Plastic bags are recycled through a multi-step mechanical process that shreds them into small flakes, washes away contaminants, and melts the clean material into pellets that manufacturers can use to make new products. But here’s the catch: only about 10% of plastic bags, sacks, and wraps generated in the United States actually get recycled. The rest, roughly 3 million tons per year, end up in landfills. A big reason for that gap is that plastic bags can’t go in your curbside recycling bin. They require a completely separate collection system.
Why Plastic Bags Can’t Go in Curbside Bins
Recycling facilities that process your curbside bin use spinning discs, rollers, and conveyor belts to sort materials automatically. Plastic bags are thin, stretchy, and lightweight, which makes them what the industry calls “tanglers.” They wrap around equipment, jam the machinery, and force workers to stop the line and cut them out by hand. This is slow, dangerous, and expensive. A single bag caught in a disc screen can shut down sorting for minutes while a worker removes it with a blade.
Because of this, nearly every municipal recycling program in the country asks you to keep plastic bags out of your bin. Tossing them in doesn’t just mean they won’t get recycled. It actively disrupts the recycling of everything else in that load.
Where to Drop Off Plastic Bags Instead
Most grocery stores and large retailers have collection bins near their entrances specifically for plastic film. These bins accept more than just grocery bags. You can typically include bread bags, dry cleaning bags, bubble wrap, newspaper sleeves, and the outer wrapping from cases of bottled water or paper towels. All of it needs to be clean, dry, and free of food residue.
A quick way to test whether a piece of plastic film belongs in the bin: try stretching it. If it stretches, it’s likely recyclable. If it tears like paper or makes a crinkly, crunchy sound when you squeeze it, leave it out. That crinkly texture usually means the film contains layers of different materials bonded together, which contaminates the recycling stream.
Items that look similar but don’t belong include frozen food bags, chip bags, candy wrappers, pet food bags, mesh produce bags, and pre-washed salad bags. These are made from mixed materials or different plastic types that can’t be processed alongside standard polyethylene film.
The Types of Plastic in Bags
Most plastic bags are made from one of two closely related materials. Grocery and retail bags are typically high-density polyethylene (resin code #2), while produce bags, bread bags, and food storage bags are usually low-density polyethylene (resin code #4). Both are part of the polyethylene family, and recyclers can process them together. This compatibility is what makes store drop-off programs work: everything collected in those bins is essentially the same type of plastic in slightly different forms.
How the Recycling Process Works
Once collected, plastic bags are compressed into large bales and shipped to a reclaimer, which is the facility that does the actual recycling. The process follows a consistent sequence of steps.
First, workers cut open the bales and spread the material onto a conveyor belt. Even though the bags were pre-sorted at collection, the material goes through another round of sorting to pull out contaminants like bits of glass, metal, or non-polyethylene plastics. Material gets separated into three categories: the target plastic (high value), missorted plastics that can be sold to other recyclers (medium value), and waste.
The sorted film then feeds into an industrial grinder that cuts it into small pieces called flake. These flakes move into a washing stage where hot water and detergent dissolve surface dirt and any adhesives from labels. After washing, the flakes enter a large water tank. Different types of plastic have different densities, so some float and some sink. This float/sink separation catches any remaining non-polyethylene material that made it through earlier sorting.
The separated flakes get rinsed again, then air-dried. Next comes a step called elutriation: the flakes pass through an airstream that blows away any thin layers of non-plastic material. Some packaging uses ultra-thin layers of other materials to extend shelf life, and these layers can peel off during washing. The air separation catches those loose fragments before they contaminate the final product.
If the recycled plastic will be used in food-contact packaging, it goes through an additional decontamination step using heat and vacuum under low-oxygen conditions. Finally, the clean flakes are fed into an extruder, which melts them, pushes the molten plastic through filters to catch any remaining solid particles, and forms the material into uniform pellets. These pellets are the finished product that gets sold to manufacturers.
What Recycled Bags Become
Recycled polyethylene pellets from bag collection programs go into a range of products. One of the most common is composite lumber, the material used for outdoor decking, park benches, and playground equipment. Pellets also become new plastic bags, trash can liners, shipping envelopes, and agricultural film. The quality of the recycled pellet determines what it can be used for. Cleaner, more uniform feedstock produces pellets suitable for new film products, while lower-grade material goes into lumber or other applications where some inconsistency in the plastic doesn’t matter.
Why the Recycling Rate Is So Low
Of the 4.2 million tons of plastic bags, sacks, and wraps generated in 2018 (the most recent EPA data available), only 420,000 tons were recycled. That 10% rate comes down to several compounding problems.
The biggest is convenience. Curbside recycling is easy because it happens at your door. Store drop-off requires a separate trip or at least remembering to bring a bag of bags with you when you shop. Most people don’t bother. Contamination is another barrier. Bags with food residue, moisture, or mixed materials get rejected. And because plastic film is so lightweight, even a large volume of bags doesn’t represent much material by weight, making it less economically attractive for recyclers compared to heavier plastics like bottles and containers.
Mechanical recycling also has inherent limits. Each time plastic is melted and reformed, the polymer chains shorten slightly, which degrades the material’s strength and flexibility. This means recycled polyethylene can only go through the process a limited number of times before the quality drops too far for useful applications. The process also requires relatively clean, well-sorted material. Mixed or contaminated plastic can’t be mechanically recycled effectively.
Chemical Recycling as an Alternative
Chemical recycling takes a fundamentally different approach. Instead of melting plastic and reshaping it, these processes break the polymer chains down into simpler chemical building blocks, which can then be reassembled into new plastic or converted into fuel. Pyrolysis, the most common method, heats plastic in an oxygen-free environment to break it down into oils and waxes.
The advantage for plastic bags specifically is that chemical recycling can handle mixed, contaminated, and multilayer materials that mechanical recycling can’t. Films that would be rejected from a mechanical recycling stream because they contain layers of different plastics bonded together can potentially be processed through pyrolysis. The technology is still scaling up and remains more expensive than mechanical recycling, but it addresses some of the core reasons so much plastic film currently ends up in landfills.