You put stuff out for recycling. What happens next might surprise you.

Recycling is one of the most recognized forms of environmental conservation in the United States. But differing standards for curbside recycling programs across the country and changes in the recycling industry can confuse consumers: What really happens after they toss items into a blue or green bin?

Before and during World War II, informal recycling was a standard practice – people used rags to make paper and collected scrap metal for military use. After the war, disposable goods became more popular, and items started to pile up in landfills. In 1970, an architecture student designed the now-iconic recycling symbol with three arrows representing the need to reduce, reuse, and recycle. 

The practice of recycling was spurred along by activist efforts, including the rise of curbside recycling in the 1990s, and the portion of waste that was recycled or composted in the U.S. shot up from 6% in 1960 to 32% in 2018, the most recent year government data is available. Here we examine what to know about the recycling process and how effective it is. 

What exactly happens to items put out for recycling?

Most loads of recycling in the U.S. are sent to what are known as materials recovery facilities to be processed and sorted. Workers comb through many of the materials by hand, separating out different material types and discarding anything that can’t be recycled. Technology also helps with sorting – for example, some recycling facilities use a large magnet that sucks metal off a conveyor belt. 

What happens to the recycled products after they’re sorted depends on the material. Glass, aluminum, and steel are 100% recyclable, meaning they can be turned into new products indefinitely if they’re not contaminated. Most glass is made into new glass bottles and jars, while metals can be used in car or airplane parts. Paper and cardboard are the most commonly recycled items, and can be repurposed into a variety of products, including cereal boxes, tissues, and egg cartons. However, their recycling value is also limited: Paper can be recycled only five to seven times before it becomes too degraded.  

Because the U.S. doesn’t have a centralized recycling system, recycling facilities in different communities have distinct standards for operation – which can mean that they don’t all accept the same materials. Most municipalities will publish specific guidance on which items are accepted in their community. Items such as paper sheets, aluminum cans, and cardboard are virtually always recyclable, while acceptability varies by location for plastics, glass, and some specific items such as shredded paper and scrap metal. 

Do items tossed into a recycling bin always get recycled?

Consumer mistakes can hinder the process. Contamination happens when someone tosses an item that is either nonrecyclable, like a garden hose, or too damaged for proper recycling, like a dirty pizza box, into a recycling bin. This contamination can slow down the sorting process and make it more expensive. 

“Contamination is probably the single biggest problem at recycling centers, because if you have a lot of contamination in your stream of recycled material, that really depresses the value of anything you can sell at the other end,” says Jordan Howell, an associate professor at Rowan University in New Jersey who researches sustainable business practices.

Contamination is especially a problem with “single-stream” recycling, a system wherein all recycled items are tossed into the same container instead of being separated into plastics, paper, metal, etc. Single-stream recycling is the most common recycling method and was designed to make recycling easier for consumers. But it also increases the likelihood that the rate of contaminated items will be high enough to ruin an entire load. 

Different processing centers have different standards for evaluating the quality of the recycling load and determining how many contaminated items they sort through. 

Are plastics recyclable? 

Plastics recycling, and its effectiveness, has been a big topic in recent years. The U.S. used to export to China about 70% of plastic that consumers put out for recycling. But in 2018, China, concerned about pollution, banned most imports of plastics from other countries. This created immense strain on the U.S. recycling system, and more than 100 cities had to shut down their recycling programs altogether when the ban went into place. Now, the U.S. has started sending more plastics to Southeast Asian countries such as Malaysia and Vietnam – countries with high rates of waste mismanagement. 

On top of this are concerns that plastics recycling might not even be viable. Only 5% to 6% of U.S. plastics were recycled in 2021, down from about 9% in 2018 before China’s ban. By contrast, the recycling rates for steel, paper, and glass in 2018 were 71%, 65%, and 31%, respectively. 

Not only is the rate of plastics recycling low, but recent studies have also called out plastics manufacturers for deliberately misleading the public about the feasibility of recycling plastics. Plastic products are typically marked with a number signifying the type of plastic. But experts have said only plastics with the numbers 1 or 2 can practically be recycled – even though the other numbers are often accompanied by the recycling symbol. 

One reason that these recycling rates are so low is economic. Many recycled plastics can’t be made into commercially viable new products, so it’s not practical financially for processing centers to recycle them. It’s much cheaper for companies to just keep making new plastic. 

Another issue is that unlike a simple material such as cardboard, many plastic products are actually made up of different types of plastic polymers that would have to be separated in order to be recycled – a process that would be difficult and probably not economically feasible. 

Finally, plastics degrade faster than other recycled materials – so even when plastic is successfully recycled, that process can happen only once or twice. 

“The reality is that some types of material just don’t have any value after a single use. And so it may be recyclable in name only,” says Dr. Howell.

Does recycling still work?

Tossing an item into a recycling bin might not guarantee that it will be recycled, but the practice of recycling still has significant environmental benefits.

For example, it takes 95% less energy to recycle aluminum than it does to create an aluminum product from raw materials. In 2018, recycling saved more than 193 million metric tons of carbon dioxide equivalent, or the amount of greenhouse gases emitted by almost 42 million cars. And it creates six times the amount of jobs that landfilling does, according to the National Institutes of Health.  

Some experts are hopeful that technological innovation could improve the recycling process. Artificial intelligence machines are already in use that can sort through recycling with more speed and accuracy than humans can, preventing recyclable items from going to landfills by mistake. And a new technique called chemical recycling could help turn hard-to-recycle plastics into fuel, although there are concerns that the process produces hazardous waste.