Many, but not all, plastic products have a number – the resin identification code – molded, formed or imprinted in or on the container, often on the bottom. This system of coding was developed in 1988 by the U.S.-based Society of the Plastics Industry to facilitate the recycling of post-consumer plastics. It is indeed, quite interesting to go through the fine lines.
1. Polyethylene terephthalate (PET or PETE)
Polyethylene terephthalate (PET or PETE) is one of the most common types of plastic and is commonly found in bottles of soda, juice, water and cough syrup and jars of peanut butter. The bottoms of these containers are usually stamped with the chasing arrows symbol and the number 1, the code for PET.
2. High-density polyethylene (HDPE)
High-density polyethylene (HDPE) – Used in opaque milk, water, and juice containers, bleach, detergent and shampoo bottles, garbage bags, yogurt and margarine tubs, and cereal box liners. Considered a safer plastic. Research on risks associated with this type of plastic is ongoing.
3. Polyvinyl chloride (V or Vinyl or PVC)
Polyvinyl chloride (V or Vinyl or PVC) Used in toys, clear food and non-food packaging (e.g., cling wrap), some squeeze bottles, shampoo bottles, cooking oil and peanut butter jars, detergent and window cleaner bottles, shower curtains, medical tubing, and numerous construction products (e.g., pipes, siding). PVC has been described as one of the most hazardous consumer products ever created. Leaches di (2-ethylhexyl) phthalate (DEHP) or butyl benzyl phthalate (BBzP), depending on which is used as the plasticizer or softener (usually DEHP). DEHP and BBzP are endocrine disruptors mimicking the female hormone estrogen; have been strongly linked to asthma and allergic symptoms in children; may cause certain types of cancer; and linked to negative effects on the liver, kidney, spleen, bone formation, and body weight. In Europe, DEHP, BBzP, and other dangerous phthalates have been banned from use in plastic toys for children under three since 1999. Not so elsewhere, including Canada and the United States. Dioxins are unintentionally, but unavoidably, produced during the manufacture of materials containing chlorine, including PVC and other chlorinated plastic feedstocks. Dioxin is a known human carcinogen and the most potent synthetic carcinogen ever tested in laboratory animals. A characterization by the National Institute of Standards and Technology of cancer causing potential evaluated dioxin as over 10,000 times more potent than the next highest chemical (diethanol amine), half a million times more than arsenic, and a million or more times greater than all others.
4. Low-density polyethylene (LDPE)
Low-density polyethylene (LDPE) – Used in grocery store, dry cleaning, bread and frozen food bags, most plastic wraps, and squeezable bottles (honey, mustard). Considered a safer plastic. Research on risks associated with this type of plastic is ongoing.
5. Polypropylene (PP)
6. Polystyrene (PS)
Polystyrene (PS) – Used in Styrofoam containers, egg cartons, disposable cups and bowls, take-out food containers, plastic cutlery, and compact disc cases. Leaches styrene, an endocrine disruptor mimicking the female hormone estrogen, and thus has the potential to cause reproductive and developmental problems. Long-term exposure by workers has shown brain and nervous system effects and adverse effects on red blood cells, liver, kidneys, and stomach in animal studies. Also present in secondhand cigarette smoke, off gassing of building materials, car exhaust, and possibly drinking water. Styrene migrates significantly from polystyrene containers into the container’s contents when oily foods are heated in such containers.
This is a catchall category that includes anything that does not come within the other six categories. As such, one must be careful in interpreting this category because it includes polycarbonate – a dangerous plastic – but it also includes the new, safer, biodegradable bio-based plastics made from renewable resources such as corn and potato starch and sugar cane. Polycarbonate is used in many plastic baby bottles, clear plastic sippy cups, sports water bottles, three and five gallon large water storage containers, metal food can liners, some juice and ketchup containers, compact discs, cell phones, computers. Polycarbonate leaches Bisphenol A (some effects described above) and numerous studies have indicated a wide array of possible adverse effects from low-level exposure to Bisphenol A: chromosome damage in female ovaries, decreased sperm production in males, early onset of puberty, various behavioral changes, altered immune function, and sex reversal in frogs.