Greengreen livingimageplasticrecycle

Plastic Identification Codes & Plastic Recycling

You’ve probably noticed on most plastic products a recycling symbol with 1, 2, 3, 4, 5, 6 or 7 along with letters. So what are these exactly? The SPI resin identification coding system is a set of symbols placed on plastics to identify the polymer type. The symbols used in the code consist of arrows that cycle clockwise to form a rounded triangle and enclosing a number, often with an acronym representing the plastic below the triangle. When the number is omitted, the symbol is known as the universal Recycling Symbol, indicating generic recyclable materials.  It was developed by the Society of the Plastics Industry (SPI) in 1988, and used internationally.  Let’s take a look at the 7 plastic identification codes.


Plastic Identification Code Type of plastic polymer Properties Common Packaging Applications
Polyethylene Terephthalate (PET, PETE) Clarity, strength, toughness, barrier to gas and moisture. Soft drink, water and salad dressing bottles; peanut butter and jam jars
High Density Polyethylene (HDPE) Stiffness, strength, toughness, resistance to moisture, permeability to gas. Milk, juice and water bottles; trash and retail bags.
Polyvinyl Chloride (PVC) Versatility, clarity, ease of blending, strength, toughness. Juice bottles; cling films; PVC piping
Low Density Polyethylene (LDPE) Ease of processing, strength, toughness, flexibility, ease of sealing, barrier to moisture. Frozen food bags; squeezable bottles, e.g. honey, mustard; cling films; flexible container lids.
Polypropylene (PP) Strength, toughness, resistance to heat, chemicals, grease and oil, versatile, barrier to moisture. Reusable microwaveable ware; kitchenware; yogurt containers; margarine tubs; microwaveable disposable take-away containers; disposable cups and plates.
Polystyrene (PS) Versatility, clarity, easily formed Egg cartons; packing peanuts; disposable cups, plates, trays and cutlery; disposable take-away containers;
Other (often polycarbonate or  ABS) Dependent on polymers or combination of polymers Beverage bottles; baby milk bottles; electronic casing.

Source: Wikipedia: Plastic recycling

Most plastics can be recycled, but they have to be separated into their different polymer types. Contrary to misconceptions, the number does not indicate how hard the item is to recycle, nor how  often the plastic was recycled. It is an arbitrary number and has no other meaning aside from identifying the specific plastic.

Use of the recycling symbol in the coding of plastics has led to ongoing consumer confusion about which plastics are readily recyclable. In most communities throughout the United States, PETE and HDPE  are the only plastics collected in municipal recycling programs. Some regions, though, are expanding the  range of plastics collected as markets become available (Los Angeles, for example, recycles all clean  plastics numbered 1 through 7).

When recycling plastic:

  • Rinse and sort your plastic containers by number. Recyclable plastic often must be separated by number in order to avoid contamination as it begins the recycling process
  • Recycle type 1 (PETE) and type 2 (HDPE) plastic containers at your curb
  • Drop off plastic grocery bags – usually type 4 (LDPE), sometimes type 2, though not always marked – at your grocery store to be recycled
  • Most recycling programs do not recycle types 3, 5 and 7.  While some of these are recyclable, the plastics industry is still in the early stages of recycling and does not recycle these in most cities  unless it is through a test program.
  • For type 6, call the Alliance of Foam Packaging Recyclers, (410) 451-8340, or look at the expanded polystyrene (EPS) packaging drop off locations to find the nearest type 6 drop off center  to you.
  • Take caps and pump spray tops off of plastic containers unless they are marked with a number. They  are often made from a type of plastic that is different from the main part of the container and  generally are not recyclable

Hopefully in the near future more cities will be able to recycle all types of plastic.  The quantity  of post-consumer plastics recycled has increased every year since at least 1990. In 2006 the amount of  plastic bottles recycled reached a record high of 2,220,000,000 pounds. The amount of PET bottles  recycled in 2006 increased more than 102 million pounds compared to 2005. HDPE bottle recycling  increased in 2005 to 928 million pounds. All plastic bottles were recycled at a rate of 24 percent in  2005.  Click here for plastic decomposition rates.   In order to get plastic out of landfills and elsewhere we need to recycle more plastic.  Also, use more  eco-friendly products rather than using plastic.

Clay Miller
the authorClay Miller
I am the creator/writer of and I'm an advocate for oceans, beaches, state parks. I enjoy all things outdoors (e.g. running, golf, gardening, hiking, etc.) I am a graduate of the University of Kentucky (Go Wildcats!!). I'm also a huge fan of the Pittsburgh Steelers. I was born and raised in the beautiful state of Kentucky.

This site uses Akismet to reduce spam. Learn how your comment data is processed.