Seven groups of plastic polymers,each with specific properties, are used worldwide for packaging applications (see table below). Each group of plastic polymer can be identified by its Plastic Identification code (PIC) - usually a number or a letter abbreviation. For instance, Low-Density Polyethylene can be identified by the number 4 and/or the letters "LDPE". The PIC appears inside a three-chasing arrow recycling symbol. The symbol is used to indicate whether the plastic can be recycled into new products. The PIC was introduced by the Society of the Plastics Industry, Inc. which provides a uniform system for the identification of different polymer types and helps recycling companies to separate different plastics for reprocessing. Manufacturers of plastic products are required to use PIC labels in some countries/regions[16] and can voluntarily mark their products with the PIC where there are no requirements. Consumers can identify the plastic types based on the codes usually found at the base or at the side of the plastic products, including food/chemical packaging and containers. The PIC is usually not present on packaging films, as it is not practical to collect and recycle most of this type of waste.

The quantity of post-consumer plastics recycled has increased every year since at least 1990. In 2006 the amount of plastic bottles recycled reacheda record high of 2,220,000,000 pounds. The amount of PET bottles recycled in 2006 increased more than 102 million pounds compared to 2005. HDPE bottle recycling increased in 2005 to 928 million pounds. All plastic bottles were recycled at a rate of 24 percent in 2005. In regard to plastic identification codes 3 and 7, the matter of biological risks posed by Bisphenol A monomer leaching from plastic products such as beverage bottles is the subject of expanding controversy.