Published: Oct. 26, 2020

Recycling Symbol on Plastics = Resin Identification Code

We’ve all seen the recycling symbol on the bottom of plastic items that usually includes a number inside the chasing arrows... but what does this symbol really mean?

  • A common misconception is that the recycling symbol on a plastic item indicates it is recyclable
  • This symbol is actually called a plastic resin identification code
  • It refers to what specific type of plastic the item is made from
  • You must check your local recycling guidelines to see acceptable materials in your area
    • On campus at CU, we follow the Boulder County guidelines, but have a slightly different collection system inside academic/admin buildings for dual stream materials
  • If you see a #1, #2, or #5 inside the recycle symbol, these types of plastic are most commonly recyclable in curbside programs across the country
  • If you see a #3, #4, or #6 inside the recycle symbol, these types of plastics can often be accepted in some type of special collection program for “hard to recycle materials”
    • These “hard to recycle materials” cannot go into your normal recycling bins (curbside or in buildings)
      • On campus at CU, we have several options for hard to recycle materials
        • If there is not a special collection program for these items, they must go to the landfill (sadly)
  • If you see a #7, this is a tricky one… it signifies ALL other plastic types
  • #7 plastics are most commonly NOT recyclable and must go to the landfill
  • #7PLA = Compostable
    • Compostable PLA plastics are also included in the #7 category 
      • This is very confusing!
        • #7PLA is type of plant based starch used to make plastic and will compost in and industrial composting facility (not in your backyard compost)
        • #7PLA plastics will contaminate the recycling process since they have a different chemical composition and melting temperature than other plastics
        • Remember… the recycle symbol on plastics does not mean they are recyclable
        • #7PLA plastics are not recyclable, even though they are labeled with a recycling symbol and look like other plastics

Look at the graph below to understand the plastic resin identification codes in more detail.

  • The colors on the graph mean: 

  • green: types of which are easiest to recycle and thus accepted at most curbside recycling programs (aka you can throw it in your recycling bin!) 

  • yellow: types of plastic which you usually have to take to a special program to recycle (ex. #4 plastic grocery bags which you can take to a Target or other participating store to recycle through their programs 

  • red: can’t be recycled! This is just #7. Items that say #7 PLA are compostable (but NOT recyclable!) as they are polyactic acid “plastic” which is actually made from corn instead of fossil fuels!