関連ワード:  is polystyrene combustible    is styrofoam combustible    is styrofoam combustible japan    is polystyrene flammable    is polystyrene flammable in uk    is extruded polystyrene combustible    is polystyrene non combustible    is expanded polystyrene combustible    is polystyrene insulation combustible    is polystyrene a fire hazard