What Do the Recycling Numbers on Plastic Mean?

The numbers are resin identification codes. The FTC Green Guides say the resin identification code, formerly known as the Society of the Plastics Industry code, is now covered by the standard ASTM D 7611. The NIH Office of Research Facilities lists the codes as 1 for polyethylene terephthalate (PET), used in soda bottles, cooking oil bottles and peanut butter jars, 2 for high density polyethylene (HDPE), used in milk jugs, detergent bottles and grocery bags, 3 for polyvinyl chloride (PVC), used in blister packs, clamshells and shrink wrap, 4 for low density polyethylene (LDPE), used in bread and frozen food bags, trash can liners and squeezable bottles, 5 for polypropylene (PP), used in straws, medicine bottles and yogurt and take-out containers, 6 for polystyrene (PS), used in packing peanuts, cups and meat trays, and 7 for other or mixed grade plastics.

The code alone does not mean an item is recyclable. The FTC Green Guides say a conspicuous resin code on a container counts as a recyclable claim, and that unless recycling facilities for the container are available to a substantial majority of consumers or communities, the manufacturer should qualify the claim, while a code placed inconspicuously, such as embedded in the bottom of the container, is not a recyclable claim. The EPA says about three million tons of plastics were recycled in 2018, an 8.7% recycling rate, while PET bottles and jars were recycled at 29.1% and natural HDPE bottles at 29.3%.

California has added its own rule. Its SB 343, approved by the Governor on October 5, 2021, prohibits placing the resin identification code inside a chasing arrows symbol unless the rigid plastic bottle or container meets the state requirements for statewide recyclability. CalRecycle says the labeling restrictions apply to products and packaging manufactured after October 4, 2026, and that on July 14, 2026, a federal court in California League of Food Producers v. Bonta issued a preliminary injunction that blocks enforcement of SB 343.