Recycling can be confusing because of the various rules, symbols, and potential for looming tickets. Not only do towns and cities have different recycling programs, but they can also change. And anyone who always Googles “is this recyclable” is probably also wondering what those little numbers mean in the center of recycling symbols.
Resin Identification Codes
It turns out that those numbers aren’t random. Recyclable plastics are coded with the numbers one to seven. These IDs are based on the type of plastic resin used, according to the American Chemistry Council. Their official name is resin identification codes.
This information won’t change how or what you recycle—you should follow your local rules—but it is helpful for those who collect, sort, and process recycling, per greenmatters.com. Although the code is often mistaken as a universal sign of recyclability, collectors don’t accept every plastic type or number—including these 15 things you should never throw in the recycling bin.
Here’s the breakdown of each code:
Polyethylene terephthalate (PET or PETE)
The number one belongs to polyethylene terephthalate, also known as PET or PETE. PET is a popular choice for packaging because of its transparency, its strength, and its temperature stability—you can fill it with something hot. You’ll find it in the form of peanut butter jars, water bottles, and salad dressing bottles.
According to the PET Resin Association, this particular plastic is accepted at basically every recycling center across North America. This resin’s unique properties make it great for continual recycling. Annually, America recycles approximately 1.5 billion pounds of PET bottles and containers, and that number could be a lot higher. PETRA estimates that our rate of PET recycling is at only 31 percent.
High Density Polyethylene (HDPE)
The number two is code for high density polyethylene. You’ll find this code on milk jugs, detergent bottles, and some shopping bags, too. HDPE is tough, lightweight, and resistant to most solvents. It is almost as common as PET, due to its usefulness. Like PET, this resin’s properties make it great for recycling. It is widely accepted at recycling centers.
Polyvinyl Chloride (PVC, Vinyl)
Polyvinyl chloride, with the recycle symbol three, is in pipes, shampoo bottles, and spray bottles. PVC is extremely durable, and it is resistant to grease, oil, and other chemicals. And it is versatile—it can be made thin and flexible, or rigid like in industrial pipes.
Generally, PVC is recyclable. It is a contentious material, however, due to its chemical composition. These chemicals could potentially contaminate batches of plastic during the recycling process, according to the New York Times, who advise against recycling PVC. Regardless, it requires a particular recycling process. Be sure to check your local waste guidelines to learn how you should handle PVC.
Low Density Polyethylene (LDPE)
Ketchup bottles, toys, and plastic wrap use plastic type number four, LDPE. Also known as low density polyethylene, this plastic is tough, flexible, and resistant to acids, bases, and vegetable oils.
Like HDPE, number four plastics are accepted at most recycling centers. This is a more recent development, so check your local guidelines to see if it will be picked up curbside. As always, make sure you rinse well if they were used for a food item.
Medicine bottles and containers for yogurt, margarine, or syrup are made from plastic type five, PP. Polypropylene is durable and resistant to stress, even when flexed. Its high melting point makes it microwavable. The United States is well equipped to handle number five plastics, and PP is quite recyclable.
Cups, packing peanuts, and foam trays are some examples of PS plastic, or plastic with the six symbol. Polystyrene is a versatile plastic that can be made into that familiar foam material, as well as a hard, solid plastic.
Often, Polystyrene is not accepted at recycling centers. Sometimes, even if it is accepted, it won’t be recycled. Check your local guidelines for their recommendations.
The last type of plastic is a catch-all for other types. This might be on some citrus juice bottles or custom packaging. Because of its catch-all nature, plastics numbered seven are often not accepted by recycling centers.
Go forth and recycle!
Now that you know all about recycling symbols, make sure to reduce, reuse, and recycle. Plus, make sure you’re not throwing out these 11 items you didn’t know you could recycle or upcycle.
Recycling is a process that can save on money, energy, and the production of waste—and industry innovations are already bringing about change. Next, find out what recycling will look like in 10 years.