A composition comprising: (i) expanded or expandable polystyrene beads or particles (ii) an intumescent, and (iii) a fire-resistant binder the weight of (i) being in the range 20-75% by weight based on the total weight of (i), (ii) and (iii) is disclosed. The fire-resistant binder is an inorganic material chosen from the list comprising metal, silicates, metal aluminates, metal amminosilicates and zeolites preferably an aqueous solution of sodium silicate. A method of preparing a fire-retardant polystyrene is also disclosed.