Plastics: What Do The Numbers Mean?


While we should try to avoid plastic as much as possible, it’s still important to know what’s behind those recycling symbols on plastic labels.

First things first: that three arrow symbol that appears on labels is called the Mobius Loop. It’s an internally recognized symbol that means something is capable of being recycled, not necessarily that it will be recycled; that’s dependent on local recycling systems.

When it comes to plastics, you’ll see the Mobius symbol with a number inside of it known as the Resin Identification Code. This designates the type of resin in the plastic, which also tells us…

  • whether it’s likely to be accepted by recycling systems,
  • what it’s likely to become,
  • and if it’s potentially harmful.

A few quick rules of thumb:

  • Numbers 2, 4, and 5 are regarded as the “safe” plastics.
  • In the past 4 and 5 were not widely accepted by curbside recycling, so check your local recycling programs before you give them the green light.  
  • Numbers 3, 6 and 7 could contain additives, so you want to stay away from those.
  • If possible, it’s best to also avoid 1, as bacteria has been known to accumulate in this type of plastic.

The deets:

Plastic #1 (PETE, PET): Most soda and water bottles are made of #1. With repeated use, it has the potential to accumulate bacteria. Unfortunately, one it’s contaminated, cleaning it for reuse requires harsh chemicals. Typically, PET is recycled into new bottles or spun into fiber to be used in textiles (e.g. carpet or fleece).

Plastic #2 (HDPE): Typically #2 is used in food, cleaning, and toiletry containers. It is the most commonly recycled plastic because the process to turn it into secondary uses is general simple and cheap. It’s also generally considered as the safest plastic category. 

Plastic #3 (PVC): When you see “3” think “PPP” – PVC is the Poison Plastic. Even though it stands up to weather and sunlight, it contains toxins that leach over it’s lifetime. For that reason, virgin material must be used for household applications, meaning less than 1% it is recycled. Be sure to avoid any #3 products when it comes to food or baby products. 

Plastic #4 (LDPE): Most plastic wraps, films, soft containers, and in some cases textiles, are made of #4. It’s safe, but historically it hasn’t been accepted by local recycling programs

Plastic #5 (PP): Those plastic liners in cereal boxes are made of #5. So are diapers, chip bags, bottle caps, and straws because it holds up great against moisture and grease. Like #4 it’s also safe, but, only about 3% of #5 products are currently being recycled.

Plastic #6 (PS): Also known as styrofoam, #6 is used in take-out food containers and insulation materials, such as packing peanuts. Believe it or not, #6 makes up for roughly 35% of landfill material. Worse yet, because it’s so lightweight, it’s easy for it to disperse within the natural environment if it reaches landfills (how many times have you seen styrofoam washed up on the beach?). It gets worse: especially when subjected to heat, it has the potential to leach harmful chemicals. The final kicker: it’s still not widely accepted among most recycling programs. So seriously, avoid this completely. 

Plastic #7 (Other – BPA, Polycarbonate, etc): This is the category for all non-standard plastics. BPA, a endocrine disrupter, falls into this category. While not all #7 products contain BPA, unless a a #7 product explicitly states it’s “BPA free”, you’re still running the risk. A potential point of confusion: compostable plastics are classified at #7; they should not be tossed in the recycling bin, they should be composed. The remainder of #7 plastics are not recyclable. 

When I first learned all this, it felt like it was a lot to process and remember. So, in the moments when I have to use plastic, I memorized “245” as a way to, at a minimum, remember the plastics that are considered safe. Take ten minutes to know what you can recycle and commit the nasty plastics to memory – your body and our earth thanks you.

photocred: @carsonarias

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