Standards for Plastic Recycling Symbols

Recycling plastic saves resources and energy. Plastic manufacturers have standard codes for plastic resins to help recyclers sort plastic. The code number is usually printed within the triangular chasing-arrows symbol on the plastic. The numerals for one through six represent specific resins, while a "7" represents any other plastic types.

Resin 1

• Polyethyene terephthalate, abbreviated as PET or PETE, is labeled with a "1." This category of plastic is commonly used in food packaging and drink bottles.

Resin 2

• Plastic labeled with a "2" is high-density polyethylene, or HDPE. The plastic is used for products with a short shelf life, like milk, but its chemical resistance makes it useful for laundry detergent and motor oil containers.

Resin 3

• Polyvinyl chloride, or PVC, is coded with a "3." Rigid PVC is used for clamshell packaging, while flexible PVC is used in shrink wrap and linings for milk cartons.

Resin 4

• Low-density polyethylene, or LDPE, is coded with a "4." This plastic is used mostly as a film in bags, like dry cleaning or shopping bags, or in lids for containers.

Resin 5

• Resin No. 5 is polypropylene, or PP. It tends to be used as a rigid plastic and has a high melting point, allowing it to hold hot injected material. Pill bottles, margarine tubs and milk jug caps are commonly made from the material.

Resin 6

• Resin No. 6 is polystyrene, or PS. It's commonly used as a packaging foam in food service applications.