk, fragility, and tendency to absorb food residue make it one of the most difficult consumer plastics to recycle at scale.
Why Most Programs Reject Foam #6
The core issue is economics. A full truckload of loose EPS foam is still 95% air. The cost of transporting that truck often exceeds the value of the recovered material. Recycling only becomes efficient when foam is ground up and then compacted into a much denser form, a process called densification. Most municipal recycling facilities simply don’t have the specialized equipment to do this.
Food contamination compounds the problem. Polystyrene’s chemical structure attracts oils and grease, pulling nonpolar molecules deep into its polymer chains. Once food residue gets absorbed, it’s nearly impossible to clean. A used foam takeout container can weigh more from trapped food residue than from the plastic itself. The recycling industry recommends against densifying contaminated foam because the compaction process locks in the residue, making the resulting material unusable. Municipalities that have tried accepting foam in curbside collection found it compacts in garbage trucks, breaks into small pieces, and arrives at sorting facilities covered in food waste, essentially worthless.
When foam does end up in your recycling bin, it doesn’t just get ignored. It becomes a contaminant that can cause problems for the entire batch. Bits of foam cling to paper and cardboard, degrade sorting equipment, and can lead recycling facilities to reject whole loads of otherwise good material.
How Polystyrene Recycling Actually Works
When #6 foam is successfully recycled, the process starts by feeding collected EPS through a shredder that breaks it into small pieces. Those pieces then move into a foam densifier, which uses heat and pressure to melt the material into a thick paste. The paste is extruded through a narrow outlet and cooled into solid blocks called ingots. This process can reduce the foam to as little as 1/90th of its original volume, and it produces no emissions.
Those ingots can then be used as raw material for new products like picture frames, crown molding, or rigid plastic items. The catch is that very few facilities in the country perform this process, and they need a steady supply of clean, uncontaminated foam to make it work.
How to Recycle #6 Foam If You Want To
Your best option is to search for a specialized drop-off location near you. Earth911’s recycling search tool (earth911.com) lets you enter “polystyrene” or “Styrofoam” along with your zip code to find nearby facilities. You can also call 1-800-CLEANUP for local recycling information. Some shipping and packaging stores will accept clean packing peanuts and foam blocks for reuse.
The key word is “clean.” Any foam that has touched food, especially greasy or oily food, is essentially unrecyclable. Clean packaging foam, protective inserts from electronics boxes, and unused packing peanuts are your best candidates. Rinse and dry any foam that had minimal food contact before dropping it off.
Growing Bans on Foam Containers
Several states and cities have decided the recycling challenge isn’t worth solving and have banned foam food containers outright. New York State adopted what it called the nation’s strongest state ban on expanded polystyrene in 2020, prohibiting single-use foam food and beverage containers and packing peanuts starting January 1, 2022. Cold storage foam containers face a ban starting January 1, 2026. New York City has its own local polystyrene ban as well.
Other states including Maine, Maryland, and Virginia have enacted similar restrictions, and dozens of cities across the country have local bans in place. The trend is moving toward eliminating foam food containers rather than trying to make them recyclable.
Health Concerns With Foam Food Containers
Beyond the recycling question, there are reasons to limit your use of foam containers regardless. Polystyrene is manufactured from styrene, a volatile liquid compound that studies have linked to genetic damage in white blood cells and certain blood cancers. In its solid state, polystyrene is considered safe for food contact. But heating causes chemicals to leach from the foam into whatever food or drink is inside.
A single exposure from a melted or overheated foam container is unlikely to cause harm. The concern is cumulative: repeated use of foam containers for hot foods and beverages adds up over time. If you regularly eat takeout from foam containers, transferring hot food to a plate or glass before eating is a simple way to reduce exposure. Never microwave food in a polystyrene container.