Styrofoam is a "trademarked brand of closed-cell "extruded polystyrene foam (XPS), commonly called "Blue Board" manufactured as foam continuous "building insulation board used in walls, roofs, and foundations as "thermal insulation and water barrier. This material is light blue in color and is owned and manufactured by "The Dow Chemical Company.
In the "United States and "Canada, the colloquial use of the word styrofoam refers to another material that is usually white in color and made of expanded (not extruded) "polystyrene foam "EPS used in "disposable coffee cups, coolers, or "cushioning material in "packaging,  The "term is used generically although it is a different material from the extruded polystyrene used for Styrofoam "insulation.
The Styrofoam brand polystyrene foam, which is used for craft applications, can be identified by its roughness and the "crunch" it makes when cut. Additionally, it is moderately soluble in many organic solvents, "cyanoacrylate, and the propellants and solvents of "spray paint.
In 1947, researchers in Dow's Chemical Physics Lab found a way to make foamed polystyrene. Led by "Ray McIntire, they rediscovered a method first used by "Swedish inventor "Carl Georg Munters. Dow acquired exclusive rights to use Munters' patents and found ways to make large quantities of extruded polystyrene as a closed cell foam that resists moisture.
Styrofoam has a variety of uses. Dow produces Styrofoam building materials, including varieties of "building insulation sheathing and pipe insulation. The claimed "R-value of Styrofoam insulation is five per inch.
Styrofoam is composed of 98% air, making it lightweight and buoyant.
Dow also produces Styrofoam as "structural insulated panels 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.
The EPA and International Agency for Research on Cancer consider styrene a possible human "carcinogen. The American National Bureau of Standards Center for Fire Research found 57 chemical by-products released during the combustion of expanded polystyrene (EPS) foam. On July 1, 2015, "New York City became the largest city in America to attempt to prohibit the sale, possession and distribution of single-use polystyrene foam (the initial decision was overturned on appeal). In San Francisco, supervisors approved the toughest ban on "Styrofoam" (EPS) in the US which went into effect January 1, 2017. The city's Department of the Environment can make exceptions for certain uses like shipping medicines at prescribed temperatures.
In 2015, researchers discovered that "mealworms, the larvae form of the darkling beetle Tenebrio molitor, could digest and subsist healthily on a diet of EPS, commonly referred to as "Styrofoam" colloquially. About 100 mealworms could consume between 34 and 39 milligrams of this white foam in a day. The droppings of mealworm were found to be safe for use as soil for crops. Superworms ("Zophobas morio) are also reported to eat EPS.