Frequently Asked Questions

Expanded Polystyrene (EPS) Facts

 What is polystyrene?

We interact and benefit every day from products manufactured from polystyrene plastic, including thermal insulation for construction applications and cushion packaging for industrial and consumer applications.

There are two common types of polystyrene foam: extruded polystyrene (popularly known by its Dow trademark, Styrofoam®) and expanded polystyrene (EPS). The common coffee cup is a perfect example of expanded polystyrene. This is the same material you find when you unpack a new television, stereo, computer, or other delicate consumer product.

Both expanded polystyrene (EPS) and extruded polystyrene are used extensively as thermal insulation in industrial, commercial and residential construction.

What is expanded polystyrene (EPS)?

Expanded Polystyrene (EPS) is a thermoplastic, closed-cell, lightweight, rigid-foam plastic. The low thermal conductivity, high compressive, strength and excellent shock absorption properties of EPS makes it an ideal material for the application demand for which it is used.

Polystyrene foams are produced using blowing agents that form bubbles and expand the foam. In expanded polystyrene, these are usually hydrocarbons such as pentane, which may pose a flammability hazard in manufacturing or storage of newly manufactured material, but have a relatively mild environmental impact.

 What is Extruded Polystyrene (XPS)?

Extruded polystyrene is usually made with hydrofluorocarbons (HFC-134a) which have global warming potentials of approximately 1000–1300 times that of carbon dioxide.

 Does EPS Foam insulation contain chlorofluorocarbons (CFCs) or HCFCs?

No. EPS foam products have never been manufactured with CFCs. The expansion agent for EPS material is pentane which may pose a flammability hazard in manufacturing or storage of newly manufactured material but has a relatively mild environmental impact.

 Are expanded polystyrene (EPS) and extruded polystyrene (XPS) the same?

No. Extruded polystyrene (often in colors such as pink, blue or green) uses a different blowing agent and a different manufacturing process. EPS insulation systems dramatically reduce energy consumption and its resultant pollution.

 Does EPS foam give off toxic emissions when incinerated?

No. EPS foam’s chemical makeup consists of carbon and hydrogen. When completely combusted, it gives off water vapor, carbon dioxide, and trace levels of ash – the same as paper. It also takes a great deal of heat to make EPS foam burn. In normal situations, it simply melts.

 Is EPS considered toxic? Does it contain formaldehyde?

The simple chemical makeup of EPS is carbon, hydrogen, and oxygen – elements found in wood and other organic materials.  EPS foam products do NOT contain formaldehyde.

Both EPS and XPS can be used for insulation and some gas escapes from both types of foam. In EPS foam that gas is air since EPS is made with steam. In XPS that gas is primarily Tetrafluoroethane a dangerous chlorofluorocarbon also used as a refrigerant. (

 Is EPS foam recyclable?

Yes. Many manufacturers recycle their waste beads and reuse all materials or convert it into other products. The EPS Industry Alliance works closely with the plastics industry to develop recycling techniques and technology that are both efficient and economical. The goal of manufacturers is zero EPS in landfills.

Does EPS Biodegrade?

Although EPS foam does not biodegrade, it is benign to the environment and provides a stable fill material similar to earth, rock or concrete. Our goal is to limit waste construction materials which is why the BuildBlock 1-inch repeating interlock pattern is so important. This means that you will never need to cut off more than 1-inch of foam to maintain connections. Most other ICFs use a much larger pattern and have a greater amount of waste.

What are the benefits of EPS thermal insulation?

EPS foam is one of the longest-lasting, cost-effective, and efficient building materials on the market. Recyclable and non-toxic it can keep our homes and businesses energy efficient for centuries.

What about Polyurethane?

Polyurethane is a polymer composed of a chain of organic units joined by carbamate (urethane) links. Polyurethane polymer is a combustible solid and can be ignited if exposed to an open flame. Decomposition from fire can produce mainly carbon monoxide, and trace nitrogen oxides, and hydrogen cyanide.

Where can I find unbiased information?

Information for this document came from several sources. We always recommend that consumers do their own research and decide for themselves.


Sources Consulted: