Why don't we choose Eps to construct buildings? EPS is an ECO friendly substance does not contain CFCs or HCFCs which diminish the ozone layer.Another quality's of EPS are Durable, Moisture Resistance, Thermal insulation, Ridigty of EPS makes it an effective.Due to the Thermal insulation property significant energy saved by heating and cooling buildings and a dramatic reduction in the emission of polluting gases.

I found the pros of eps in the below link can anybody shares its cons.
http://www.nppfdubai.com/en/contents/view/go-green.html

On the negative side, EPS emits toxic smoke and melts into flowing burning goo, when fully engulfed. (Polyisocyanurate & polyurethane foams emit toxic smoke when burning, but char in place rather than spreading as a burning liquid.)

People DO construct buildings using EPS for structural purpose, as insulating filler supporting reinforced concrete monocoques in SCIP designs, or with OSB or metal skinned SIPs.