Polystyrene (PS)

What it is

Polystyrene carries the number 6 in the recycling triangle. It comes in two very different forms:

• Foamed polystyrene (expanded, EPS, or extruded, XPS), the light white foam of takeaway boxes, cups and protective packaging. It's often called Styrofoam, which is strictly a brand of insulation foam.
• Solid polystyrene, a hard, brittle, often clear plastic used for some yoghurt pots, disposable cups and cutlery.

The England ban

Since 1 October 2023 businesses in England can't supply food or drink that's ready to eat in expanded or extruded polystyrene containers, including foam cups. The ban covers online and over-the-counter sales. Polystyrene boxes used to move unprepared food through the supply chain, such as fish boxes, are exempt. Scotland and Wales have their own similar rules.

What about styrene?

Polystyrene is made from styrene. The International Agency for Research on Cancer classes styrene as probably carcinogenic to humans (Group 2A), based mainly on evidence from workers exposed in industry and from animal studies.

That classification describes how strong the evidence is that a substance can cause cancer, not how much risk a given exposure carries. It doesn't mean a foam cup is as risky as factory exposure. But heat and fat make it easier for residual styrene to move into food and drink, so it's sensible to keep polystyrene away from both.

How to avoid it

• Bring your own cup and container for takeaways: takeaway cups → reusable.
• Don't microwave food in polystyrene trays or pots.
• Buy meat and fish from a counter into your own container where you can.

Recycling

WRAP lists polystyrene as not recyclable in UK packaging, and any PS component can make a whole pack unrecyclable. Put it in general waste. Some council tips have separate collections for clean white packaging foam, so check before a big delivery.