Is number 2 plastic recyclable? 

Number 2 plastic is known as High-Density Polyethylene (HDPE), it’s made from the monomer ethylene. Ethylene is an organic chemical derived from petroleum. HDPE is a versatile plastic with unique physical attributes that make it extremely valuable. 

The 2 in the cyclical arrow refers to the resin identification number of HDPE, which implies the resin used to make plastic 2 products is HDPE.

Number 2 plastic, HDPE,  has high impact resistance, melting temperature, tensile strength, and strength to density ratio; these properties diversify the applications of HDPE. 

HDPE is durable and lightweight plastic, its usefulness makes it hard to ban, however, this article will explain what HDPE is, how its use can be minimized, whether it’s recycled, how sustainable this material is, and what impacts it has on the environment. 

Is number 2 plastic (HDPE) recyclable?

Yes, it is 100% recyclable. Most curbside recycling systems accept HDPE. After Polyethylene terephthalate (PET), HDPE is the most recycled plastic. 

Most municipalities, counties, and cities recycle HDPE. The general recycling systems (curbside recycling) in most cities accept HDPE. Make sure you find out whether your city has a single-stream or a multi-stream recycling system. 

You can throw out your plastic waste into the general curbside recycling bin in the US, but make sure you throw it in the bin labeled “Plastic” in Europe, as it has a multi-stream recycling system. This means improper disposal will lead to the material being thrown into the trash. 

What is number 2 plastic? 

Number 2 Plastic (HDPE/PEHD) is a synthetic polymer made from ethylene monomers; ethylene is a hydrocarbon extracted from crude oil. 

The resin identification number of HDPE is 2, hence the 2 in the recycling sign. 

The dense nature of HDPE derives from its polymer chains not branching out; HDPE has linear polymers. 

HDPE is extremely useful due to a list of its physical properties. It has high tensile strength, melting temperature, malleability in its liquid form, resistance to corrosion, density to weight ratio. These attributes make it an excellent candidate for a list of applications.  

What is HDPE used for? 

The useful properties listed above makes HDPE ideal for,

  • Making ropes due to their high tensile strength. This essentially means it has higher elasticity and does not snap when weight is applied.


  • Making pavement and rooftop tiles. Once it is melted it is extremely malleable yet when it cools down it maintains its shape. It can also withstand incredible pressure, this is why it is the primary ingredient in making tiles.
  • Making food containers. HDPE is resistant to heat and is non-toxic. This is why it is such a popular plastic for food packaging and reusable food containers.


  • Making water pipes. It is very resistant to corrosion and harsh chemicals such as acids and bases, it does not rot or collect mildew, it is mold resistant as well. These attributes make it ideal for making water pipes in households.

How to recycle plastic 2 (HDPE):

Before you give away materials made of plastic 2 for recycling, make sure to wash them thoroughly. Also, properly empty the water and soda bottles before discarding them. It is very important to remember to wash all food and grease from food containers before recycling. These contaminants are not tolerated in materials recovery facilities (MRF)s, and all dirty items are thrown into the garbage. 

While recycling, make sure the plastic bag you put all the plastic in is not tied up. Tied bags mostly get thrown into garbage since the sorting takes place manually by workers. 

HDPE-based shopping bags are still very common. Keep in mind that soft plastics like shopping bags are not usually recycled. Check your guidelines before throwing them in the recycling bin. 

In most cities, soft plastic is not accepted for recycling. Soft plastic is anything that scrunches up in your fist. They are usually not recycled because they are too light and hard to manage in recycling centers. These bags could potentially fly into the machinery and cause damage. 

As for other items made of HDPE, they are mostly recycled. 

How is HDPE recycled? 

HDPE is a thermoplastic, which means it can be melted and molded into new shapes. This is the key characteristic that allows it to be recycled. The process by which most HDPE is produced is called thermo-mechanical recycling.  

The plastic is first moved to a materials recovery facility (MRF). Here these plastics are first put into bales. Then these are transported to recycling centers. 

HDPE has multiple grades, these are based on the thickness of the plastic. Thicker plastics are better grades. After sorting, the plastic is thoroughly cleaned with water and detergent.

Then it’s shredded. Once shredded, the plastic is passed into an extruder which melts the plastic and then creates pellets out of them. 

These pellets are the final product which is then shipped to a manufacturing plant where they can be melted and molded into a variety of products. 

How HDPE waste affects the environment: 

Our media is inundated with news about how plastic is slowly killing the environment. Sometimes literally, ill-disposed plastic is often ingested by avian or aquatic species. These plastics lodge into their stomachs, cause internal damage, or simply block the digestive tract of the animal. These animals then die slow and tragic deaths.

Proper management of plastic waste is of utmost importance. HDPE is relatively easy to recycle, yet no more than 30% of HDPE is recycled, the rest ends up in landfills or are incinerated. 

Poor disposal of these plastics allows these to end up in our oceans, resulting in marine life being affected as explained above. 

Incineration is also not the best way to dispose of HDPE as it releases carbon into the atmosphere. In countries where these plastics are burned in the open air, residents who live near these sites have developed severe breathing issues because of it. 

Burning plastic in the open air creates soot which is extremely toxic and can cause cancer and lung issues in people who inhale it for prolonged periods. 

To reduce HDPE waste, legislative changes need to take place. More efficient recycling systems and newer techniques that put HDPE into a closed-recycling loop are necessary. 

How to improve the recycling system for HDPE: 

The best approach we can take to improve HDPE recycling is to improve the collection process for recycling and implement more sustainable methods to recycle HDPE. 

Proper management of plastic waste is of utmost importance. HDPE is relatively easy to recycle, yet no more than 30% of HDPE is recycled, the rest ends up in landfills or are incinerated. 

Incineration is criticized by environmentalists as an imperfect method to dispose of plastic waste. This process releases massive levels of carbon into the atmosphere and contributes to global warming. 

Pyrolysis is one such method, it is a type of chemical recycling, where HDPE is heated in an oxygen-deprived chamber with some catalysts to convert it back to its monomer. This monomer then can be reused to make HDPE. This puts HDPE into a closed-loop-recycling system. 

To reduce HDPE waste, legislative changes need to take place. More efficient recycling systems and newer techniques that put HDPE into a closed-recycling loop are necessary. 

Can HDPE be sustainable? 

There has been a shift in focus from a linear economy to a circular economy in recent years. If we can successfully enter HDPE into a circular economy then there is no need to ban it.

Recycling alone, specifically mechanical recycling is not the answer. HDPE can be recycled around 10 times before its quality deteriorates. 

This means once it is recycled for the 10th time, it’ll end up in the landfills. Pyrolysis can be the way out here, converting this HDPE back into ethylene and consequently using this ethylene to remake HDPE which is of virgin quality creates the perfect loop. 

Currently, multiple hurdles keep chemical recycling from being implemented on a mass scale. As things stand now, virgin HDPE is very cheap, this deters companies from investing in recycled HDPE. 

The only way chemical recycling will be successful is if there are subsidies provided to companies that perform this technique. 

Legislation can change this and shift toward the use of recycled HDPE.

One thing is certain, for the time being, the best solution is to reduce the use of HDPE while we look for ways to recycle it with better efficiency. 

Conclusion: 

Number 2 plastic, HDPE,  has high impact resistance, melting temperature, tensile strength, and strength to density ratio; these properties diversify the applications of HDPE. 

HDPE is durable and lightweight plastic, its usefulness makes it hard to ban, however, this article explains what HDPE is, how its use can be minimized, whether it’s recycled, how sustainable this material is, and what impacts it has on the environment. 

Frequently Asked Questions (FAQs): Is number 2 plastic recyclable? 

What does the number 2 in plastic 2 refer to? 

The numbers on a plastic container enclosed in circular arrows refer to the resin identification number of the plastic. Each number represents a different plastic type. 

What is plastic 2? 

Plastic 2 is known as high-density polyethylene (HDPE). It is made from a petrochemical named ethylene. 

Is HDPE  useful?

Yes, it is a very useful plastic. It is resistant to corrosive chemicals, heat, pressure, and has a high weight to density ratio. Additionally, it has a  very high tensile strength and is very lightweight and non-toxic. These properties qualify it to be used for making a host of products from pavement tiles, underground water pipes, ropes, food containers, water bottles, plastic shopping bags, etc. 

Is plastic 2 bad for the environment? 

Yes, as things stand, more and more virgin HDPE (plastic 2) is being made each day instead of recycling the already available post-consumer HDPE. This increases carbon emission, energy and fossil fuel expenditures, plastic waste, and air pollution. 

Lastly, HDPE does not degrade and remains on the ground for centuries, overtime breaking down into smaller pieces of HDPE. 

Is HDPE environmentally friendly? 

No, not as things stand. It is not biodegradable, so it remains in landfills for centuries. With time it breaks down into smaller HDPE pieces. Animals near landfills or aquatic creatures ingest these small plastics, these lodge in their insides, and these creatures often die slow painful deaths. 

Can you recycle HDPE? 

Yes, it is recyclable. It is mostly recycled by a thermomechanical method, however, it is also recyclable by a chemical method where it is broken down to its base molecules. 

How do you recycle plastic 2? 

Plastic 2 is recycled by a thermomechanical technique where the plastic is shredded, melted, and then turned into pellets. 

Is HDPE biodegradable? 

No, it is not biodegradable. It can remain in landfills for centuries. 

Is HDPE food safe? 

Yes, it has a very high melting temperature and does not release toxic chemicals, making it ideal for reusable food containers.

Reference: 

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  3. HDPE Plastic Recycling – How is HDPE Recycled?. (2022). Retrieved 10 January 2022, from https://www.plasticexpert.co.uk/plastic-recycling/hdpe-plastic-recycling/
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  6. All About HDPE Recycling: What Are HDPE, Benefits, How to Recycle & More. (2022). Retrieved 10 January 2022, from https://www.aaapolymer.com/hdpe-recycling/
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  8. Loultcheva, M., Proietto, M., Jilov, N., & La Mantia, F. (1997). Recycling of high-density polyethylene containers. Polymer Degradation And Stability, 57(1), 77-81. DOI: 10.1016/s0141-3910(96)00230-3
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