Plastics are simply chains of like molecules linked together. They are derived from precursor materials including hydrocarbons such as coal, natural gas, and crude oil. Increasingly plastics are made from organic, sometimes even compostable, matter such as cellulose and soil. While some may remember when plastic was a synonym for “inferior,” now it is ubiquitously used, and many industries are dependent on it.

The term “plastic” is derived from the Greek word “plastikos,” meaning fit for molding. This aptly describes the material’s malleability (plasticity if you will), which allows it to be pressed, cast, or extruded into films, fibers, tubes, boxes, bottles and more. Plastics have numerous useful properties, including strength, durability, low weight, disposability, low-cost, resistance to microorganism growth, opacity, translucence, and ease of molding and manufacture. In healthcare, for example, plastic can make products safe and sterile while still being inexpensive and easily disposed.

The most common types of plastics are:

Polyethylene Terephthalate (PET): Frequently used for food and drink containers because of its ability to keep oxygen out, as well as in fibers for clothing.

High Density Polyethylene (HDPE): A strong and stable plastic used in a variety of applications including plastic bottles, cutting boards and piping.

Polyvinyl Chloride (PVC or Vinyl): Considered the most toxic plastic, PVC is used in items such as toys, cling wrap and medical tubing.

Low Density Polyethylene (LDPE): Due to its thinner and more flexible nature than other plastics, LDPE is used in grocery bags, laundry bags, and coatings for milk containers and wire and cables.

Polypropylene (PP): Stiff and resistant to heat, PP is most frequently used in hot food containers.

Polystyrene (PS or Styrofoam) Commonly used in medical device applications like test tubes or petri dishes, in day-to-day items such as the housing on smoke detectors, and frequently as containers for foods like yogurt or disposable drinking cups.

All other plastics are known as “Number 7” plastics, including plastics that are mixed or layered with other plastics.
For all its benefits, plastics have been under scrutiny because of growing concerns over waste, high carbon footprint, and unnecessary resource use. Emerging research also suggests that microplastics, plastic pieces smaller than 5 millimeters, are increasingly prevalent in the natural world, including in the ocean, drinking water, and even within seafood, meat, fruits and vegetables.

Recent lawsuits allege a variety of harm from plastics. An environmental public interest group sued the U.S. Environmental Protection Agency in August 2021 for failing to regulate PVC as hazardous waste. PVC is one of the most widely used and discarded forms of plastic, yet numerous studies have found it’s highly toxic to human health and the environment and sheds carcinogens throughout its life cycle.

Other lawsuits allege that plastics manufacturers cause public harm through failure to disclose the environmental and health risks of plastics. These types of cases typically allege nuisance and other tort causes of action, including negligence and strict products liability.