Plastic Labelling - What do Those Numbers Mean?

So what is that little number in a triangle on the bottom of your plastic bottle, anyway? What does it mean, and what's it good for?

Those numbers represent a system of codes developed by the Society of the Plastics Industry (SPI) in 1988 to identify the type of plastic in the product. The coding is voluntary, and largely unregulated, meaning we have to rely on the honesty and integrity of the manufacturers in their use of the codes.

There are seven codes based on the varying resin contents of the plastics (the seventh is a catch all 'other'). Unfortunately, the presence of the code does not mean that the product can be recycled in any given community. In Saskatchewan, most of the plastics recycled are beverage containers, consisting largely of #1's and #2's.

The following chart is adapted from the American Plastics Council and outlines the seven codes, a description of each type, its packaging applications, and recycled products made from it.

Polyethylene Terephthalate (PET or PETE)	PET is clear, tough and has good gas and moisture barrier properties. This plastic is commonly used in PET soft drink bottles and many other injection molded consumer product containers. Cleaned recycled PET flakes and pellets are in great demand for spinning fiber for carpet yarns and producing fiberfill and geotextiles. Polyester is its nickname. PET bottles are intended for single use, as PET breaks down with use and cannot be properly cleaned. The concern with PET products is not toxins, but the buildup of bacteria due to infrequent or insufficient cleaning. Scratches and imperfections in the plastic may host germs.
	Packaging Applications: Plastic soft drink and water bottles, beer bottles, mouthwash bottles, peanut butter and salad dressing containers, ovenable food trays.	Recycled Products: Fiber tote bags, bottles, clothing (such as Polar Fleece), furniture, carpet, panelling, straps, new containers.. Most programs that accept plastics accept PET.
High Density Polyethylene (HDPE)	Unpigmented, HDPE bottles are translucent and have good barrier properties and stiffness. They are well suited to packaging products with short shelf lives such as milk, margarine tubs and yogurt containers. Because HDPE has good chemical resistance, it is used for packaging many household as well as industrial chemicals such as detergents and bleach. Pigmented HDPE bottles generally have better stress crack and chemical resistance than bottles made from unpigmented HDPE. It carries a low risk of leaching, and is readily recyclable.
	Packaging Applications: Milk, water and juice containers, trash and retail bags, liquid detergent bottles, yogurt and margarine tubs, cereal box liners.	Recycled Products: Liquid laundry detergent containers, drainage pipe, oil bottles, recycling bins, benches, pens, doghouses, floor tile, picnic tables, lumber, mailbox posts, fencing. Most programs that accept plastics accept HDPE.
Vinyl (Polyvinyl Chloride or PVC)	In addition to its stable physical properties, PVC has excellent chemical resistance, good weatherability, flow characteristics and stable electrical properties. Bottles and packaging sheet are major markets, but it is also widely used in the construction market for such applications as pipes and fittings, insulation, film and sheet, floor coverings, synthetic leather products, coatings, blood bags, medical tubing and many other applications. It contains chlorine, so its manufacture can release highly dangerous dioxins. Number 3 has been nicknamed the "toxic plastic" due to the softeners (DEHA) that with long-term exposure may cause cancer and other health issues.
	Packaging Applications: Clear food packaging, shampoo bottles, medical tubing, wire and cable insulation, siding, windows, pipes.	Recycled Products: Packaging, binders, decking, panelling, roadway gutters, mud flaps, film and sheet, flooring, cables, speed bumps, mats. Rarely recycled; accepted by some plastic programs.
Low density Polyethylene (LDPE)	A plastic used predominately in film applications due to its toughness, flexibility and relative transparency, making it popular for use in applications where heat sealing is necessary. LDPE is also used to manufacture some flexible lids and bottles and it is widely used in wire and cable applications for its properties and processing characteristics. It does not transmit any known chemicals into food.
	Packaging Applications: Bread bags, frozen food bags, squeezable bottles (e.g. honey, mustard), fibre, tote bags, bottles, clothing, furniture, carpet.	Recycled Products: Shipping envelopes, garbage can liners, floor tile, furniture, film and sheet, compost bins, panelling, trash cans, lumber. Accepted by some communities' programs; plastic shopping bags can be returned to many stores for recycling.
Polypropylene (PP)	Polypropylene has excellent chemical resistance, is strong, and has the lowest density of the plastics used in packaging. It has a high melting point, making it ideal for hot fill liquids. PP is found in everything from flexible and rigid packaging to fibers and large molded parts for automotive and consumer products. It is a safe, toxin-free alternative for food and beverage containers.
	Packaging Applications: Ketchup bottles, yogurt containers and margarine tubs, medicine bottles, straws, caps.	Recycled Products: Auto battery cases, brooms and brushes, oil funnels, landscape borders, bicycle racks, bins, pallets, sheeting, rakes. Accepted by some programs.
Polystyrene (PS)	Polystyrene is a very versatile plastic that can be rigid or foamed. General purpose polystyrene is clear, hard and brittle. It has a relatively low melting point. Typical applications include protective packaging, containers, lids, cups, bottles and trays. Evidence suggests polystyrene can leach potential toxins into foods.
	Packaging Applications: Compact disc jackets, food service applications, grocery store meat trays, egg cartons, aspirin bottles, disposable cups & plates.	Recycled Products: Thermal insulation, egg cartons, vents, desk trays, rulers, license plate frames, foam packaging, carryout containers. Clear PS is sometimes accepted by recycling programs; "Styrofoam" is rarely recycled.
Other	Use of this code indicates that the package in question is made with a resin other than the six listed above, or is made of more than one resin used in combination. A few are made from plants (polylactide) and are compostable under the right conditions. Polycarbonate is No. 7, and is the hard plastic that has parents worried these days, after studies have shown it can leach potential hormone disruptors.
	Packaging Applications: Three and five gallon reusable water bottles, some citrus juice and ketchup bottles, 'bullet-proof' materials, DVDs, sunglasses, iPod and computer cases, signs and displays, certain food containers, Nylon.	Recycled Products: Custom products, plastic lumber. Accepted by some programs.

(Source: WasteWatch, September 2002; updated August, 2008)

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