Polystyrene

A synthetic resin from polymerized styrene, made in two forms: a hard, clear one used for yogurt pots, meat trays, and disposable cups, and a light foam version known as expanded polystyrene for takeaway boxes, cups, and protective trays. Health concerns center on styrene monomers, dimers, and trimers migrating from the packaging into some foods, particularly hot or fatty ones. Expanded foam insulates well but is bulky to recycle, driving shifts toward alternative food-service packaging. Food-contact grades must meet migration limits, and manufacturers test them under realistic use conditions.