The number inside the recycling symbol on plastic bottles identifies the type of resin used in manufacturing. This six-digit code, known as the Resin Identification Code (RIC), determines material composition, recyclability, and environmental impact. The number ranges from 1 to 7 and appears within a triangle formed by three arrows.
These codes were developed by the Society of the Plastics Industry in 1988 to standardize plastic identification globally. They appear on most rigid plastic packaging, including bottles, containers, and food trays. The system helps municipalities sort plastics efficiently and informs consumers about proper disposal methods.
Not all numbers indicate recyclable materials. Some, like #3 (PVC) and #7 (other), often end up in landfills due to contamination risks and limited processing infrastructure. Understanding the number allows individuals to make informed choices about product use and disposal.
Each number corresponds to a specific polymer type. The code is embedded in the plastic during molding and cannot be altered without remanufacturing. The number appears inside a triangle formed by three arrows pointing clockwise, symbolizing the recycling loop.
For example, a water bottle labeled #1 contains polyethylene terephthalate (PET). This material is lightweight, clear, and widely recycled into new bottles and fibers for textiles. A milk jug marked #2 is high-density polyethylene (HDPE), which resists chemicals and is commonly recycled into outdoor furniture and plastic lumber.
Numbers 3 through 7 represent less common or more complex polymers. #3 is polyvinyl chloride (PVC), used in pipes and cling film. It poses health risks during incineration and is rarely recycled. #7 includes all other plastics, such as polycarbonate and bioplastics, many of which are not accepted in curbside programs.
Here's a breakdown of the seven resin codes and their typical applications:
| Number | Resin Type | Common Products | Recyclability |
|---|---|---|---|
| 1 | PET (Polyethylene Terephthalate) | Water bottles, soda bottles | High - widely accepted |
| 2 | HDPE (High-Density Polyethylene) | Milk jugs, detergent bottles | High - commonly recycled |
| 3 | PVC (Polyvinyl Chloride) | Plumbing pipes, shrink wrap | Low - toxic when burned |
| 4 | LDPE (Low-Density Polyethylene) | Plastic bags, produce bags | Medium - varies by location |
| 5 | PP (Polypropylene) | Yogurt containers, medicine bottles | Medium - growing acceptance |
| 6 | PS (Polystyrene) | Styrofoam cups, takeout containers | Low - often banned |
| 7 | Other (including bioplastics) | Food storage containers, electronics casings | Variable - many not recyclable |
When I sorted household waste during a community cleanup in Portland, I noticed that #4 LDPE bags were frequently mixed with paper waste. These bags often clog sorting machinery and require manual removal. Local recycling centers now accept them only at designated drop-off points.
Many people assume that any number inside the recycling symbol means the item is recyclable. That's false. The number only identifies the plastic type-not whether a facility can process it. For example, #7 includes both recyclable bioplastics and non-recyclable polycarbonates.
Another mistake is assuming that clear plastic means recyclable. A #1 PET bottle may be transparent, but a #3 PVC container can look identical. Only the number reveals the actual material. Without the code, visual inspection fails.
A lesser-known fact: the number doesn't indicate how many times a plastic can be recycled. PET (#1) can be recycled into new bottles up to 10 times, but each cycle degrades molecular structure. After several cycles, the material becomes too weak for reuse and ends up in landfills.
Proper identification reduces contamination in recycling streams. Contaminated batches often get sent to landfills. According to the Environmental Protection Agency, nearly 30% of recyclables are rejected due to improper sorting. Knowing the number helps prevent this.
Consumers who choose products with #1 or #2 codes support systems with higher recovery rates. In 2022, the U.S. recycled 32% of PET bottles and 30% of HDPE containers, according to the National Association for PET Container Resources. These figures rise when people correctly identify and separate materials.
When shopping, look for bottles labeled #1 or #2. Avoid those with #3, #6, or #7 unless they're certified compostable or collected through specialized programs. If unsure, check local guidelines-some cities accept #4 LDPE bags at grocery store bins.