Expanded Polystyrene is a safe and highly resource-efficient material
Put simply, EPS is 98% air and 2% plastic. It uses, as its base material, a polymer called styrene monomer. The monomer is a by-product of petroleum and naphtha produced during oil refining which provides a ready and continuous source. Styrene also occurs naturally in many foods such as strawberries, coffee beans, beer and wine.
A gas called pentane is used as a non-CFC expansion agent to blow the styrene into its final lightweight, expanded cellular form. During the production process, the styrene monomer is effectively eliminated during its polymerisation and the pentane is quickly broken down into carbon dioxide and water. Pentane has low volatility – for example, it is found in the digestive systems of animals and created when vegetable matter decomposes in a process called anaerobic composting.
On the basis of current EU testing and classification regimes, styrene monomer is non-toxic in all normal usage and is not classified in terms of carcinogenicity or mutagenicity. Pentane has no potential to harm the ozone layer with CFCs or HCFCs.