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What do the recycling numbers mean?

At the bottom of most plastic containers you can find a small number inside the three arrow triangle recycling symbol. This number is a reference to what type of plastic the container is made of. Each plastic is composed of a different molecule or set of molecules. Different molecules do not mix when plastics are recycled, it is like trying to recycle paper and glass together. For this reason they need to be separated. The recycling numbers are a uniform way of classifying the different types of plastic and it aids recyclers in the sorting process. Note that sometimes other numbers are found on the bottom of plastic containers, but only numbers inside the recycling symbol are valid for recycling purpose.

The recycling code constitutes of the numbers 1 through 7. Sometimes below the numbers you also find the abbreviations for the plastic type (PETE, HDPE, etc.). The most widely accepted plastics for recycling are number 1 and 2, also most of plastic containers are type 1 and 2. Below is a list of the numbers, full names of the plastics they refer to, and some examples of common containers made of that product.

Number 1 - PETE - Poly(ethylene terephthalate):
Soda bottles, water bottles, cooking oil bottles, and medicine containers.

Number 2 - HDPE - High-density Polyethylene:
Containers for: laundry/dish detergent, milk, shampoo, conditioner, also various toys, and grocery bags.

Number 3 - V - Poly(vinyl chloride):
Pipes, shower curtains, clear medical tubing, vinyl dashboards and seat covers.

Number 4 - LDPE - Low-density Polyethylene:
Wrapping films, grocery bags, and sandwich bags.

Note that most cities accept plastics #4 for recycling, but NOT grocery bags (these can stuck in the sorting machines).

Number 5 - PP - Polypropylene:
Tupperware, yogurt tubs, (orange) medicine containers, and plastic caps of soda bottles.

Number 6 - PS - Polystyrene:
Plastic cups, disposable cutlery and cups (clear and colored), coffee cups, packing peanuts, Styrofoam insulation.
Note that most cities accept plastics #6 for recycling, but NOT styrofoam, peanuts, etc. (these are contaminated by food easily).

Number 7 - OTHER:
They are made of any combination of 1-6 or another, less commonly used plastic.

Biodegradable plastics, like cups made of corn, are NOT recyclable. Though they have the recycling #7, this only means "other plastics", including non-petroleum based.

Note that soda bottles and caps should be separated before recycling, as usually bottles are number 1 and caps are number 5, and different types of plastic do not recycle together.

The products shown are just examples, so when sorting recyclables always check the recycling number imprinted on the bottom of the plastic item.


The recycling symbol code was designed by The Society of the Plastics Industry (SPI) in 1988. Since recyclers target post-consumer plastics, the recycling symbols are most commonly found on household packaging materials.

The SPI and the Federal Trade Commission (FTC) guidelines for use of the recycling code are the following:
  • Used on bottles and rigid containers in compliance with laws in 39 states (US).
  • Identifies resin (type of plastic) content only.
  • Must be as inconspicuous as possible so the consumer's purchasing decision is not influenced.
  • Must not be modified in any way.
  • No claims of recyclability or the word 'recyclable' near the code symbol.
  • Molded or imprinted on all 8 ounce to 5 gallon containers that can accept the 1/2" minimum size symbol.
  • Must appear on the container bottom as close to the center as possible.
For more information on the guidelines see the SPI web page.

References:


- What do those recycling numbers mean? pslc.ws/mactest/work/recycle.htm

- Deciphering the numbers on plastic bottles: www.valcorerecycling.org/affair/archives/2002-08-04.htm

- SPI plastic industry: www.plasticsindustry.org


- Know your plastic recycling number: dustbowl.wordpress.com/2008/06/14/know-your-plastic-recycling-number
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