Resin Identification Codes: A Comprehensive Guide to Plastic Recycling

What Are the Resin Identification Codes from SPI?

The Resin Identification Code (RIC) system was launched by the Society of the Plastics Industry (SPI) in 1988, which is now known as The Plastics Industry Association. The RIC assigns a single digit (1‑7) inside a triangle of three bending arrows to each type of plastic. While no federal law mandates its use, many state and local recycling programs require it, making the symbol essential for sorting plastics at recycling facilities.

Only codes 1, 2, 4, and 5 are accepted by most municipalities, whereas 3, 6, and 7 are generally not recyclable. The following sections explain each code and its common applications.

1 – PET (Polyethylene Terephthalate)

Commonly labeled as PET or PETE, this lightweight, clear plastic was once called Dacron. It is the material of choice for most single‑serve and 2‑liter soda and water bottles in the United States. PET is also used for packaging salad dressings, cooking oils, window cleaners, shampoos, mouthwash, liquid hand soap, and peanut butter.

2 – HDPE (High‑Density Polyethylene)

HDPE is a versatile thermoplastic derived from petroleum. It is prized for its high impact resistance and elevated melting point. Common household items made from HDPE include colored detergent bottles, milk jugs, shampoo bottles, bleach containers, cutting boards, and many plumbing pipes.

3 – PVC (Polyvinyl Chloride)

PVC, also known as vinyl, is one of the world’s most widely used plastics, second only to polyethylene and polypropylene. Although it appears in a range of products—from door and window profiles to water‑pipe systems, medical tubing, and bottle caps—PVC is not recyclable under most municipal programs.

4 – LDPE (Low‑Density Polyethylene)

LDPE is a flexible, clear or translucent plastic that resists chemicals and water. It is commonly found in dry‑cleaning bags, produce bags, garbage bags, plastic wrap, and various injection‑molded parts. Unfortunately, LDPE is rarely accepted by recycling facilities.

5 – PP (Polypropylene)

Polypropylene has a higher melting point, making it suitable for containers that hold hot liquids. Although recycling acceptance is increasing, PP remains less common in municipal streams. Typical PP products include potato‑chip bags, cereal‑box liners, sour‑cream and yogurt containers, margarine tubs, bottle caps, carpets, syrup bottles, and medicine vials.

6 – PS (Polystyrene)

Polystyrene is the material used in disposable coffee cups and many foam food containers. It is not generally recyclable and represents roughly 35 % of landfill plastic waste.

7 – Miscellaneous (Other Resins)

Code 7 covers a variety of plastics that cannot be classified under the other six categories, such as nylon, polycarbonate, acrylic, multi‑layer composites, and the newer corn‑derived PLA (polylactic acid). Because the recyclability of these materials varies widely, items marked with a “7” should not be placed in the general recycling bin.

How to Find the Code on a Product

The RIC may be molded directly into the plastic or printed on the product label. Before depositing an item into the recycling bin, check for the triangular symbol and confirm that the number inside is 1, 2, 4, or 5. Items with codes 3, 6, or 7 should be discarded or sent to a specialized recycling facility if available.

Remember, the RIC is not a federal requirement, but it provides essential information for recycling personnel. Without the code, a plastic item may be misidentified and end up in the trash.