Plastic production began when the technology emerged at the beginning of the 20th century, with mass production taking off around 1950. Production requires fossil fuels, i.e., oil and gas, which are limited resources. Crude oil is pumped up from underground and processed in oil refinery facilities. During the refining process reactive monomers are created. These monomers are collected and bonded through the introduction of a catalyst. This process creates long-chain molecules called polymers. These polymers accumulate to form a malleable mass that can easily be shaped. Various combinations of polymers (i.e., how the polymers are ordered) yield different types of plastics. During production certain additives (e.g., chloroethane or BPA) are used to modify the characteristics of the plastic like to strengthen it.
Different production methods transform crude oil into various types of plastic.
Plastic is typically classified into seven types. Plastic packaging often bears the recycling triangle symbol around a number, which corresponds to the plastic type.
Seven Types of Plastic
♳ PETE (#1) is PET plastic and is a valuable plastic that lends itself to recycling. Used to make soda bottles.
♴ HDPE (#2) is high-density polyethylene, which is one of the most common plastics. Used in containers for personal hygiene products. Also lends itself to recycling.
♵ PVC (#3) is PVC plastic, or polyvinyl chloride, is used in rainproof clothing, rain boots, shower curtains, toys, oilcloth, electrical wiring, plumbing pipes, etc. PVC plastic can release harmful substances, like phthalates, heavy metals (lead, mercury, cadmium) and dioxin, which can leach out into the environment.
♶ PE-LD (#4) is low-density polyethylene and is used to make items like plastic bags. Also well suited for recycling.
♷ PP (#5) or polypropylene is used as a packaging for food items (ketchup bottles, yogurt cups, etc.) and is well suited for recycling.
♸ PS (#6) is polystyrene or styrofoam and is often used for food containers like styrofoam clamshell containers.
♹ Other (#7) is the catchall category for other types of plastic. This includes ABS plastics like those found in LEGO blocks and bioplastics marked PLA.
Controversial Substances in Plastic
BPA or bisphenol A is an organic compound used in the production of various plastics. It is found as a preservative in fabric softeners and a structural component in polycarbonate plastics and epoxy resins, the latter of which is used as a liner in canned food and drinks. BPA is also found in water bottles, baby bottles and snack boxes.
It has been shown that BPA can leach out of plastic and into liquids, the risk increasing with prolonged use and when the plastic is heated the effect is multiplied. The same applies when hot liquids are poured into the plastic container.
In the human body BPA mimics the hormone estrogen, which can interfere with normal endocrine functions. BPA has been shown to impede normal development of the brain and nervous system and also cause infertility and developmental abnormalities.
Phtalates are a group of chemicals used to make plastics more pliable and flexible. Several types of phtalates can interrupt normal hormone activity in the human body and have a detrimental effect on fertility. Fetuses and newborns are especially susceptible to these chemicals, which is troublesome as phtalates have been found in breastmilk. The EU has put into place regulations that ban the use of certain phtalates in toys. To safeguard against phtalate toxicity, PVC plastics should always be taken to recycling centers for disposal.