In the United States and Canada, the word Styrofoam refers to expanded (not extruded) polystyrene foam, such as disposable coffee cups, coolers, or cushioning material in packaging, which are typically white and are made of expanded polystyrene beads. This is a different material from the extruded polystyrene used for Styrofoam insulation. The polystyrene foam used for craft applications, which can be identified by its roughness and by the fact that it "crunches" when cut, is moderately soluble in many organic solvents, cyanoacrylate, and the propellants and solvents of spray paint, and is not specifically identified as expanded or extruded. Another trade name for expanded polystyrene is thermacol, originated by BASF.
Styrofoam is composed of ninety-eight percent air, making it light weight and buoyant. Because of its insulating properties and buoyancy, it was adopted in 1942 by the United States Coast Guard for use in a six-person life raft.
In 1971 a Dutch marine salvage company, Smit International, used styrofoam balls to refloat part of a wrecked bulk carrier, the London Valour. Smit succeeded in towing the wreck for about 90 miles (140 kilometers) but it then sank, spilling large amounts of Styrofoam on the surface of the sea.
Styrofoam has since found a variety of uses. Dow produces Styrofoam building materials, including insulated sheathing and pipe insulation. The claimed R-value of Styrofoam insulation is five per inch.
Dow also produces Styrofoam as a structural material for use by florists and in craft products. Dow insulation Styrofoam has a distinctive blue color; Styrofoam for craft applications is available in white and green.
Styrofoam can be used under roads and other structures to prevent soil disturbances due to freezing and thawing.