According to the U.S. Environmental Protection Agency (EPA), recycling has three steps: collection, processing, and remanufacturing. EPA, The U.S. Recycling System (Oct. 25, 2023). Recycling is the second most preferred action on EPA’s Nonhazardous Materials and Waste Management Hierarchy, behind source reduction and before energy recovery. U.S. EPA, Sustainable Materials Management: Non-Hazardous Materials and Waste Management Hierarchy (June 19, 2023). Many materials are collected for recycling—paper, aluminum, glass, organic matter, and plastic—but recycling rates differ. Paper, for example, has a recycling rate of 68%, while plastic has the lowest recycling rate: 8.6%. EPA, Facts and Figures About Materials, Waste and Recycling (Nov. 22, 2023). This number has led reporters and researchers to call the U.S. plastic recycling system broken. Renne Choo, Recycling in the U.S. Is Broken. How Do We Fix It?, Colum. Climate Sch. (Mar. 13, 2020).
Despite these unimpressive numbers, recycling receives support from legislatures and the public. Nation-states and the international community have included recycling in plastic pollution treaty drafts and negotiations. EPA recently announced its largest investment in recycling in 30 years. Press Release, EPA, Biden-Harris Administration Invests More Than $100 Million in Recycling Infrastructure Projects Through Investing in America Agenda (Sept. 13, 2023).
But the problem with plastic recycling specifically lies not in the process, but in the material. Plastic’s chemical composition explains its low recycling rate as compared to other materials. Paper, aluminum, and glass are, for the most part, homogenous materials, made up of compounds from cellulose (paper), aluminum ores, and silicon dioxide (glass). Plastic, in contrast, is made up of thousands of different polymers and chemicals, making recycling nearly impossible. UN Env’t Programme (UNEP), Chemicals in Plastics: A Technical Report (2023). The codes for the different plastic polymers often appear as printed numbers on plastic. But these numbers (1–7) are resin identification codes (RIC), rather than symbols of recyclability.
Mechanical Recycling
In theory, plastic recycling rates would increase if the feedstock to be recycled were all made up of the same polymer. For example, it is possible to recycle the plastic found in plastic water bottles, PET #1 (polyethylene terephthalate), from post-use plastic bottles into new plastic bottles. This happens through the process of mechanical recycling, where the plastic is washed, shredded, melted down, and turned into small pellets. During this process, the chemical structure of the plastic is not significantly changed, though some degradation does occur such that plastic bottles are not indefinitely recyclable.
In practice, however, plastics are mixed, and plastics of all RICs—bottles, containers, bags, and packaging—make their way into blue recycling bins. Because of their different chemical compositions, mixed plastics, and diverse categories of plastic, like the hodgepodge of polymers in the catchall plastic #7 including synthetic fabrics, cannot be mechanically recycled into anything useful. One study using XRF spectrometry found that in 19 PET bottles and 17 polyethylene caps, the composition and concentration of metallic and halogen elements varied—a reflection of different manufacturing decisions about the use of catalysts, pigments, and flame retardants. This variability, while expected in plastics, is not regulated by EPA. As the authors note, the presence and complexity of chemicals used in plastics are “impediments to recycling.” Montserrat Filella & Andrew Turner, Towards the Global plastic Treaty: A Clue to the Complexity of Plastics in Practice, Env’t Sci. Europe (Nov. 15, 2023). Because of the variation in plastic polymers, those plastics that are recycled are usually “downcycled” and incorporated into other products like asphalt. Thus, the inherent heterogeneity of plastics impedes recyclability, and most plastics are fundamentally unrecyclable.
Chemical Recycling
As an alternative to mechanical recycling, some plastic companies are promoting chemical recycling or advanced recycling to tackle plastic waste. Chemical recycling relies on heat, pressure, and solvents to process the plastic. It differs from mechanical recycling in that the plastic lattice structure is dissolved and the long polymer chains found in plastic are broken into monomers. Some types of chemical recycling utilize thermal processes to produce basic molecules in liquid or gas forms. The end monomer products can then be processed into new polymers and plastics while the end basic molecules can be processed into fuels, oils, waxes, new plastics, or other chemical products. UNEP, Chemicals in Plastic, supra.
While this technology sounds promising, there is no evidence that chemical recycling is environmentally or economically better than mechanical recycling. For example, a 2023 study conducted by the American Chemical Society (ACS) compared mechanical recycling to chemical recycling and found that two kinds of chemical recycling—methanolysis and dissolution—had worse metrics than mechanical recycling when it came to greenhouse gas emissions, toxicity, land use, and water use. Taylor Uekert et al., Technical, Economic, and Environmental Comparison of Closed-Loop Recycling Technologies for Common Plastics, ACS Sustainable Chemistry & Eng’g (Jan. 12, 2023). Additionally, chemical recycling technology is still being developed; there are no large-scale, sophisticated recycling plants that produce high-quality recycled material through chemical recycling in the United States.
Finally, using the term “recycling” to describe these processes is misleading. EPA’s 2020 Draft Recycling Strategy explains that the term “recycling” refers to mechanical recycling; there is no mention of chemical recycling. EPA, Draft National Recycling Strategy (Oct. 5, 2020). More importantly, however, using heat to convert plastic to fuel is an energy recovery process, not a recycling process. Further indication that chemical recycling by pyrolysis is incineration rather than recycling is EPA’s proposal to reclassify plastic pyrolysis and related combustion units as a municipal waste combustion unit under the other solid waste incineration New Source Performance Standards of the Clean Air Act. EPA, Proposed rule, 88 Fed. Reg. 36,524 (June 5, 2023) (to be codified at 40 C.F.R. pt. 60). Thus, chemical recycling processes are a less preferred outcome when considering EPA’s waste management hierarchy.
State Approaches to Recycling
As discussions around plastic pollution and recycling have become commonplace, two approaches have emerged in state legislatures. A minority of states have enacted some form of extended producibility responsibility (EPR) legislation for plastic. With a focus on mechanical recycling, the goals of such legislation are to incentivize increased recyclability, promote higher recycling rates, and enhance the accountability of those who produce and use plastic. Ultimately, these laws put the manufacturer rather than the municipality or individual on the hook for the plastic waste generated. In contrast, 25 states have passed legislation that recognizes advanced recycling as a manufacturing rather than waste management practice. This reclassification provides tax benefits and offers fewer environmental restrictions.
Regardless of the process and whether it is considered recycling or something different, virgin plastics continue to be cheaper to produce than recycled plastics, making it hard for recycling processes to compete.
Problems with Plastic Recycling
Mechanical and chemical recycling are different processes, with different environmental impacts. Neither can eliminate all our plastic waste.
First, recycling only addresses post-use plastic that is captured and collected. Even though almost all Americans support recycling, only about 32% do recycle, which means that most plastic ends up landfilled. EPA, Facts and Figures About Materials, Waste and Recycling, supra. Recycling as a solution to plastic waste also ignores the most problematic plastics: microplastics. Most plastics shed microplastics, and the planet is saturated with microplastics from ubiquitous sources. Plastics from tires, synthetic fabrics, and coatings are too small to be captured and will never be recycled.
Second, even if all the plastic in the world were captured, not all plastics are capable of being recycled. Contrary to the public’s understanding, the chasing arrows triangle that is found on many plastic products does not mean that that product is recyclable. The resin identification code on plastic products reflects the resin used in the product and does not mean that the plastic can be reclaimed or that there is a market for that kind of recycled plastic. So much confusion exists around the recycling symbol and resin codes that EPA requested that the Federal Trade Commission (FTC) revise its Green Guides to clarify the meaning of these symbols and codes. Letter from Jennie Romer, Deputy Assistant Adm’r for Pollution Prevention, EPA, to Fed. Trade Comm’n, Comment re Green Guides Review, Matter No. P954501 (Apr. 20, 2023).
Finally, even if all plastics were capable of being recycled, low demand for recycled plastics further disincentivizes the creation of a market for recycled plastics.
Recycling Plastics Releases Microplastics and Other Pollutants
The recycling processes discussed above also release microplastics, as well as other harmful substances, into the environment. The mechanical process of collecting, loading, transporting, unloading, washing, and shredding, all in preparation for recycling, releases significant amounts of microplastic before recycling can even begin. Even when filtration systems are installed, microplastics can escape. A 2023 study found microplastics in the wastewater of a state-of-the-art recycling facility, equipped with a filtration system. Erina Brown et al., The Potential for a Plastic Recycling Facility to Release Microplastic Pollution and Possible Filtration Remediation Effectiveness, 10 J. Hazardous Materials Advances 100309 (2023). High quantities of microplastics were also found in the air surrounding the facility. Additionally, polyfluoroalkyl substances (PFAS) and other chemical additives from plastic packaging are released in wastewater when plastic is washed. Finally, some chemical recycling processes described above rely on hazardous solvents and generate hazardous air pollutants and hazardous waste.
Recycling Plastic Harms Marginalized Communities in the United States and Abroad
The plastic waste generated in the United States needs someplace to go. Because plastic is not readily recycled in the United States, plastic not landfilled or burned is shipped overseas, disposed of in marginalized communities, or simply abandoned, foisting the chemical risks and air and water pollution associated with end-use plastic onto developing countries. Beth Gardiner, Indonesia Cracks Down on the Scourge of Imported Plastic Waste, Yale360 (Aug. 1, 2023). Before 2018, much of the plastic waste generated in the United States was sent to China—a willing trade partner. However, China’s 2017 policy banning plastic waste from the United States forced the United States to find new trade partners in Asia, Africa, and Mexico. Under the Basel Convention, some of these countries require prior informed consent before receiving hazardous wastes, which now include plastic, but countries have found ways to skirt these requirements. Finally, within the United States, EPA has recognized the environmental justice issues that arise from plastic and recently noted that “disadvantaged communities . . . experience disproportionate burdens from [plastic] production and waste management processes” in its April 2023 Draft National Strategy to Prevent Plastic Pollution, from the Office of Resources Conservation and Recovery (EPA 530-R-23-006).
Prioritizing Plastic Source Reduction
While well-intentioned, efforts that focus on recycling as the solution to our plastic problem fall short. Both mechanical and chemical recycling impact our air and water quality, and these processes should not be used to justify the production of more plastic, nor should other countries bear the brunt of dealing with plastic waste. We should prioritize policies that focus on source reduction, the most environmentally preferred strategy, because we will never be able to recycle our way out of our plastic problem.
