What plastic is marked 6?

What Does the Number 6 on Plastic Mean?

Ever flipped over a plastic container or toy and seen a tiny number inside a recycling symbol? If it’s a 6, you’re looking at polystyrene, also known as PS—short for polystyrene. This type of plastic is widely used across everyday products, from rigid packaging to disposable drink cups.

Polystyrene comes in two main forms: rigid and foamed (commonly known by the brand name Styrofoam, though that’s technically a trademarked product). The rigid version, marked with the number 6, shows up in items like CD cases, cosmetic organizers, hard plastic toys, and even some refrigerator trays. It’s valued for being lightweight, clear, and relatively inexpensive to produce.

However, despite its widespread use, polystyrene has a problematic side. It’s notoriously difficult to recycle, and many municipal recycling programs don’t accept it. When discarded, it often ends up in landfills or polluting the environment, where it can take hundreds of years to break down. Moreover, when burned or exposed to heat, polystyrene can release harmful chemicals, raising health and environmental concerns.

You’ll also find PS in costume jewelry and vending cups—items designed for short-term use but with long-term consequences. As awareness grows, more people are pushing for alternatives, especially in food packaging where hot liquids can cause styrene to leach into drinks.

So next time you see that little "6" inside the recycling triangle, remember: it’s polystyrene—versatile but problematic. Choosing reusable or more easily recyclable materials when possible is a small step with a bigger impact.