Expanded Polystyrene (EPS)

In short

Expanded polystyrene is roughly 98% air and 2% plastic, which is exactly what makes it so difficult. It is not accepted in kerbside recycling anywhere in New Zealand, because it shatters into beads that contaminate everything around them. Clean, large blocks can sometimes be taken to a specialist drop-off; food-contaminated foam and packing chips realistically go in the rubbish.

What it's made of

What something is made from is what decides where it can go — this is usually the reason an item can't be recycled.

• Polystyrene, plastic resin code 6, expanded with air into beads and fused into a block.
• Between 95% and 98% of the finished volume is air, which is why it weighs so little and takes up so much space.
• Meat trays and takeaway containers are the same plastic, usually with food residue that rules out recycling.

Before you get rid of it

1. Keep it clean and dry. Contaminated foam has no recycling route at all.
2. Keep whole blocks whole. Snapping them up creates beads, which blow away and are almost impossible to collect.
3. Separate food-contaminated foam from clean packaging foam — they have different answers.
4. If you are looking for a drop-off, ring first. The facilities that densify EPS are limited and not every site takes it from the public.

Common mistakes

• Putting it in the kerbside recycling bin. It breaks into beads on the truck, and those beads spread through the whole load and contaminate the genuinely recyclable material.
• Confusing it with soft plastics. Soft plastic bags and wrap have their own in-store collections; rigid foam does not belong in those bins.
• Assuming all white foam is polystyrene. Some packaging foam is polyethylene or polypropylene, which feels rubbery and flexible rather than squeaky and brittle.
• Using loose beads as garden drainage material. They escape into soil and waterways and are effectively impossible to recover.

Better than binning it

• Clean blocks are worth keeping if you post things — EPS is excellent packing material and reusing it is better than any recycling route.
• Packing and moving companies will sometimes take clean blocks and chips off your hands.
• Large sheets have real insulation value and are used in building and in projects like cool boxes and seed propagators.
• Ask suppliers who deliver in EPS whether they take their packaging back — some do, particularly for appliances and whiteware.

What happens to it

EPS can be recycled, and the technology is straightforward: a densifier compresses the foam and drives the air out, turning a bulky block into a dense ingot of polystyrene that can be remade into products like picture frames and insulation. The obstacle is economics rather than chemistry. Transporting something that is 98% air is expensive, so collection points are scarce and tend to exist only where a densifier is nearby.

Questions people ask