The Chemicals in Plastic and Why it Matters, Part 2

Colorful plastic litter organized by color on a beach.
Image by Filmbetrachter from Pixabay

Plastics are made from chemicals and petroleum, which you read about in Part 1 of this series. Today, I want to tell you about the chemical contents of plastics by resin code, the number on the bottom surrounded by a triangle. More importantly, I want to inform you of the ways they may be toxic to our health.

Resin Identification Codes (RICs)

Resin symbol for #1 plastic, or PET.
Image by OpenIcons from Pixabay

The plastics industry created RICs in 1988 as part of their campaign to boost plastic’s image. They even lobbied to have state legislatures adopt them. But this little symbol on almost all plastic packaging is misleading. Many assume that the recycling symbol or RIC means that a package is automatically recyclable. However, that is not true, it actually only refers to the type of plastic resin used.

To reduce confusion, ASTM, the organization that regulates the RIC system, updated the symbol from the chasing arrows to a solid triangle in 2013. “However, manufacturers aren’t required to change their equipment to incorporate the new symbol, which is why you still see the arrows on many plastic products,” according to an article on Oceano.org.1 So it’s still easy for people who don’t know to mistake the RIC as a recycling symbol versus an industry tag for the plastic.

Graphic comparing the types of recycling symbols used with RICs.

A clear plastic PET food container showing the updated symbol, a numbe 1 inside of triangle.
Example of a plastic PET food container showing the updated symbol. Photo by me

The RICs / Types of Plastics

Resin Identification Coding System graphic
Image courtesy of Wikimedia Commons

Next, let’s look at the 7 RICs and types of plastics, what they are used for, their characteristics, their chemical contents, and their potential toxicity. Note that this is not an exhaustive list; nor is each category exhaustive in the standard products or characteristics.

#1 PET/PETE: Polyethylene terephthalate

Standard products: Water bottles, soda bottles, food containers such as cooking oil and peanut butter, wrinkle-proof clothing, fleece blankets, padding in pillows and comforters, carpeting, other polyester fabrics.

About: PET is the most valuable type of plastic and the most recycled. There are typically two types: one is made with a blow molding machine; the other is thermoform which is made by heating a plastic sheet until pliable and then molded into a specific shape. The main difference is in molecular weight. Higher molecular weight items, such as bottles and jugs made from blow molding, are more valuable than their thermoform counterparts. Thermoform, though more difficult to sell, is often recycled into carpeting.2

Chemical content: “A chemical called antimony trioxide is used as a catalyst and flame retardant in making PET, and this antimony additive is considered a possible carcinogen.” The amount in one single water bottle is minimal, but leaching increases with heat. Think of those water bottles stored in the car during the summer. “There is research showing that PET may leach phthalates too, even though the plastics industry says that phthalates are not required to make PET.”3 Regardless, think about switching to metal or glass containers whenever possible.

Close-up of clear blue water bottles
Image by pasja1000 from Pixabay

#2 HDPE: High-density Polyethylene

Standard products: Milk jugs, water bottles, juice, bottles, bleach, dish and laundry detergent bottles, shampoo and conditioner bottles, cleaner containers, over-the-counter medicine bottles, cereal box liners, Tyvek home insulation, plastic-wood composites, snowboards, 3D printing filament, and wire covering. It is even used in some plastic surgery procedures.

About: This is one of the most widely used plastics because of its versatility. It is strong, flexible, cost-effective, moisture-resistant, and resistant to most chemical solvents. It has high tensile strength and has both a high-impact resistance and melting point. “The polyethylene polymer has the simplest basic chemical structure of any polymer, making it easy to process and thus extremely popular for low value, high volume applications.”4

Chemical content: While this is considered a ‘safer’ plastic for food and drink use, there is evidence that these release endocrine-disrupting chemicals, especially when exposed to UV. “The main leaching culprits are estrogen-mimicking nonylphenols and octylphenols, which are added to polyethylene as stabilizers and plasticizers.”5 Those chemicals disrupt the body’s hormones and can cause cancer, reproductive problems, birth defects, and other developmental disorders.

Angled photo of plastic milk jugs at the supermarket.
Milk jugs are typically #2 HDPE. Photo by me

#3 PVC: Polyvinyl Chloride

Standard products: Think all vinyl products. Shower curtains, medical bags, medical tubing, shrink wrap, children’s toys, binders, school supplies, plastic furniture, garden hoses, vinyl clothing and outerwear, wire and cable insulation, vinyl records, carpet backing, flooring, credit cards, clamshell packaging, plumbing pipes, vinyl siding, window frames, fences, decking, other construction materials.

About: “PVC can take on a staggering variety of personalities – rigid, filmy, flexible, leathery – thanks to the ease with which it can be blended with other chemicals.”6 PVC is versatile as it can be adapted to many applications depending on the plasticizing additives. It is strong and resistant to moisture and abrasion. It can be produced clear or colored. About three-quarters of all vinyl produced goes into construction applications.

Chemical content: PVC is known as the poison plastic because it leaches toxins for its entire life cycle and should be avoided whenever possible. Vinyl is manufactured by polymerizing a chemical called vinyl chloride. It can contain up to 55% additives, mainly phthalates. The chemicals it may release during its lifetime include cancer-causing dioxins, endocrine-disrupting phthalates, bisphenol A (BPA), lead, mercury, cadmium, and other heavy metals. “The problem with PVC is that its base monomer building block is vinyl chloride, which is highly toxic and unstable, thus requiring lots of additives to calm it down and make it usable. But even in its final ‘stabilized’ form, PVC is not very stable.”7 The additives leach out and you can inhale and ingest them.

White PVC pipes stacked at a manufacturer or store.
PVC pipes, photo by Dennis Hill on Flickr, Creative Commons license (CC BY 2.0)

#4 LDPE: Low-density Polyethylene

Standard products: Film applications like bags, such as those used for bread, shopping, dry-cleaning, newspapers, frozen foods, produce, and garbage. Also used for shrink wraps, linings for cartons and cups, container lids, some squeeze bottles, orthotics, and prosthetics.

About: LDPE is a soft, flexible, lightweight plastic material, known for its low-temperature flexibility, toughness, and corrosion resistance. But it is not recyclable in any practical sense. Citing data from the Environmental Protection Agency (EPA), one large recycling corporation noted that “the overwhelming majority of products made from LDPE end up in landfills…Dumping tons of LDPE in landfills can have devastating consequences…plastic buried in landfills can leach into the soil and introduce chemicals into the groundwater.” They can threaten marine life in coastal areas, and “lightweight plastic bags can be blown great distances by the wind, ending up in bodies of water where animals eat them or become tangled in them.”8 Plastic bags causes huge environmental problems.

Chemical content: These can leach some of the same chemicals as #2 HDPE plastic. It is a thermoplastic made from the polymerization of ethylene. While ethylene is considered a building block of plastic, it is highly flammable and reactive. It is created by Ethane Cracker Plants, which use an environmentally questionable process to extract the ethane to make ethylene. While difficult to avoid, steer clear of this plastic whenever possible.

Angled photo of the bread aisle at the supermarket.
Bread bags are typically #4 LDPE. Photo by me
Blue plastic cap from a gallon milk or water jug, #4 LDPE plastic.
Blue plastic cap from a gallon water jug, #4 LDPE plastic. Photo by me

#5 PP: Polypropylene

Standard products: Polypropylene is used in packaging, yogurt cups, sour cream and soft cheese containers, prescription bottles, butter/margarine containers, plastic to-go containers, leftover containers, freezer meal containers, the filter cases of some disposable home water filters, electrical wiring, and plastic bottle caps because polypropylene can withstand pressure. It is also used in vehicles for bumpers, carpets, and other parts. Polypropylene allows moisture to escape and stays dry, making it ideal for use in disposable diapers.

About: Polypropylene is sometimes referred to as the “safe” plastic, but there really is no safe plastic when it comes to food. All plastic has the capacity to poison us in certain circumstances. Polypropylene is a stronger plastic than other types, but it is generally not recyclable because there isn’t sufficient reprocessing capacity. Polypropylene is more stable and resists heat better than other plastics. So it is generally considered safer for foods and hot liquids because it leaches fewer chemicals (though it still does leach, which is why you should use glass or metal containers for your food).9 However, this is what many leftover and freezer meal containers are made from. Have you ever noticed rough patches or surface defects in your leftover containers? Any disruptions on the surface mean the polypropylene has been compromised, which increases the chances that it will leach chemicals into your food, especially when heating it.

If you have polypropylene leftover containers from before 2013, replace them. These contained phthalates and bisphenol A (BPA). And if you do replace them, please buy stainless steel or glass containers and just avoid the chemicals in plastic altogether.

Chemical content: Polypropylene is a rigid and crystalline thermoplastic made from the polymerization of the propene monomer. There is ongoing research about the health effects of certain additives leaching from polypropylene, such as oleamide, a polymer lubricant and a bioactive compound. Oleamide does occur naturally in the human body, but the long-term effects of synthetic oleamide are not yet known. In a 2021 study entitled “Plastic additive oleamide elicits hyperactivity in hermit crabs,” scientists found that it may be perceived as a feeding cue by marine species, thus increasing the consumption of microplastics.10

Angled photo of the yogurt shelves at the supermarket.
Yogurt and other dairy containers are typically #5 polypropylene. Photo by me

#6 PS: Polystyrene

“Most recognizable when puffed up with air into that synthetic meringue known technically as expanded polystyrene and popularly by the trademark Styrofoam.” -Susan Freinkel, author of Plastic: A Toxic Love Story11

Standard products: The foam form, called Expanded Polystyrene (EPS), also known as Styrofoam, is used in egg cartons, meat trays, single-use food and take-out containers, coffee cups, vehicles, bike helmets, packing peanuts, and home insulation. The rigid form is used for single-use food containers, cutlery, CD and DVD cases, disposable razors, etc. “It is also combined with rubber to create an opaque high impact polystyrene used for model assembly kits, coat hangers, electronic housings, license plate frames, aspirin bottles and medical and lab equipment, including test tubes and petri dishes.”12

About: It may be difficult to avoid this stuff in home insulation, vehicles, and bike helmets, but it should be avoided at all costs when it comes to food and beverages. I wrote a lot about polystyrene in my series on Styrofoam and polystyrene food containers. These containers and cups leach styrene into food and beverages and thus enter your body. Styrene is known to likely be carcinogenic. It is considered a brain and nervous system toxicant and causes problems in the lungs, liver, and immune system.

Chemical content: Polystyrene is a synthetic polymer made from the polymerization of styrene. It is a chemically produced plastic that can be made into a hard or foam plastic. The foam is created by expanding the styrene by blowing various chemical gases into it. Polystyrene is made from ethylene and benzene, both hydrocarbons derived from by-products of petroleum and natural gas (also known as petrochemicals).

Take-out in polystyrene containers
Image by albedo20 on Flickr, Creative Commons license (CC BY-NC-ND 2.0)

#7: OTHER Plastics

This is the catch-all category for all ‘other plastics.’ Any plastic items not made from the above six plastic RICs are grouped together as #7’s. These include acrylic, nylon, polycarbonate, epoxy resins, polylactic acid (PLA), and multilayer combinations of different plastics. These are never recyclable except through a few rare and expensive take-back programs, because of the vast array of resins and chemicals mixed together. Below are some of the individual plastic types that fall under #7.

Acrylic: This is a rigid thermoplastic that is strong, diverse, and resilient; and it can be clear or solid colored. Acrylics are used to make bulletproof windows, LEGOs, dental fillings and dentures, airplane windows, aquariums, shower doors, vehicle parts, helmets, and even textiles such as clothing, tents, and sails. This is a stable plastic and is considered a ‘safer’ plastic, except for certain ones used in dental applications. Those, specifically acrylic methacrylate resins, are suspected to be cytotoxic (toxic at the cellular level) because they leach chemicals such as formaldehyde and methyl methacrylate.13 That being said, keep those LEGOs out of your toddler’s mouths.

Red, blue, white, yellow, and black Legos in a small pile.
Photo by Alexas_Fotos on Pixabay

Nylon: This belongs to a group of plastic resins called polyamides that include Kevlar and Velcro. Invented by DuPont in the 1930s, nylon was originally invented to be a synthetic alternative for silk, for example, stockings. Nylon can be fiber, solid, or film. Items made from it include clothing, toothbrush and hairbrush bristles, rope*, instrument strings, tents, parachutes, carpets, tires, food packaging, boat propellers, skateboard wheels, and mechanical and automotive parts.

DuPont advertisement for Nylon from 1949, showing woman pulling up her Nylon stockings.
DuPont advertisement for Nylon from 1949. Image by clotho98 on Flickr, Creative Commons license (CC BY-NC 2.0)

*NOTE: Most rope and nets used in commercial fishing are made from nylon and present a huge problem in the oceans. The rope and nets break away from the fishing vessels and become threats to fish, sea turtles, and marine mammals who get entangled in them. Since nylon is plastic, it will not decompose and will remain in the ocean for decades or longer.

Seal on beach with nylon fishing net entangled around its neck.
Nylon fishing net entangled around the neck of a seal. Image by Noutch from Pixabay

Polycarbonate: Originally designed as an engineering plastic to compete with die-cast metal and substitute glass because it is lightweight, strong, transparent, and shatter-proof. In the past, it was used in reusable water bottles and baby bottles until bisphenol A (BPA) was ruled toxic. “It is still a favorite for rigid products including CDs and DVDs, eyeglass lenses, dental sealants, lab equipment, snowboards, car parts and housing for cell phones, computers and power tools.” It is also still used in the large, blue water containers common in offices.14 This type of plastic is good for items not related to food or beverage. However, we should use it less overall in other applications when possible to reduce waste, because when polycarbonate breaks it cannot be recycled.

Epoxy resins: Known for high strength, low weight, temperature and chemical resistance. Used in many applications: high-performance adhesives, coatings, paint, sealant, insulators, wind turbine blades, fiber optics, electrical circuit boards, and parts for carts, boats, and planes. They are also used on the interior lining of most canned goods. Avoid these when possible, especially with food and beverage containers because they contain chemicals such as bisphenol A (BPA) and epichlorohydrin. The latter likely causes blood, respiratory, and liver damage and is a probable carcinogen.15

Polylactic Acid (PLA): This is a bio-based plastic made from lactic acid, which is a fermentation product of corn or cane sugar. This is the most common bioplastic, used in a variety of products including clothing, bottles, weed cloth, gift and credit cards, food packaging, diapers, wipes, and disposable dishes. PLA is advertised as compostable but it is only biodegradable under industrial composting conditions, which is still largely unavailable.16

Polyurethanes

This large family of plastics was introduced in 1954. Polyurethanes do not have an assigned RIC, but they are worth mentioning because they are so common. They come in foamed versions that are soft and flexible for uses in mattresses, cushioning in furniture, cars, and running shoes, spray foam insulation, and carpet underlay. They can take on a flexible form for hoses, tubing, gaskets, seals; and they can be tough and rigid for items such as insulating lining for buildings and refrigerators. Polyurethane can also be made into thin films or coatings, such as adhesives for food packaging and waterproof coatings for wood. When it is spun into fibers, it makes Spandex, Lycra, and even latex-free condoms.17

Polyurethane is made from isocyanates, a chemical that is potentially toxic, as it is the leading cause of occupational asthma. “As for our day-to-day use, polyurethanes have also been linked to a skin irritation known as contact dermatitis through direct contact with such polyurethane items as a toilet seat, jewelry and Spandex tapes sewn into underwear.” It is highly flammable and may contain flame retardant additives that go in mattresses and spray foam insulation. Flame retardants are full of chemical combinations that are considered trade secrets, so the public does not know what potential toxins are present in their items. Spray foam insulation, even once cured, can off-gas isocyanate methylene diphenyl diisocyanate (MDI), which has been linked to asthma and lung damage.18

Person in white Hazmat suit applying purple spray foam insulation.
Image by justynkalp from Pixabay

What You Can Do

The best thing you can do is to keep learning, which you’re already doing if you’re reading this article. Stay informed and be aware of what chemicals you’re exposed to through plastics, packaging, and additives. Avoid those which are documented as toxic or even potentially toxic. Additionally, remember that few plastics are actually recycled, so reducing the plastics you purchase is essential to the environment and your health. Thank you for reading, please share and subscribe!

“We all need to separate the hopeful and increasingly fantastical act of recycling from the reality of plastic pollution. Recent data indicates that our recycling wishes, hopes, and dreams – perhaps driven in part by myths surrounding RICs – will not stop plastic from entering our oceans. Instead, if we truly want to protect the environment and marine life, we need to campaign for more plastic-free choices and zones, and for the reduction of plastic production and pollution.”19

 

Additional Resources:

11 Ways to Go Plastic-Free with Food

To learn more about Bioplastics: The Packaging Industry and How We Can Consume Differently, Part 3

The different types of plastics used in packaging: Guide to my Packaging Industry Series

More about polystyrene #5: Guide to my Styrofoam and Polystyrene Containers are Poisoning Your Food Series

Footnotes:

The Chemicals in Plastic and Why it Matters, Part 1

Colorful plastic bottles, from products such as shampoo and household cleaners.
Image by ds_30 from Pixabay

Plastics are made from chemicals and petroleum.

I have found that most people don’t know that, or don’t care to know. Many plastics are full of potentially toxic chemical concoctions, and knowing what makes up plastics is key to understanding how dangerous those chemicals are. Once you know that, it’s hard to understand why would the FDA, EPA, and other government regulatory agencies allow them to be used in, well…everything.

The short answer is, they just don’t regulate that many chemicals.

But plastics are all around us in everyday life, and thus we are regularly exposed to these chemicals. This is one reason I’m anti-plastic, at least in the way we overuse and overconsume it in daily life.

How Plastic is Made

Colorful plastic nurdles close-up.
Plastic nurdles. Image by feiern1 from Pixabay

“Most plastic is derived from oil drilling and/or fracking.” -Jennie Romer, sustainability expert and attorney1

Plastics are derived from fossil fuels, such as crude oil and natural gas. It is then processed at a refinery into ethane and propane. Next, they go to what are called cracker facilities that “crack” or break down these molecules. They turn ethane into ethylene, which is a building block of most common plastics. Propane becomes propylene. They are mixed with a catalyst, or chemical additive, that links the molecules together and forms polymers. Polymers are long, repeating chains of molecules that are chemically linked, or bonded, together. Harken back to chemistry class and this process is called polymerization.

But “polymers alone rarely have the physical qualities to be of practical value, so most plastics contain a multitude of chemical additives to facilitate the manufacturing process or produce a particular desirable property, such as flexibility, toughness, color or resistance to UV light.”2 This process forms different resins, or types of plastics, and are generally categorized by Resin Codes (those little numbers on plastics with the recycling symbol around it).

Oil pump with bright blue sky and white clouds background
Image by John R Perry from Pixabay

Plastic is Toxic

These chemical additives are usually what is most harmful to our health and the environment, as they leach over time and under certain conditions such as heat or UV exposure. Additives include dyes, “fragrances” or phthalates, plasticizers such as bisphenol A (BPA), fillers, fluffers, hardeners, stabilizers, lubricants, fire retardants, blowing agents, antistatic chemicals, and even fungicides and antibacterial agents. “Imagine that, plastics eerily designed to repel insects and bacteria, just like genetically modified cotton or corn!” wrote Chantal Plamondon and Jay Sinha, founders of Life Without Plastic.3

Many chemicals are not even regulated. For example, the FDA banned BPA from infant formula packaging, baby bottles, and sippy cups in 2013 because of its toxic leaching. But, there is a whole family of other bisphenols and most of those are still in active and legal use.

Plastic is often intended for single use only because the toxins leach out over time into your water, food, or product. As Chantal Plamondon and Jay Sinha noted: “We would wash and reuse single-use water bottles over and over, thinking we were being super eco-aware by preventing them from being recycled after a single use or heading straight into the trash and, ultimately, a landfill. We didn’t realize each use and wash was breaking down the cheap, unstable plastic more and more, and increasing the potential for chemicals and microscopic bits of plastic to leach into our drinks.”4 I used to reuse my plastic water bottles too – and I stored mine in the car, where the plastics were exposed to intense heat and sunlight, both factors that accelerate plastic chemical leaching.

Plastic Marketing

Plastic toy cash register, plastic coins and pretend bills
Image by anncapictures from Pixabay

Facing changing public opinion about the harmfulness of plastic in the 1980s, the plastics industry “launched a $50M-a-year ad campaign to improve plastic’s image. Part of the message was ‘recycling is the answer.’ Within the plastics industry, however, it was later revealed that even then there was serious doubt that widespread plastic recycling could ever be made economically viable.”5 They knew then, and they certainly know now, that we cannot recycle all of the plastic. Despite the pollution and toxicity, the plastics industry continues to push, market, and produce excessive plastic products and packaging.

“If the public thinks that recycling is working, then they’re not going to be as concerned about the environment.” -Larry Thomas, former head of the Society of the Plastics Industry, now called the Plastics Industry Association6

There are many advocates for plastic production, including the chemical, trade, and petroleum organizations. The global plastics industry is worth between $500 and $800 billion dollars. The plastics industry is not going away while there is that much money at stake.

The American Chemistry Council (ACC) is one of the biggest supporters of plastics, and they spend millions each year contributing to political parties in order to fight legislation that would regulate plastic production. Other organizations protective of plastics include (but are not limited to) the Plastics Industry Association, the American Chemical Society, the Manufacturers Association for Plastic Processors, the International Association of Plastics Distribution, the Vinyl Institute, the American Fuel & Petrochemical Manufacturers, and the Society Of Plastics Engineers.

Plastics Make it Possible Logo, an American Chemistry Council initiative.
Plastics Make it Possible Logo, an American Chemistry Council initiative.

“We are not out to destroy the plastics industry, but we must embrace change.”7

The Overproduction of Plastic

Greenpeace scuba diver holding up a Coca-Cola bottle and sign: "Coca-Cola is this yours?" Found in the Great Pacific Garbage Patch.
A Greenpeace diver holds a banner reading “Coca-Cola is this yours?” and a
Coca-Cola bottle found adrift in the garbage patch. The crew of the Greenpeace ship MY Arctic Sunrise voyage into the Great Pacific Garbage Patch document plastics and other marine debris. CREDIT: © Justin Hofman / Greenpeace, October 1, 2018. Image used with written permission from Greenpeace media.

“Many of these products, such as plastic bags and food wrappers, have a lifespan of mere minutes to hours, yet they may persist in the environment for hundreds of years.”8

There are a few plastics that have an important place on our planet and in our lives, but most do not. Single-use disposable plastics are the major culprits of our plastic pollution problem. The companies we purchase products from are now producing it at such a high rate that we cannot recycle the problem away. Plastic production increased exponentially, from 2.3 million tons in 1950 to 448 million tons by 2015, and it is expected to double by 2050.9 “Plastic is too microscopically dispersed around the world to try and clean it all up at this point…Prevention and avoidance should be engraved in our minds,” wrote Chantal Plamondon and Jay Sinha in Life Without Plastic.10 Companies and manufacturers must stop producing so much of it!

“Half of all plastics ever manufactured have been made in the last 15 years.”11

Watch this short film about plastic from The Story of Stuff Project:

“We have polluted the planet with indestructible plastic to such a degree that plastic may serve as a fossil marker in our strata to indicate a new era – the way dinosaurs indicate the Mesozoic one – until Big Oil digs the last of those reptiles up to produce more Coke bottles.” -Anne-Marie Bonneau, author of The Zero-Waste Chef12

What To Do

Whatever it takes to slow or stop the neverending barrage of chemical toxicity and plastic pollution being perpetrated on our planet by profit-driven entities, you can start at home and start small. You can avoid and refuse single-use plastic, changing your habits surrounding it one step at a time. I offer many ways to eliminate plastic on my site in my articles such as “11 Ways To Go Plastic-Free With Food,” and under Resources, where there are lists of books, films, and other websites that offer good information.

You have to eliminate plastics in your life in small manageable chunks, because there’s just so much of it. As the founders of Life Without Plastic wrote, “As excited as you may be to embark on this journey, be careful about fully embracing plastic-free living cold turkey, and trying to do it all at once. Once you start noticing the plastic around you, it could overwhelm and discourage you quickly…Take it one step at a time. This is all about changing habits, and that takes time, effort and patience.”13 This will protect you and your family from potentially toxic products entering your body and harming your health.

Contact companies whose products you consume and ask them to switch to responsible packaging. Switch the products you use with items that don’t have plastic. Support legislation like the Break Free From Plastic Pollution Act.14 Getting manufacturers and companies to stop the overproduction of plastics will be key, and to do so we will have to force them through purchase power and legislation.

“We are surrounded by the toxic polluting conundrum that versatile convenient plastic has become. But . . . there are lots of ways to avoid plastics in everyday life – wherever you are, whatever you do. All it takes is a little awareness and initiative. Educated actions, we like to call it.” –Chantal Plamondon and Jay Sinha, Life Without Plastic15

Thank you for reading, and please share and subscribe!

 

Additional Resources:

Video, “Plastics 101,” National Geographic, May 18, 2018.

Guide to My Packaging Industry Series.

Footnotes: