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Here's What the Numbers on Your Plastic Bags Mean

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1, 2, ... 7. If you pay attention to any plastic packaging out there, you’ll find a number printed on its side. These numbers are called the Resin Identification Code, and they pose a very important role in waste management or specifically recycle system.

Hans [4]

Plastics, when improperly managed, are harmful to our health and environment. However, some plastics are more damaging than others, raising the question of whether its existence is necessary, to begin with. Because there are different types of plastics, the Resin Identification Code tells us what plastic has been used for that packaging, and if it’s recyclable [1].

Plastics are still extremely popular due to production efficiency and cost, so If you can't stop using plastic completely, let's at least be aware of each code’s differences.

SPI, The Society of Plastic Industry, classified those numbers as a guide for different purposes and waste management systems [2]. Here’s how the list goes:

① PET (Polyethylene Terephthalate)

It’s almost impossible to have never encountered PET plastic at least once in your life. PET is widely used in consumer goods, disposable packaging, and coatings. Although they are highly recyclable, due to it being cost-effective and durable, they are also among the highest plastic pollutants on the planet.

Bin Foch [5]

Appearance: Transparent, bendable, and thin

Used for: Common disposable beverage and food products e.g. bottled water

Safety: Could leak Carcinogens (a substance known to cause cancer) into the liquid inside it

Reusable: Not recommended, there will be discoloration and chemical leaching after some time

Recyclable Level: Easy (Highly recyclable, when sent to a proper recycling system)

② HDPE (High-Density Polyethylene)

Another plastic that we use on a daily basis is HDPE. Its thickness is very reliable to store liquid-based ingredients such as hygiene products. Although this plastic is easy to recycle, its mass production raises plastic pollution. Hence, reusing the container for a refill is recommended.

Polina Tankilevitch [6]

Appearance: Non-transparent with medium thickness

Used for: Dense beverages and other liquid hygiene products e.g. shampoo, juice bottle

Safety: Safe and rarely leach

Reusable: Not for edible products, but safe for refills e.g soap/shampoo bottles

Recyclable level: Easy (Highly recyclable, when sent to a proper recycling system)

③ V (Polyvinyl Chloride/PVC)

Due to its durability, PVC is mostly used for house plumbings and pipes. However, this type of plastic is rarely recycled and contains toxic additives which can leach out over time. The best way to deal with used/scrap PVC is by recycling.

Kyle Glenn [7]

Appearance: Thick and firm plastics, but will crack if stressed

Used for: Buildings knick-knacks e.g. plumbing pipes

Safety: Contains dangerous chemicals, not to be ingested, and cannot be used under high temperatures

Reusable: Not recommended

Recyclable level: Difficult (Limited recycling and rarely recycled, must be sent to specific PVC recycling companies)

④ LDPE (Low-Density Polyethylene)

LDPE is a low-density version of HDPE. If HDPE is firm and thick, LDPE is the opposite. The similarity is that both are resistant to water, making it practical to store any liquid. Nevertheless, it is only recommended to be used for dry items as it is low-density and may cause leaks or even leach its own chemical matters.

Ruth Alarcon [8]

Appearance: Transparent, very thin, durable, and flexible

Used for: Grocery bags, Cling-film for instant foods

Safety: Safe to use, but not to store foods and beverages in high temperatures

Reusable: Very recommended, when you need to store any dry items from the market

Recyclable level: Difficult (Rarely recycled, must be sent to specific LDPE recycling companies)

⑤ PP (Polypropylene)

This plastic is the adequate solution to store foods and also endures the food-heating process as it is heat-resistant and is unlikely to leach chemicals. It is also one of the BPA free plastics, which is a chemical compound that is bad for our health [3]. Although BPA is more commonly found in plastics number 3 and 7, make sure to check the BPA-free signs before buying food and water containers as a precaution.

Caroline Attwood [9]

Appearance: Very thick and firm

Used for: Microwave-safe kitchenware e.g. lunch boxes

Safety: Safe, heat-resistant, and mostly BPA free

Reusable: Yes, as long as the color and shape are still intact

Recyclable level: Moderate (Recyclable but only occasionally, only recently gaining recognition)

⑥ PS (Polystyrene/Styrofoam)

Plastic number 6 thrives in the restaurant and event industries as its cost and time effectiveness are the desirable for take-aways. Unlike the previous food and beverage containers, PS is more likely to leach its chemical such as carcinogen or styrene that promotes the formation of cancer. This may be a great solution for instant consumption, but not for our bodies and or our planet.

Bluebudgie [10]

Appearance: Usually colored in white, flexible, soft, and can be torn

Used for: Disposable kitchenware e.g. cutleries, coffee cups, food containers

Safety: Harmful, High chance of leaching its chemicals

Reusable: Not recommended

Recyclable level: Very difficult (Mostly rejected by recycling companies)

⑦ Other / Mixed

Just like its name, no. 7 is for any kind of plastic that falls outside the numbers above and even in between. Most of it is the product of combining two or more types of plastics, making it hard to be defined and managed in terms of recycling. It is also known to be hazardous for our health, therefore avoid all food/drink containers that are classified as no. 7!

Brett Jordan [11]

Appearance: Various, because this kind of plastic isn’t consisted of particular chemicals, mostly mixed or combined. Mostly very firm but can shatter if stressed.

Used for: Compact disc, reading glasses, reusable bottles, oven baking bags

Safety: Harmful, most contains highly toxic chemicals e.g. BPA

Reusable: Not to store edible products

Recyclable level: Difficult (The combined materials makes it harder to pinpoint the recycling requirements)

To sum up, plastics classified as no. 1, 2, 4 and 5 are considered plastics that are low to moderately hazardous, while no. 3, 6, and 7 are highly hazardous. Avoid 3 and 7 because they are the types that contain BPA the most. Don't forget the BPA-free logo and keep these numbers in mind!

Nevertheless, the best option is to go plastic-free! By choosing environmentally friendly materials, using reusable and recycled goods, you have less health concerns, environmental implications, and no chemical toxins to be worried about!


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