Styrene

Styrene is an unsaturated liquid hydrocarbon, a by-product of petroleum manufacture, polymerized to make polystyrene resins and plastics used as packaging materials for foods such as yoghurt cups, trays, and foam containers. Health concerns surround the migration of styrene monomers, dimers, and trimers from packaging into certain foods — especially fatty foods and those held at elevated temperatures. Regulators set specific migration limits, and manufacturers test packaging under worst-case conditions. Choosing appropriate packaging materials and respecting use conditions keeps migration within safe bounds.