Your Essential Guide to the 7 Types of Plastic

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Living in the Age of Plastic, it’s pretty tough to avoid it no matter how hard you try. The fossil fuel-derived substance is literally everywhere.

As a petrochemical, plastic is toxic just like its methane gas or crude oil raw materials. Sometimes less so, but still potentially very harmful to humans, marine life, and ecosystems under certain conditions. 

For example, plastics exposed to heat or sunlight could leach their toxic chemicals into food or water. Often, the leached toxins are additives or contaminants — not the plastic itself.

Scratched or worn plastic also releases these toxins more easily than virgin plastic. 

Most of the estimated 10 billion pounds of plastic on Earth so far winds up in waterways or landfills, largely unchanged from when it was first made. Some of it breaks down into tiny bits of microplastic, found in sea salt, seafood and fish, as well as vegetables that you consume. Ugh!

Or, plastic is burned in municipal incinerators — or out in the open in some Asian countries — adding toxic pollution to the air and contributing to our climate crisis. 

Would you believe that less than 10% of all plastic is actually recycled? Only two of the seven major types of plastic are regularly recycled today. It’s far cheaper to use fossil fuels, especially methane gas or petroleum, to just make more new plastic rather than recycle the old.

In this essential guide to the different types of plastic, you’ll discover the worst of the worst and what’s somewhat acceptable for certain safer uses. But ultimately, reducing or eliminating plastic from your life is a healthy goal — for you and the planet.

7 Types of Plastic: An Overview

Have you ever noticed the three triangular arrows with a number in their center on the bottom or side of a plastic package? (Sometimes, it’s just a triangle.) 

That number refers to the resin identification code (RIC). “Resin” is just another name for plastic.

Here’s a summary of plastic type codes presented in two different formats:

In all the plastic types, you notice the prefix “poly.” That’s chemspeak for many, referring to the arrangement of long chains of mostly carbon and hydrogen atoms in repeating units called monomers.

Monomers make up the polymers (a.k.a. plastics).

Taken one by one, here’s a comprehensive rundown of the most common types of plastic — including potential health effects, recyclability, uses, and environmental ramifications.

#1 Polyethylene Terephthalate (PET, PETE, or Polyester)

When you hear the term polyester, clothes or backpacks probably come to mind. But this word is also used for #1 plastic.

PET plastic is ubiquitous in single-use soft drink and water bottles. It’s usually clear or blue-tinted. (Note: Chemical leaching is more common with refilling the same bottle over and over again. Do not reuse #1 bottles.)

You can also find #1 plastic in supposedly microwavable or oven-safe food trays. However, many PET items contain a chemical called antimony trioxide, a known carcinogen (that is, a cancer-causing agent.) Heating PET containers could release it into food or water.

This plastic is one of the most recycled types of plastic, but only if it’s transparent. Colored plastic (all types) is difficult to recycle. So, please think twice before purchasing the bright green or red plastic bottle. It most likely will not be recycled. Plus, it will last 500+ years in a landfill or in a waterway unless it’s burned, in which case it contributes toxic gases to the air we breathe.

TIP: Remove caps (made of different plastic) before you put out your recycling bins for curbside pickup. Mixing plastic types intended for recycling is problematic, potentially jamming machines. The recycled mixed plastic material results in poorer-quality products that are undesirable, even for repurposing into lower-grade items like park benches or trash cans.  

#2 High-Density Polyethylene (HDPE, PE-HD)

Opaque milk jugs are one of the most common uses of #2 plastic. They’re also one of the most recycled items.

Made of a denser, more durable carbon-hydrogen polymer than #1, HDPE is also frequently used to make lightweight colored bottles for all kinds of personal care, cleaning, and laundry products.

You may also find #2 plastic in toys, crates, outdoor furniture, and similar items.

Research shows that HDPE — as well as all types of plastic — can leach hormone-disrupting chemicals, such as BPA or phthalates, into food or water. This is true even for those labeled as BPA- or phthalate-free. In some cases, in fact, BPA-free products released chemicals having more of an adverse hormonal effect than BPA-containing products!

Usually the leaching occurs when the plastic is exposed to UV light or high heat. Or maybe, the products spent months or years in storage—another situation when leaching is more likely. Do you know how long your plastic water bottles were housed in a warehouse or traveled in a truck before they got to you? Another reason to avoid them.

Take home message: To be safe, avoid consuming any food or water from plastic containers of any type. Especially avoid heating food or water in plastic.

#3 Polyvinyl Chloride (PVC, V)

Hands down, PVC is the most toxic of all types of plastic.

Plastic #3 is literally everywhere. 

It’s in toys, raincoats, rain boots, school binders, credit cards, shower curtains, vinyl seat covers, piping, wiring, flooring, replacement windows, food wrap, tubing, and medical (blood and IV) bags.

As its name indicates, the chemical chlorine is part of the structure of PVC, and its presence is a main reason that #3 plastic is so deadly during manufacture and disposal.

When it’s manufactured, dioxin and its chemical cousins — extremely carcinogenic chemicals — are produced as byproducts. These cancer-causing agents, as well as the toxic gas, hydrogen chloride, are released into the environment when PVC is burned at the end of its life.   

These chlorine-containing substances build up in fatty tissues in food webs all over the world. Sadly, due to how common #3 plastic is, it’s believed that every human carries a body burden of dioxins. 

To make PVC soft and pliable, plasticizers are added to it. The most common kinds of plasticizers constitute a large family of chemicals known as phthalates. 

Many countries have banned certain phthalates in a few products, like baby bottles, because they are hormone-disrupting substances. However, phthalates are still commonly used in all sorts of products today. They rub off easily when objects containing them are touched. Then, they’re readily absorbed by the skin and freely circulate in your bloodstream.

Very few recycling centers take #3 plastic because it is so toxic. Vinyl siding is the most common PVC material accepted at a few recycling centers. 

It can be overwhelming to try to get rid of all the PVC in your life, so don’t be afraid to start small. Possibly, start by opting for cloth bags and genuine rubber boots and toys instead of PVC-containing products. 

Buying pre-owned PVC items extends their life, prolonging the time before they are discarded. Although secondhand items may still contain PVC, at least they have had the chance to off-gas many toxics. This is especially important for babies, young children, and pregnant women.

Granted this is a small way people can keep fewer virgin plastics full of toxins from entering the market. But it’s a step in the right direction. 

Who knows? Your eco-conscious behavior may eventually influence others. Then everyone and the planet will breathe a little easier.

#4 Low-Density Polyethylene (LDPE, PE-LD)

If you’re like many people, you have a stash of #4 single-use plastic bags stored in a larger plastic bag or cabinet at home. They also decorate the landscape as wind-tossed artwork trapped in tree branches.

LDPE bags have become so noxious that many cities have banned them (or are trying to).

Considered safe for food use, you’ll find #4 plastic in sandwich bags, food wrap, coatings of paper milk cartons and coffee cups, squeezable bottles (like ketchup or honey), produce bags, and carryout food container lids. However, some research questions just how safe #4 plastic really is to humans. (Think hormonal disruption.)

Some grocery stores collect clean #4 plastic like: single-use store bags, film wrappings, mailers, newspaper bags, dry cleaning bags, bread bags, and similar items intended for recycling. Whether they are actually recyclable or not is debatable, but How2Recycle does. Contact them to find a location near you. 

Being so thin, LDHE plastic frequently jams up recycling machines so it’s not usually collected. Do not put any #4s in your regular curbside recycling pickup.

#5 Polypropylene (PP)

Do you know that polypropylene is highly regarded as an effective material for face masks against Covid-19? It’s also used in long underwear for its heat-trapping and moisture-wicking properties.

#5 plastic is common as a reusable water bottle material. You can also find it in food storage bowls, yogurt containers, margarine tubs, straws, disposable diapers and sanitary napkins, single-use cutlery and plates, medicine bottles, carryout food containers, DVD cases, car parts, carpet, and rope. 

Like #4 plastic, PP is considered safe for food and beverage contact. In fact, the #5 symbol is associated with “microwave-safe.” But does that refer to the container or to your health?

For sure, the term implies that the product won’t melt, warp, or form interior bubbles. Whether it also means it won’t leach chemicals that can upset your endocrine system is debatable.

Studies cast doubt on the safety of all plastic — including PP’s safety. It’s prudent not to consume food that’s been heated in plastic. Better safe than sorry. 

#6 Polystyrene (PS)

After PVC, polystyrene is next in line for the most toxic type of plastic.

Very difficult and costly to recycle, #6 plastic is made up of styrene, a very toxic substance and likely carcinogen. Styrene is made with benzene, another cancer-causing substance.

Some styrene is present in cigarette smoke, building materials, and photocopier operating vapors. It can leach into food and beverages, too, especially when hot or oily. 

There are types of #6 plastic produced using hydrofluorocarbons (HFCs) — potent greenhouse gases that are much worse than carbon dioxide as climate-destroying chemicals.

Polystyrene resists breakdown in the environment. Maybe you’ve seen the “snow” floating on lakes or rivers? The noxious, toxic litter of #6 plastic is a big reason why many cities and towns ban it.

When you crush PS plastic, ozone-destroying HFCs are released. Ouch!

Polystyrene comes in many forms. Styrofoam is a brand name example of #6 plastic. The squeaky white coffee cups, coolers, egg cartons, building insulation materials, packing material “bricks,” and carryout food containers are the most well-known examples.

#7 Other (O)

 Everything else not listed above is put into this “grab bag” category called “other.” Bioplastics fall in this group. So, too, do items containing more than one plastic type.

As you can guess, nothing in group #7 is easily recyclable.

Most of #7 is polycarbonate plastic made of BPA or related substances. These chemicals interfere with normal sexual and reproductive development. BPA is banned in several products including baby bottles for this reason.

Polycarbonate plastic is common in sports bottles and equipment, CD cases, Covid-19 face shields, car parts, and dental sealants.

Other types of plastic belonging to this group include PLA (a bioplastic), ABS (3D-printing), and PMMA (acrylic). 

Bottom Line on Types of Plastic

It’s commonly believed that plastic #1, #2, #4, and #5 are relatively safe for people and the environment. This is true when comparing them to plastic #3, #6, and #7.

However, studies show that all forms of plastic — those containing BPA as well as those that don’t — have hormone-disrupting characteristics to some degree. Or, results are varied or inconclusive.

To err on the side of caution for personal and planetary well-being, reduce or eliminate all plastic from your life, but especially for foods and beverages. Fortunately, there are plenty of non-plastic alternatives on the market today.

Where to Find Plastic-Free Alternatives

Especially if you’re just starting out, reducing the amount of plastics in your life can be overwhelming. Remember to take it one step at a time and be patient with yourself as you adjust your lifestyle. 

Here are a few recommended stores where you can find plastic-free alternatives for many common household and personal care items.

• Life Without Plastic
• EarthHero
• Simply Zero
• Etee (code: THEFILTERY for 10% off)