Have you ever wondered about those little numbers with the arrows around them, on the bottom of plastic containers? They’re called resin identification codes, and they indicate the type of plastic that an item is made from. These numbers are intended to help consumers know whether and how to recycle various plastic products and packages.

In 1988 the plastics industry, through the Society of the Plastics Industry, Inc., introduced its voluntary resin identification coding system. A growing number of communities were implementing recycling programs in an effort to decrease the volume of waste subject to rising tipping fees at landfills. In some cases, test programs were driven by state-level recycling mandates.The code system was developed to meet recyclers’ needs while providing manufacturers a consistent, uniform system that could apply nationwide. Because municipal recycling programs traditionally have targeted packaging – primarily bottles and containers – the resin coding system offered a means of identifying the resin content of bottles and containers commonly found in the residential waste stream. #1 plastics are made of PET (PolyEthylene Terephthalate). Most soda and water bottles bottles, like the Ice Mountain bottle above, are PET plastic. These bottles are lightweight, shatter-resistant, and easily recycled. They are considered disposable, and therein lies the problem.#2 plastics consist of HDPE (High Density PolyEthylene.) Detergent bottles and milk jugs are made of HDPE. They are inexpensive, sturdy, and can also be recycled readily. You can buy reusable water bottles made of HDPE, and, as it turns out, I have one.#3 through #6 plastics are used in dry cleaning bags and drinking straws, Styrofoam packing peanuts and produce bags, plastic food wraps and pill vials, CD cases and a million other things in our plasticized world. While recyclable in theory, practically speaking it is hard to find anyone to take these off your hands.And then, there is category #7: “Other.” This catch-all label includes reusable food containers, Tupperware, and reusable water bottles. Nalgene <http://www.nalgenechoice.com/?gclid=COam-pDHhpQCFQsiIgodGEpwWg>  is a popular brand name water bottle made of #7 plastic. Environmentally aware consumers have being toting their Nalgene water bottles around for quite a while, but reports linking the compound BPA (BisPhenol A) found in this type of plastic to various health risks have put a bit of a damper on their enthusiasm.