What’s Up with Those Numbers?

Since its invention in the 1800’s, plastics have changed our world for the better.  Where would we be without plastic for our plumbing, televisions, cell phones and computers?

Photo used under Creative Commons from vonslatt

Of course, most people know that the overuse and disposal of plastic is negatively impacting our planet.  Plastics can take hundreds, possibly thousands, of years to biodegrade.  Every water bottle, every cell phone, every plastic bag you ever threw in the trash is still sitting in a landfill somewhere, just…sitting.  Or maybe it’s in the Great Pacific Garbage Patch; estimates of this giant mass of garbage floating in the Pacific ocean have it larger than the state of Texas!  Most of that trash originated on land and consists of mostly plastic and chemical sludge that has been drawn together by the ocean currents.  It’s very harmful to marine life; animals sometimes eat the plastic, mistaking it for food, or get caught up in the plastic.   In addition, the islands that are in these ocean currents get massive quantities of trash washing up on their shores.

Photo used under Creative Commons from How can I  recycle this

That’s where the three Rs come into play: Reduce-Reuse-Recycle.  We’ve already talked about the three Rs on this blog, but today I’d like to delve more deeply into recycling.

The most common complaint people have when it comes to recycling plastics is that it can be somewhat confusing.  Because different types of plastic require different processing to be reformulated and re-used as raw material, municipalities have varying rules and restrictions regarding what kind of plastic you can and cannot recycle.

To distinguish between different types of plastic, The Society of the Plastic Industry designed resin codes that could be molded or imprinted on plastic items.  The code numbers range from 1 thru 7 to identify the group of plastics the item was made from.  The Daily Green has the following descriptions:


Number 1 Plastics
PET or PETE (polyethylene terephthalate)
Found in: Soft drink, water and beer bottles; mouthwash bottles; peanut butter containers; salad dressing and vegetable oil containers; ovenable food trays.
Recycling: Picked up through most curbside recycling programs.
Recycled into: Polar fleece, fiber, tote bags, furniture, carpet, paneling, straps, (occasionally) new containers

PET plastic is the most common for single-use bottled beverages, because it is inexpensive, lightweight and easy to recycle. It poses low risk of leaching breakdown products. Recycling rates remain relatively low (around 20%), though the material is in high demand by remanufacturers.

Number 2 Plastics
HDPE (high density polyethylene)
Found in: Milk jugs, juice bottles; bleach, detergent and household cleaner bottles; shampoo bottles; some trash and shopping bags; motor oil bottles; butter and yogurt tubs; cereal box liners
Recycling: Picked up through most curbside recycling programs, although some allow only those containers with necks.
Recycled into: Laundry detergent bottles, oil bottles, pens, recycling containers, floor tile, drainage pipe, lumber, benches, doghouses, picnic tables, fencing

HDPE is a versatile plastic with many uses, especially for packaging. It carries low risk of leaching and is readily recyclable into many goods.

Number 3 Plastics
V (Vinyl) or PVC
Found in: Window cleaner and detergent bottles, shampoo bottles, cooking oil bottles, clear food packaging, wire jacketing, medical equipment, siding, windows, piping
Recycling: Rarely recycled; accepted by some plastic lumber makers.
Recycled into: Decks, paneling, mudflaps, roadway gutters, flooring, cables, speed bumps, mats

PVC is tough and weathers well, so it is commonly used for piping, siding and similar applications. PVC contains chlorine, so its manufacture can release highly dangerous dioxins. If you must cook with PVC, don’t let the plastic touch food. Also never burn PVC, because it releases toxins.

Number 4 Plastics
LDPE (low density polyethylene)

Found in: Squeezable bottles; bread, frozen food, dry cleaning and shopping bags; tote bags; clothing; furniture; carpet
Recycling: LDPE is not often recycled through curbside programs, but some communities will accept it. Plastic shopping bags can be returned to many stores for recycling.
Recycled into: Trash can liners and cans, compost bins, shipping envelopes, paneling, lumber, landscaping ties, floor tile

LDPE is a flexible plastic with many applications. Historically it has not been accepted through most American curbside recycling programs, but more and more communities are starting to accept it.

Number 5 Plastics
PP (polypropylene)
Found in: Some yogurt containers, syrup bottles, ketchup bottles, caps, straws, medicine bottles
Recycling: Number 5 plastics can be recycled through some curbside programs.
Recycled into: Signal lights, battery cables, brooms, brushes, auto battery cases, ice scrapers, landscape borders, bicycle racks, rakes, bins, pallets, trays

Polypropylene has a high melting point, and so is often chosen for containers that must accept hot liquid. It is gradually becoming more accepted by recyclers.

Number 6 Plastics
PS (polystyrene)
Found in: Disposable plates and cups, meat trays, egg cartons, carry-out containers, aspirin bottles, compact disc cases
Recycling: Number 6 plastics can be recycled through some curbside programs.
Recycled into: Insulation, light switch plates, egg cartons, vents, rulers, foam packing, carry-out containers

Polystyrene can be made into rigid or foam products — in the latter case it is popularly known as the trademark Styrofoam. Evidence suggests polystyrene can leach potential toxins into foods. The material was long on environmentalists’ hit lists for dispersing widely across the landscape, and for being notoriously difficult to recycle. Most places still don’t accept it, though it is gradually gaining traction.

Number 7 Plastics
Found in: Three- and five-gallon water bottles, ‘bullet-proof’ materials, sunglasses, DVDs, iPod and computer cases, signs and displays, certain food containers, nylon
Recycling: Number 7 plastics have traditionally not been recycled, though some curbside programs now take them.
Recycled into: Plastic lumber, custom-made products

A wide variety of plastic resins that don’t fit into the previous categories are lumped into number 7. A few are even made from plants (polyactide) and are compostable. Polycarbonate is number 7, and is the hard plastic that has parents worried these days, after studies have shown it can leach potential hormone disruptors.

So now that you know what’s what, you can make sense of your town’s rules regarding recycling.  Some towns even offer single stream recycling, which means that all you have to do is put all your recyclables (paper, glass, plastics and metals) into one bin (just make sure they’re clean)  and put the bin by the curb once a week.  There are a few restrictions there, too, but it is much easier for the consumer and should result in more items being recycled.

Plastics have only been around for about 150 years and yet we have landfills full of plastic and our oceans are being poisoned by it.  According to the Clean Air Council, “In the U.S., 4.39 pounds of trash per day and up to 56 tons of trash per year are created by the average person.”   So get that blue bin and do your part by recycling!

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