Are Styrofoam coffee cups safe for hot drinks?

What's in a Styrofoam cup

Styrofoam cups (expanded polystyrene) are used at gas stations, offices, and diners across the country. The material is made from styrene, a chemical classified as a possible human carcinogen. When you pour hot coffee or tea into one of these cups, the heat softens the material and accelerates the release of styrene and other compounds into your drink.

Unlike thicker plastic cups, Styrofoam is especially porous and lightweight, which means chemicals escape more easily when exposed to heat.

What the research says

A 2026 study tested chemical migration from polystyrene and other disposable cups into hot beverages. The results showed that styrene, phthalates, and other plastic additives migrated into the liquid, with higher temperatures causing faster and greater release.

The study found that a single hot drink in a Styrofoam cup can expose you to measurable levels of these chemicals. For someone who drinks multiple cups of coffee per day from these containers, the daily exposure adds up quickly.

Safer alternatives

Bring your own ceramic or stainless steel travel mug. If you're stuck with disposable options, uncoated paper cups are a step up from Styrofoam, though they still have a thin liner. Avoid letting hot drinks sit in Styrofoam for extended periods. The longer the contact time, the more chemicals your drink absorbs.