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How To Identify Plastic Types Around You

July 9, 2022

How To Identify Plastic Types Around You

We’re so used to water bottles and gallons of milk that we don’t question it, but there are many different types of plastic. Some are reusable materials, while others are considered hazardous and require immediate disposal.

If you want to know the basics of plastics and what each type represents, you’ve come to the right place.

In this article, we’ll take you through how to identify plastic types based on their appearance and feel.

In this guide, we’ll cover the following on plastic identification:

  • What Are the Different Types of Plastic?
  • How To Identify Different Plastic Types  
  • How Different Types of Plastic Affect the Environment

What are the different types of plastic?

There are mainly seven different types of plastic. The classification of each one depends on chemical structure and compliance with laws and restrictions.

Polyethylene Terephthalate (PET or PETE)

A recyclable wrinkle-free fiber that prevents oxygen from spoiling the contained product. Mainly used for packaging foods and liquids like water bottles and soda.

High-Density Polyethylene (HDPE)

This type of plastic is much thicker and more durable than PET, thanks to its unbranched polymer chains. Products that use HDPE can exist in containers of juice or shampoo.

Polyvinyl Chloride (PVC)

PVC is one of the most hazardous kinds of plastic and used to be the second-most used plastic after polyethylene. It is mainly used to create toys, blood bags, loose-leaf binders, detergent bottles, and more.

Low-Density Polyethylene (LDPE)

A branch of the polyethylene family with a simple polymer chemical structure, making it less dense with heightened flexibility. It is common for grocery bags and hot beverage cups.

Polypropylene (PP)

This type of plastic is stiff and works well against heat. It is known for containing hot foods and drinks and is the safest plastic option for drinks and food.

Polystyrene (PS)

Another name for this type of plastic is styrofoam. The white material is flimsy, fragile, and used to create food containers, egg cartons, disposable cups, and bike helmets.


The final category exists for mixed plastics such as Polycarbonate (PC). It is associated with baby bottles, metal food cans, and dental sealants. Due to traces of Bisphenol A (BPA), PC is very toxic and banned in several countries.

How to identify different plastic types?

Now that we have listed the most common types of plastic in our everyday lives, how can we tell which one is which? What separates the safe types of plastic from the toxic ones?

Instead of making a visual judgment call, there are several methods that you can use to identify plastic types.

Marked symbols

The easiest way to identify plastic is by locating three arrows forming a triangle with a specific number in the middle. These international codes offer clarity to plastic identification based on chemical makeup and the grading for recycling.

Symbol 1 pertains to polyester and PET plastics. This category covers the most common plastic types and polyester fibers living in many households, including several articles of clothing, plastic bottles, and materials used for insulation.

Symbol 2 covers High-Density Polyethylene that is strong and resistant to acidic chemicals. This category includes bleach bottles, fuel tanks, and storage containers for motor oil.

Symbol 3 is for PVC items that can be both rigid and flexible. This category includes door and window frames, any sporting ball, water pipes, and the insulation for electrical wires.

Symbol 4 is Low-Density Polyethylene that is flexible and can change its shape without damage. This group contains products like grocery bags, shrink wrap, and juice and milk cartons.

Symbol 5 plastics are tough and flexible polypropylenes that can resist most acids and solvents. This category includes ropes, most beverage bottles, and plates and food containers that are dishwasher-proof.

Symbol 6 is for polystyrene that is stiff, rigid, and clearer than most opaque plastics. This includes CD cases, ballpoint pens, and many kitchen appliances and electronics casings.

Symbol 7 categorizes other plastic types such as acrylic, nylon, and polycarbonate. Most of these are not recyclable and combine with other polymers to create an assortment of plastic and fibers.


Another easy method to identify plastics is through appearance and feeling the material in your hands. Plastics that are polyethylene have a smooth texture and are flexible but can leave marks afterward.

Low-Density polyethylene is thin enough to crumble in the palm of your hands. If it crackles and makes a loud noise, that’s a clear sign of LDPE.

High-Density polyethylene is on the opposite spectrum of LDPE as it is tougher to deform. Most have a translucent and milky white coating, but uncolored HDPE is waxier in appearance.

Polypropylene has a flexibility that is bendable but will never break easily. Its resistance to fatigue makes it a reliable product container because it can take a lot of strain and deformation without leaving a single crack.

Polystyrene is recognizable and stands out from the rest of the plastic types. It is brittle and can break without much force. Although this type of plastic seems weak, it is resistant to impacts and provides extra cushion for most products.

Polyvinyl Chloride products feel soft, tough, and at times, sticky. The durability level ranges between the strengths of an LDPE and a PP product. It has higher transparency than other plastics, contains a glossy texture, and often appears yellowish.

The floating method

Another way to distinguish different types of plastics is by their density. The classification of products and their containment depends on the weight of certain plastics. Without an understanding of the density, it would be hard to tell what plastic would be good enough for what product.

The floating method can test the weight of various plastics by putting them in water and witnessing their buoyancy. Depending on whether they sink or swim will tell you which types of plastic have a higher density than others.

If you were to test this for yourself, you’d see how heavy most polyethylenes, polypropylene, and polyvinyl chloride is.

As the name implies, low-density polyethylene can remain above water, as well as polystyrene products.

The burning method

Different types of plastics experience a chemical reaction when they interact with heat. Not only do their appearances change, but they can also leave behind a unique smell.

Polyethylene and polypropylene are flammable plastics that will continue to burn even when the fire is out. Over time, the material starts melting and releases the smell of burning wax.

Polyvinyl is nonflammable and doesn’t keep the flame going on its own. Keep it heated long enough, and your nose will start to get irritated by the stench of chlorine. Also, since the flames have little effect, the material softens instead of melting.

Polystyrene is incredibly flammable and its smell, similar to burnt styrene, lingers after the fire is gone. The material softens after a while and produces a cloud of black smoke.

When the flames connect to these types of plastics, the color may change, giving you a strong interpretation of what plastic you’re handling.

A blue flame with yellow tips indicates Polyethylene burning, while yellow flames with green tips point toward PVC plastic.

Overall, we’d advise against using this method to identify plastic types as burning plastic can be harmful to both your health and the environment.

How different types of plastic affect the environment

While it is more convenient to have plastic in our everyday lives, remember that they also carry negative effects on our surrounding environment.

Plastic is non-biodegradable, meaning that it can’t decompose over time. On top of that, they are filled with harmful chemicals that seep into the landfill, soil, oceans, and any other location they are disposed to.

Plastics that can float or expose themselves to nearby animals can become harmful for them when consumed. Tossing away disposable bags, plastic straws, and bottles into the wild damages natural habitats and becomes a potential choking hazard for wild animals.

The production of plastic is also harmful to the environment as it releases a lot of fossil fuels into the world. About 8% of the world’s oil goes into the manufacturing of plastic, and that in turn is enough to destroy the surrounding ecosystem.

Finally, one of the most damaging aspects of plastics is the risk of microplastics leaching into the ground and water. These particles are microscopic and aren’t easy to recover. Not only can they destroy good soil and crops, but they are also toxic enough to do bodily harm if ingested.

Over time, many companies have started to adopt better practices and methods to protect the environment. With small improvements and conscious efforts to keep our surroundings clean, you too can prevent certain types of plastics from contaminating our homes and communities.

Final thoughts

When you learn how to identify different types of plastics, you gain practical knowledge of what is safe for your food and products. Some have the durability to bottle up harmful chemicals, and others are flexible enough to increase capacity.

Each type of plastic has its use and provides various roles in our everyday lives. It is also important to remember that some contain toxic chemicals and need to be carefully handled.

Second Life is one of the few companies dedicated to protecting the world from plastic toxicity. Our mission is to encourage companies to reduce plastic waste globally by helping them engage in plastic offset programs. You can learn more about our plastic offset program and case studies here.