Plastic symbols and classifications explained 

Have you ever wondered what the symbols on the plastics we buy actually indicate? It turns out, that understanding them can have a huge impact on sustainability.

Most of the plastic in our daily lives is made from the fusion of various chemicals and oils generated by the petroleum industry. Plastics or polymers are composed of shorter compounds called monomers. Through combining these various forms on monomers into different arrangements scientists are able to create an infinite variety of plastics with all kinds of chemical properties.

A problem we face with plastic is its non-biodegradability, which affects both ecosystems and human health. As it stands, most collection and recycling systems are inefficient, poorly managed and too little is being done to resolve this impending problem. Typically only a small percentage of all plastics are recycled and what’s left is going to be with us for thousands of years. As consumers, besides trying to avoid plastic altogether, we can also be better informed on its disposal, to prevent it from ending up in the wrong places. You’ve probably spotted different numbers and letters in triangles on plastic products but never really looked into what they represent. These seven different symbols were created in 1988 with the resin identification code or RIC to get plastic off the ground and increase plastic recycling through improved separation. The seven symbols act as an index of the harmful chemical substances present, the health and safety of the plastic, it’s biodegradability and hardiness so, therefore the material's capacity for reuse.

Here is an overview.

1-  PETE or PET (Polyethylene Terephthalate) - Recyclable

Polyethylene Terephthalate PETE or PET, commonly found on single-use beverage bottles, oven-safe food trays, vegetable oven containers and mouth wash bottles. PET is so widely used because of a few key advantages; apart from being shatterproof it has a high strength to weight ratio and does not interact with the food or beverages stored within it. In addition PET and is also extremely cheap and easily recycled which is why has such a far-reaching global effect with product packaging. However, despite the sound and long term efforts only around only 20% of PET is recycled due to factors like cross-contamination. PET is often remade into new containers, carpet, furniture, bags, clothing fibres and even polar fleeces. The chemicals used are considered as safe if the appropriate measures have been enforced to deal with it.

2 - HDPE or PE-HD (High-Density Polyethylene) -  Recyclable

High-density polyethylene (HDPE) can be found holding your milk, shampoo, motor oil and household detergent. This is another lightweight and super durable plastic that is impact resistant, which is why you often find it carrying thicker liquids. Much like PET, HDPE bottles are one of the most widely recycled items.

3 - V or PVC (Polyvinyl Chloride) - Rarely Recyclable

Recycling contractors rarely accept vinyl or PVC. The chemicals in PVC are seen as being far too hazardous to be reused. It contains phthalate and DEHA which are contributing factors to liver problems and bone density diseases. When and if PVC is recycled it is often used structurally for cables, speed bumps, flooring, gutters, panelling and decks.

4 - LDPE or PE-LD (Low-Density Polyethylene) - Rarely Recyclable

LDPE has a lower density of HDPE, meaning it has a smaller mass to volume ratio. This plastic is found in ordinary shopping bags, squeezable bottles, dry cleaning, frozen food or bread bags and is considered a relatively safe plastic when it comes to toxicity. However, because of its thinness, it is more susceptible to breakage or leakage, which is why it is not often recycled. However, it is likely to be collected if it is rigid yet flexible, like, lids, containers and bottles while, LDPE bags and wraps are not. To be sure of this individuals need to check their local waste contractor and collection guidelines.

5 - PP (Polypropylene) - Recyclable

You can find PP in Medicine bottles, straws, bottle caps, ketchup bottles and syrup bottles as well as some yoghurt containers. PP is popular because it is a thermoplastic, which means it responds well to heat and insulation. For example, PP has a melting point of 130 degrees Celsius which is why it is often used to carry hot liquids. You will find that the texture of this plastic if often strong and elastic and that it’s primary useful attribute is that it can be heated to its melting point, cooled and then reheated into new forms like trays, bins, rakes, brushes, brooms and battery cables. PP is recyclable but individuals will need to check if they are accepted by curbside recycling or if they need to be disposed of at the recycling centre.

6 - PS (Polystyrene) Rarely Recyclable

PS is found holding single-use cups and plates, compact disc cases, aspirin bottles, take-out containers, some egg cartons, and meat trays. Styrofoam or polystyrene, is difficult to recycle, because of its springy texture and lower density, it is for this reason that there have been many bans on all polystyrene together, due to its lasting and harmful impact on the environment.  

7 - Misc. plastics (BPA, Polycarbonate and Lexan) Non-recyclable

Plastic that doesn’t fall under any of the above often carries a number 7 in the triangle. Collection recycling systems do not accept these kinds of plastics as they often contain Bisphenol-A (BPA) which is a regularly occurring toxic chemical which is a threat to human health. It is important to know that some plastics that sit under this category carry the symbol. Therefore, individuals must be vigilant of products like CD’s, nylons, glasses, computer cases, signs, displays and cassettes.

Text by Michelle Torres