Recycling — The Difference Between the Numbers

 Recycling has been around forever it seems and it is the one planet friendly activity that most all of us complete on a regular basis. With scheduled pickups in most areas, or large drop off locations in others, even people who don’t consider themselves Green have the chance to make a positive environmental impact on the Earth by keeping petroleum based products out of landfills.

Paper, corrugated cardboard, glass and metal have become standard items to recycle in most areas but the plastics that have made their way into our homes or businesses are all stamped with that little triangle and it can become slightly confusing as to just what the numbers inside that triangle mean. Hopefully this cheat sheet guide to some of the most popular plastics numbers will help everyone determine just what is, and what isn’t, accepted by most larger recycling stations.

The numbers system was introduced in 1988 (hard to believe but it was twenty two years ago!) so consumers would be better able to sort through the plastic products they had and determine just which were acceptable to recycle in their area. The numbers signify the type of resin used, and the grade of plastic, and most towns, counties, states, countries, etc. have a list posted as to which they take.

Here in the city of Boston everything but number 6 is accepted in our big recycling cans. And we put in even the teeniest bit of plastic if it is accepted because after all, the more recycled the better!

So what does each number stand for? Well I’m glad you asked!

Number 1 – Known in most circles as PET, Polyethylene Terephthalate, is the most widely accepted plastic type. It is the plastic that is used to create soda or water bottles and when broken down it is most commonly turned into more bottles.

Number 2 – This one is also commonly recycled in most areas. HDPE (high density polyethylene) is what that bottle of fabric softener or hydrogen peroxide is made from. Again, it is primarily turned back into bottles when broken down.

Number 3 – Here’s where things start to get tricky. Do your children have toys made from hard plastic? Was your plumbing replaced in the last five years? If so then you probably have some polyvinyl chloride (or PVC) in your home. This type is very tough to recycle and potentially hazardous to the health of all living things*. Because it doesn’t ever completely break down, it is the number one type of plastic floating around in the Pacific Garbage Patch.

Number 4 – Unlike its tougher cousin, 2, LDPE (low density polyethylene) is used to create things like grocery store bags. It may not always be stamped with a symbol so check with your local recycling centers to see if, and how, this can be recycled.

Number 5 – Simply referred to as PP (polypropylene), this is the type of plastic used to create fibers that need durability to withstand tough conditions. Think sailing rope, a shower surround or outdoor furniture. Again, this is tough to recycle so ask around!

Number 6 – Ah yes, the dreaded number 6. PS, or polystyrene, in its most basic nickname as dubbed by Dow, is what we all know as Styrofoam. It is used to protect items during shipping because it can be heat molded to just about any shape. Coffee cups, electronic’s packaging, peanuts, the teeny little balls in a bean bag chair — all made from PS. The stuff is a bear to recycle and with its lightweight properties it has the propensity to float aimlessly anywhere (try chasing those peanuts if your ceiling fan is going!). It is highly flammable, made from petroleum, and known to be hazardous to humans yet it is still found everywhere (hello, under that chicken you just bought). The bad news is that most places do not take this type at all and therefore it is consistently sent to landfills. It will break down eventually but the process for this type takes centuries (and that is if it doesn’t float off into the waterways first, and we all know what happens then). So what can we do? Well this website has some fantastic tips for how to reuse it if it makes its way into your home or office but the best solution of course is to try to avoid the stuff whenever possible!


The mantra – reduce, reuse, recycle – is great but refuse could also be added to the mix, especially when discussing plastics. At this time of year especially, with gift giving and shipping of presents all over the globe, it is important to keep in mind the impact that plastics not only have on the planet but all the living things on it. By lessening our consumption or recycling all that we can we will have a positive impact. And that’s the best holiday gift of all!

*Click for more information on PVC and its environmental impact.

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  1. Thank you for this clear and concise article, I’ll provide a link back on our Upcycling resource page for our team. Your team rocks!

  2. Thanks for this article. even though the number system does not exist in Australia – and I can tell you Australia is a shocker when it comes to recycling. But the article has got a few interesting news for me – so thanks for that.
    and yes REFUSE is the story really.

  3. Great article! I recycle everything or re-use what I can always. I really like the idea of adding REFUSE to the recycling circle, I am trying to do that more and more, using metal water bottles, glass food containers with lids instead of plastic reusable ones or plastic wrap etc.

    I know my dad was taking all of his #6 meat trays and stacking them together, then putting them in his attic to use as insulation, lol. I think that is a very creative use for them.

    I do want to share a link to a place that recycled #6 plastics. I happen to have a drop off site very close to me in Tumwater WA, which is great! They have 13 different drop off sites across the US and 1 in Canada and mexico. You can find the drop off sites list here:

    They take all #6 except for packing peanuts. I do know that almost all mailboxes etc and places like that will take packing peanuts to be re-used though, so don’t throw them away. Also, I bet there are other companies like Dart that take #6 to be recycled, so do your research if there is not a Dart one in your area.

  4. Thank you for this article. Recycling #’s can be so confusing and breaking them down this way is really easy to discern what to do with all the plastics we come across. Of course, the thing to do is to do is, like you said, “REfUSE”.

    #7 that was not mentioned here is Polycarbonate – think, Nalgene water bottles, big blue drinking water tank bottles, baby bottles and most likely with BPA – but also, everything else that’s not labeled as #1-#6. And multi-layered plastics. And yes, they are not recyclable.

    Also, you have to check with your sanitation department in your town to see which numbers can be recycled. Some towns, like mine, can only take #1 and #2 and the rest are garbage. (Although by 2012, my town is planning to take ALL plastics)
    So, just because plastics have the recycling symbol (Mobius) on them do NOT mean that they are recyclable.

    Another complicated issue that I’ve been grappling with is the end product from recycled plastics that no longer become recyclable. Recycled playground equipments, eco-felts, clothes and accessories made from recycled plastics are no longer recyclable after usage. All these industries that are popping up everywhere, using recycled plastics are making us to believe that as long as plastics are recyclable, it’s OK for us to consume. As Ed Begly Jr. at TEDxGreatPacificGarbagePatch (if you haven’t watched any talks from it, go to their website and listen to some awesome speakers, including some phenomenal kids!) conference stated, Recycling is like a pig with lipstick. It’s still plastic we are talking about. I think the most responsible thing to do is to REFUSE plastics in the first place, like Jenn stated here.

    Off from the soap box. :)