The Puzzle of Plastics Recycling, By the Numbers

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Most people have bought carry out or eaten fast food in the past month, or bought something online – meaning you’ve dealt with the pesky plastic packaging that comes along with it. After buying these items, have you ever wondered is this type of packaging recyclable?

It’s a legitimate question and many people ask it every day. The answer, unfortunately, is not a simple yes or no.



Back in 1988, the recycling symbol code was created and designed by The Society of the Plastics Industry (SPI) to help provide a standard and uniform method to identify different types of plastics. This code ensures that the numbers inside the recycling symbol on plastic containers are the only numbers valid for the purpose of recycling.

There are seven different recycling codes for plastic products. Recycling codes distinguish products made with different types of plastic and are processed and recycled separately because of this. While it used to be that consumers separated their own plastics for recycling, the move toward “single stream” recycling in recent decades has pushed the sorting process to facilities called Material Recovery Facilities, or MRFs. Nowadays, robots and artificial intelligence even help with the sorting.

IHS Metal Recycling specializes in recycling metal, and we don’t accept plastic goods at our recycling centers; other waste management companies are better set up to handle that material than we are. However, IHS Metal Recycling does handle some post-industrial plastics – think, scrap byproduct from the manufacturing process, or plastic products that failed quality control, in bulk. Our resident plastic specialist is Shawn Elam.

Plastic is less straightforward than other materials, especially the Number 7 category,” Shawn explains (more on that below). “Plastics have to be segregated, especially in the post-industrial world. Not everything has a production mark saying what it is.” The only way to tell for sure what a plastic is made of, he says, is to do a burn test – a skill that takes years to master. And definitely, definitely should not be attempted at home.

Let’s walk through the seven types of plastic and how they are – or aren’t – recycled.


Number 1: PETE or PET

Polyethylene terephthalate

  • 1 plastic is normally clear in color and most commonly found in items like soda bottles, water bottles, peanut butter jars, salad dressing bottles, medicine containers and vinegar bottles.
  • No. 1 plastics are recyclable and can be picked up by most curbside recycling programs.
  • When No. 1 plastic is recycled, the plastic can be crushed and shredded into small pieces to make new plastic containers and bottles, or it can be recycled into polyester fiber to help make carpets and stuffing.
Number 2: HDPE

High-density polyethylene

  • Products made of No. 2 plastic are usually opaque and cloudy in color.
  • Common products made of HDPE plastic are milk jugs, laundry detergent bottles, shampoo/conditioner bottles, and bleach bottles.
  • Products made with HDPE plastic are reusable and recyclable; this type of plastic is also accepted by most curbside recycling programs.
  • The No. 2 plastics are usually heavier containers than No. 1 plastics and can be recycled into toys, picnic tables or even waste bins.
Number 3: PVC 

Polyvinyl chloride

  • No. 3 plastics include pipes, shower curtains, clear medical tubing, vinyl records, cooking oil bottles, seat covers, and coffee containers.
  • Products made with No. 3 (PVC) plastic are very difficult to recycle, which has to do with how this plastic melts.
  • No. 3 plastics are not accepted by most curbside recycling programs.
Number 4: LDPE 

Low-density polyethylene 

  • LDPE can be thought of as plastic film: sandwich bags, shrink wrap, grocery bags, squeezable condiment bottles and bread bags.
  • Products made with No. 4 plastic are reusable, but not all products of them are recyclable.
  • Most curbside recycling programs will not accept No. 4 plastic products. The product is so lightweight that it takes a massive volume to make it worth selling, and is not easy to store.
Number 5: PP


  • No. 5 plastics make items like yogurt cups, ketchup bottles, syrup bottles, plastic bottle caps and ‘microwave-safe’ plastic containers.
  • No. 5 plastics are accepted by some curbside recycling programs, but make sure to check with your local  program before you toss it in, as this is far from universal.
  • When No. 5 plastics are recycled, they can be used to make products like battery cases and trays.
Number 6: PS

Polystyrene or Styrofoam (brand name)

  • Products that contain No. 6 plastic are items like disposable cups, take-out food containers, packing peanuts, egg cartons and Styrofoam insulation.
  • No. 6 plastic technically can be reused and recycled, but the process is difficult and costly, and not widely used. Most curbside recycling programs will not accept polystyrene.
  • No. 6 plastic should not be burned. Doing so releases harmful ozone-depleting gases.
Number 7: Other

  • No. 7 products can be produced from any combination of No. 1 – 6 plastics or from a less commonly used plastic.
  • When plastic food packaging is made from polycarbonate (this includes the toxic BPA), they are often marked on the bottom with the letter’s ‘PC’ next to the No. 7. It is a good habit to check your plastic containers for these markings, as there are some known health risks with storing food and beverages in BPA.
  • Another type of plastic in the No. 7 category is biodegradable plastic; this plastic can be used as an alternative to polycarbonate plastics. It is created from plant-based polymers, like corn, which allow it to break down and decompose – though this is generally only possible in a professional composting facility, not in landfills.
  • It is very difficult to recycle the No. 7 plastics since most products in this category can be made from any combination of the different plastics. Because of this, most curbside recycling programs will not accept No. 7 products.

Learning and understanding these seven plastic recycling codes makes it easier to know which products are safe to recycle and which ones are not. The items listed above are just examples of different plastic products, so make sure to check the bottom of your plastic products and with your local recycling program to ensure you are recycling correctly. Different cities have different rules and guidelines, so it is always good to double check before recycling something that should not be.

The science of plastics is changing every year, and new developments have created opportunities for more sustainable plastic use, as well as challenges. The invention of a new plastic, or a new process, can have implications for the recycling stream of another. As users of plastic, the best thing each of us can do is be attentive to recycling properly, and recycling as often as possible.